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Svedung Wettervik T, Engquist H, Howells T, Hånell A, Rostami E, Ronne-Engström E, Lewén A, Enblad P. Higher intracranial pressure variability is associated with lower cerebrovascular resistance in aneurysmal subarachnoid hemorrhage. J Clin Monit Comput 2023; 37:319-326. [PMID: 35842879 PMCID: PMC9852113 DOI: 10.1007/s10877-022-00894-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 07/04/2022] [Indexed: 01/24/2023]
Abstract
Higher intracranial pressure variability (ICPV) has been associated with a more favorable cerebral energy metabolism, lower rate of delayed ischemic neurologic deficits, and more favorable outcome in aneurysmal subarachnoid hemorrhage (aSAH). We have hypothesized that higher ICPV partly reflects more compliant and active cerebral vessels. In this study, the aim was to further test this by investigating if higher ICPV was associated with lower cerebrovascular resistance (CVR) and higher cerebral blood flow (CBF) after aSAH. In this observational study, 147 aSAH patients were included, all of whom had been treated in the Neurointensive Care (NIC) Unit, Uppsala, Sweden, 2012-2020. They were required to have had ICP monitoring and at least one xenon-enhanced computed tomography (Xe-CT) scan to study cortical CBF within the first 2 weeks post-ictus. CVR was defined as the cerebral perfusion pressure in association with the Xe-CT scan divided by the concurrent CBF. ICPV was defined over three intervals: subminute (ICPV-1m), 30-min (ICPV-30m), and 4 h (ICPV-4h). The first 14 days were divided into early (days 1-3) and vasospasm phase (days 4-14). In the vasospasm phase, but not in the early phase, higher ICPV-4h (β = - 0.19, p < 0.05) was independently associated with a lower CVR in a multiple linear regression analysis and with a higher global cortical CBF (r = 0.19, p < 0.05) in a univariate analysis. ICPV-1m and ICPV-30m were not associated with CVR or CBF in any phase. This study corroborates the hypothesis that higher ICPV, at least in the 4-h interval, is favorable and may reflect more compliant and possibly more active cerebral vessels.
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Affiliation(s)
- Teodor Svedung Wettervik
- Section of Neurosurgery, Department of Medical Sciences, Uppsala University, 751 85, Uppsala, Sweden.
| | - Henrik Engquist
- Department of Surgical Sciences/Anesthesia and Intensive Care, Uppsala University, 751 85, Uppsala, Sweden
| | - Timothy Howells
- Section of Neurosurgery, Department of Medical Sciences, Uppsala University, 751 85, Uppsala, Sweden
| | - Anders Hånell
- Section of Neurosurgery, Department of Medical Sciences, Uppsala University, 751 85, Uppsala, Sweden
| | - Elham Rostami
- Section of Neurosurgery, Department of Medical Sciences, Uppsala University, 751 85, Uppsala, Sweden
| | - Elisabeth Ronne-Engström
- Section of Neurosurgery, Department of Medical Sciences, Uppsala University, 751 85, Uppsala, Sweden
| | - Anders Lewén
- Section of Neurosurgery, Department of Medical Sciences, Uppsala University, 751 85, Uppsala, Sweden
| | - Per Enblad
- Section of Neurosurgery, Department of Medical Sciences, Uppsala University, 751 85, Uppsala, Sweden
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Shigefuku R, Takahashi H, Watanabe T, Hattori N, Ikeda H, Matsunaga K, Ehira T, Suzuki T, Matsumoto N, Okuse C, Iwasa M, Nakagawa H, Itoh F, Suzuki M. Effects of endoscopic injection sclerotherapy for esophagogastric varices on portal hemodynamics and liver function. BMC Gastroenterol 2022; 22:350. [PMID: 35864442 PMCID: PMC9306194 DOI: 10.1186/s12876-022-02422-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 07/06/2022] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVES To identify patients suitable for endoscopic injection sclerotherapy (EIS) by evaluating their portal hemodynamics and liver function. METHODS We selected 58 patients with esophagogastric varices (EGV) and liver cirrhosis (LC) related to either hepatitis C virus (C) (n = 19), hepatitis B virus (n = 2), alcohol (AL) (n = 20), C + AL (n = 6), non-alcoholic steatohepatitis (n = 6), others (n = 3), or non-LC (n = 2). All patients underwent EIS. We measured their portal venous tissue blood flow (PVTBF) and hepatic arterial tissue blood flow (HATBF) using xenon computed tomography before and after EIS. We classified them into increased group and decreased group according to the PVTBF to identify the predictors that contribute to PVTBF increase post-EIS. RESULTS Low value of indocyanine green retention at 15 min (ICG-R15), the absence of paraesophageal veins, and low baseline PVTBF/HATBF (P/A) ratio predicted increased PVTBF in the multivariate logistic analysis (odds ratio (OR) 10.46, p = 0.0391; OR 12.45, p = 0.0088; OR 13.57, p = 0.0073). The protein synthetic ability improved 1 year post-EIS in increased group. Cox proportional hazards regression identified alcohol drinking (hazard ratio; 3.67, p = 0.0261) as an independent predictor of EGV recurrence. CONCLUSIONS Patients with low ICG-R15, low P/A ratio, and the absence of paraesophageal veins were probable predictors of PVTBF improvement post-EIS. In addition, the improvement of hepatic hemodynamics likely enhanced liver function following EIS.
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Affiliation(s)
- Ryuta Shigefuku
- Department of Gastroenterology and Hepatology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, 514-8507, Japan. .,Division of Gastroenterology and Hepatology, Department of Internal Medicine, School of Medicine, St. Marianna University, Kawasaki, 216-8511, Japan.
| | - Hideaki Takahashi
- Department of Gastroenterology and Hepatology, Yokohama City Seibu Hospital, St. Marianna University, Yokohama, Japan.,Division of Gastroenterology and Hepatology, Department of Internal Medicine, School of Medicine, St. Marianna University, Kawasaki, 216-8511, Japan
| | - Tsunamasa Watanabe
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, School of Medicine, St. Marianna University, Kawasaki, 216-8511, Japan
| | - Nobuhiro Hattori
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, School of Medicine, St. Marianna University, Kawasaki, 216-8511, Japan
| | - Hiroki Ikeda
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, School of Medicine, St. Marianna University, Kawasaki, 216-8511, Japan
| | - Kotaro Matsunaga
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, School of Medicine, St. Marianna University, Kawasaki, 216-8511, Japan
| | - Takuya Ehira
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, School of Medicine, St. Marianna University, Kawasaki, 216-8511, Japan
| | - Tatsuya Suzuki
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, School of Medicine, St. Marianna University, Kawasaki, 216-8511, Japan
| | - Nobuyuki Matsumoto
- Department of Gastroenterology and Hepatology, Yokohama City Seibu Hospital, St. Marianna University, Yokohama, Japan
| | - Chiaki Okuse
- Division of General Internal Medicine, Department of Internal Medicine, Kawasaki Municipal Tama Hospital, Kawasaki, Japan
| | - Motoh Iwasa
- Department of Gastroenterology and Hepatology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, 514-8507, Japan
| | - Hayato Nakagawa
- Department of Gastroenterology and Hepatology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, 514-8507, Japan
| | - Fumio Itoh
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, School of Medicine, St. Marianna University, Kawasaki, 216-8511, Japan
| | - Michihiro Suzuki
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, School of Medicine, St. Marianna University, Kawasaki, 216-8511, Japan.,Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kawasaki Municipal Tama Hospital, Kawasaki, Japan
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Svedung Wettervik T, Engquist H, Hånell A, Howells T, Rostami E, Ronne-Engström E, Lewén A, Enblad P. Cerebral Blood Flow and Oxygen Delivery in Aneurysmal Subarachnoid Hemorrhage: Relation to Neurointensive Care Targets. Neurocrit Care 2022; 37:281-292. [PMID: 35449343 PMCID: PMC9283361 DOI: 10.1007/s12028-022-01496-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 03/22/2022] [Indexed: 02/04/2023]
Abstract
Background The primary aim was to determine to what extent continuously monitored neurointensive care unit (neuro-ICU) targets predict cerebral blood flow (CBF) and delivery of oxygen (CDO2) after aneurysmal subarachnoid hemorrhage. The secondary aim was to determine whether CBF and CDO2 were associated with clinical outcome. Methods In this observational study, patients with aneurysmal subarachnoid hemorrhage treated at the neuro-ICU in Uppsala, Sweden, from 2012 to 2020 with at least one xenon-enhanced computed tomography (Xe-CT) obtained within the first 14 days post ictus were included. CBF was measured with the Xe-CT and CDO2 was calculated based on CBF and arterial oxygen content. Regional cerebral hypoperfusion was defined as CBF < 20 mL/100 g/min, and poor CDO2 was defined as CDO2 < 3.8 mL O2/100 g/min. Neuro-ICU variables including intracranial pressure (ICP), pressure reactivity index, cerebral perfusion pressure (CPP), optimal CPP, and body temperature were assessed in association with the Xe-CT. The acute phase was divided into early phase (day 1–3) and vasospasm phase (day 4–14). Results Of 148 patients, 27 had underwent a Xe-CT only in the early phase, 74 only in the vasospasm phase, and 47 patients in both phases. The patients exhibited cerebral hypoperfusion and poor CDO2 for medians of 15% and 30%, respectively, of the cortical brain areas in each patient. In multiple regressions, higher body temperature was associated with higher CBF and CDO2 in the early phase. In a similar regression for the vasospasm phase, younger age and longer pulse transit time (lower peripheral resistance) correlated with higher CBF and CDO2, whereas lower hematocrit only correlated with higher CBF but not with CDO2. ICP, CPP, and pressure reactivity index exhibited no independent association with CBF and CDO2. R2 of these regressions were below 0.3. Lower CBF and CDO2 in the early phase correlated with poor outcome, but this only held true for CDO2 in multiple regressions. Conclusions Systemic and cerebral physiological variables exhibited a modest association with CBF and CDO2. Still, cerebral hypoperfusion and low CDO2 were common and low CDO2 was associated with poor outcome. Xe-CT imaging could be useful to help detect secondary brain injury not evident by high ICP and low CPP. Supplementary Information The online version contains supplementary material available at 10.1007/s12028-022-01496-1.
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Affiliation(s)
| | - Henrik Engquist
- Department of Surgical Sciences/Anesthesia and Intensive Care, Uppsala University, Uppsala, Sweden
| | - Anders Hånell
- Section of Neurosurgery, Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Timothy Howells
- Section of Neurosurgery, Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Elham Rostami
- Section of Neurosurgery, Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | | | - Anders Lewén
- Section of Neurosurgery, Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Per Enblad
- Section of Neurosurgery, Department of Neuroscience, Uppsala University, Uppsala, Sweden
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Jang JH, Solarana K, Hammer DX, Fisher JAN. Dissecting the microvascular contributions to diffuse correlation spectroscopy measurements of cerebral hemodynamics using optical coherence tomography angiography. NEUROPHOTONICS 2021; 8:025006. [PMID: 33912621 PMCID: PMC8071783 DOI: 10.1117/1.nph.8.2.025006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
Significance: Diffuse correlation spectroscopy (DCS) is an emerging noninvasive, diffuse optical modality that purportedly enables direct measurements of microvasculature blood flow. Functional optical coherence tomography angiography (OCT-A) can resolve blood flow in vessels as fine as capillaries and thus has the capability to validate key attributes of the DCS signal. Aim: To characterize activity in cortical vasculature within the spatial volume that is probed by DCS and to identify populations of blood vessels that are most representative of the DCS signals. Approach: We performed simultaneous measurements of somatosensory-evoked cerebral blood flow in mice in vivo using both DCS and OCT-A. Results: We resolved sensory-evoked blood flow in the somatosensory cortex with both modalities. Vessels with diameters smaller than 10 μ m featured higher peak flow rates during the initial poststimulus positive increase in flow, whereas larger vessels exhibited considerably larger magnitude of the subsequent undershoot. The simultaneously recorded DCS waveforms correlated most highly with flow in the smallest vessels, yet featured a more prominent undershoot. Conclusions: Our direct, multiscale, multimodal cross-validation measurements of functional blood flow support the assertion that the DCS signal preferentially represents flow in microvasculature. The significantly greater undershoot in DCS, however, suggests a more spatially complex relationship to flow in cortical vasculature during functional activation.
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Affiliation(s)
- James H. Jang
- Center for Devices and Radiological Health, U. S. Food and Drug Administration, Silver Spring, Maryland, United States
| | - Krystyna Solarana
- Center for Devices and Radiological Health, U. S. Food and Drug Administration, Silver Spring, Maryland, United States
| | - Daniel X. Hammer
- Center for Devices and Radiological Health, U. S. Food and Drug Administration, Silver Spring, Maryland, United States
| | - Jonathan A. N. Fisher
- New York Medical College, Department of Physiology, Valhalla, New York, United States
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Mohan R, Liu AY, Brown PD, Mahajan A, Dinh J, Chung C, McAvoy S, McAleer MF, Lin SH, Li J, Ghia AJ, Zhu C, Sulman EP, de Groot JF, Heimberger AB, McGovern SL, Grassberger C, Shih H, Ellsworth S, Grosshans DR. Proton therapy reduces the likelihood of high-grade radiation-induced lymphopenia in glioblastoma patients: phase II randomized study of protons vs photons. Neuro Oncol 2021; 23:284-294. [PMID: 32750703 PMCID: PMC7906048 DOI: 10.1093/neuonc/noaa182] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND We investigated differences in radiation-induced grade 3+ lymphopenia (G3+L), defined as an absolute lymphocyte count (ALC) nadir of <500 cells/µL, after proton therapy (PT) or X-ray (photon) therapy (XRT) for patients with glioblastoma (GBM). METHODS Patients enrolled in a randomized phase II trial received PT (n = 28) or XRT (n = 56) concomitantly with temozolomide. ALC was measured before, weekly during, and within 1 month after radiotherapy. Whole-brain mean dose (WBMD) and brain dose-volume indices were extracted from planned dose distributions. Univariate and multivariate logistic regression analyses were used to identify independent predictive variables. The resulting model was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS Rates of G3+L were lower in men (7/47 [15%]) versus women (19/37 [51%]) (P < 0.001), and for PT (4/28 [14%]) versus XRT (22/56 [39%]) (P = 0.024). G3+L was significantly associated with baseline ALC, WBMD, and brain volumes receiving 5‒40 Gy(relative biological effectiveness [RBE]) or higher (ie, V5 through V40). Stepwise multivariate logistic regression analysis identified being female (odds ratio [OR] 6.2, 95% confidence interval [CI]: 1.95‒22.4, P = 0.003), baseline ALC (OR 0.18, 95% CI: 0.05‒0.51, P = 0.003), and whole-brain V20 (OR 1.07, 95% CI: 1.03‒1.13, P = 0.002) as the strongest predictors. ROC analysis yielded an area under the curve of 0.86 (95% CI: 0.79-0.94) for the final G3+L prediction model. CONCLUSIONS Sex, baseline ALC, and whole-brain V20 were the strongest predictors of G3+L for patients with GBM treated with radiation and temozolomide. PT reduced brain volumes receiving low and intermediate doses and, consequently, reduced G3+L.
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Affiliation(s)
- Radhe Mohan
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Amy Y Liu
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Paul D Brown
- Department of Radiation Oncology, Mayo Clinic Hospital, Rochester, Minnesota
| | - Anita Mahajan
- Department of Radiation Oncology, Mayo Clinic Hospital, Rochester, Minnesota
| | - Jeffrey Dinh
- Millennium Physicians Radiation Oncology, The Woodlands, Texas
| | - Caroline Chung
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Sarah McAvoy
- Department of Radiation Oncology, University of Maryland, Baltimore, Maryland
| | - Mary Frances McAleer
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Steven H Lin
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Jing Li
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Amol J Ghia
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Cong Zhu
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas
- Department of Epidemiology, Human Genetics and Environmental Sciences, School of Public Health, The University of Texas Health Science Center, Houston, Texas
| | - Erik P Sulman
- Department of Radiation Oncology, NYU Grossman School of Medicine, New York, New York
| | - John F de Groot
- Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Amy B Heimberger
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Susan L McGovern
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Clemens Grassberger
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
| | - Helen Shih
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
| | - Susannah Ellsworth
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana
| | - David R Grosshans
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
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Engquist H, Lewén A, Hillered L, Ronne-Engström E, Nilsson P, Enblad P, Rostami E. CBF changes and cerebral energy metabolism during hypervolemia, hemodilution, and hypertension therapy in patients with poor-grade subarachnoid hemorrhage. J Neurosurg 2021; 134:555-564. [PMID: 31923897 DOI: 10.3171/2019.11.jns192759] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 11/05/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Despite the multifactorial pathogenesis of delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH), augmentation of cerebral blood flow (CBF) is still considered essential in the clinical management of DCI. The aim of this prospective observational study was to investigate cerebral metabolic changes in relation to CBF during therapeutic hypervolemia, hemodilution, and hypertension (HHH) therapy in poor-grade SAH patients with DCI. METHODS CBF was assessed by bedside xenon-enhanced CT at days 0-3, 4-7, and 8-12, and the cerebral metabolic state by cerebral microdialysis (CMD), analyzing glucose, lactate, pyruvate, and glutamate hourly. At clinical suspicion of DCI, HHH therapy was instituted for 5 days. CBF measurements and CMD data at baseline and during HHH therapy were required for study inclusion. Non-DCI patients with measurements in corresponding time windows were included as a reference group. RESULTS In DCI patients receiving HHH therapy (n = 12), global cortical CBF increased from 30.4 ml/100 g/min (IQR 25.1-33.8 ml/100 g/min) to 38.4 ml/100 g/min (IQR 34.2-46.1 ml/100 g/min; p = 0.006). The energy metabolic CMD parameters stayed statistically unchanged with a lactate/pyruvate (L/P) ratio of 26.9 (IQR 22.9-48.5) at baseline and 31.6 (IQR 22.4-35.7) during HHH. Categorized by energy metabolic patterns during HHH, no patient had severe ischemia, 8 showed derangement corresponding to mitochondrial dysfunction, and 4 were normal. The reference group of non-DCI patients (n = 11) had higher CBF and lower L/P ratios at baseline with no change over time, and the metabolic pattern was normal in all these patients. CONCLUSIONS Global and regional CBF improved and the cerebral energy metabolic CMD parameters stayed statistically unchanged during HHH therapy in DCI patients. None of the patients developed metabolic signs of severe ischemia, but a disturbed energy metabolic pattern was a common occurrence, possibly explained by mitochondrial dysfunction despite improved microcirculation.
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Affiliation(s)
- Henrik Engquist
- Departments of1Neuroscience/Neurosurgery and
- 2Surgical Sciences/Anesthesia and Intensive Care, Uppsala University, Uppsala, Sweden
| | | | | | | | | | - Per Enblad
- Departments of1Neuroscience/Neurosurgery and
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Temporal Dynamics of Cerebral Blood Flow During the Acute Course of Severe Subarachnoid Hemorrhage Studied by Bedside Xenon-Enhanced CT. Neurocrit Care 2020; 30:280-290. [PMID: 30790226 PMCID: PMC6420446 DOI: 10.1007/s12028-019-00675-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Background Compromised cerebral blood flow (CBF) is a crucial factor in delayed cerebral ischemia after subarachnoid hemorrhage (SAH). Repeated measurement of CBF may improve our understanding of the temporal dynamics following SAH. The aim of this study was to assess CBF at different phases of the acute course in poor-grade SAH patients, hypothesizing more pronounced disturbances at day 4–7, and that the initial level of CBF determines the following course of CBF. Methods Mechanically ventilated SAH patients were scheduled for bedside measurement of regional and global cortical CBF at day 0–3, 4–7, and 8–12, using xenon-enhanced computed tomography in a mobile setup. Patients were dichotomized depending on high or low initial global cortical CBF and cutoff level 30 ml/100 g/min. Results Eighty-one patients were included, and 51 had measurements at day 0–3 and 4–7. In patients with high initial CBF, the level was unchanged at day 4–7; 37.7 (IQR 32.6–46.7) ml/100 g/min versus 36.8 (IQR 29.5–44.8). The low-CBF group showed a slight increase from 23.6 (IQR 21.0–28.1) ml/100 g/min to 28.4 (IQR 22.7–38.3) (P = 0.025), still markedly lower than the high-CBF group (P = 0.016). In the low-CBF group, CBF increased in patients who received hypertension, hypervolemia, and hemodilution (HHH therapy) but remained low in standard treated patients. For the subset of 27 patients examined also at day 8–12, the differences depending on initial CBF level were no longer statistically significant. Among patients with still low CBF at day 4–7, the proportion who had poor short-term outcome was 55% compared to 35% (n.s.) for patients with high CBF. Conclusions CBF studied in poor-grade SAH patients at large did not show any statistically significant changes over time. Stratifying patients by high or low initial CBF and whether HHH therapy was given revealed an association between low initial CBF and persistent low CBF at day 4–7. These findings may be of clinical relevance in managing SAH patients with low early CBF.
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Effect of HHH-Therapy on Regional CBF after Severe Subarachnoid Hemorrhage Studied by Bedside Xenon-Enhanced CT. Neurocrit Care 2019; 28:143-151. [PMID: 28983856 PMCID: PMC5948237 DOI: 10.1007/s12028-017-0439-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Background Management of delayed cerebral ischemia (DCI) following subarachnoid hemorrhage (SAH) is difficult and still carries controversies. In this study, the effect of therapeutic hypervolemia, hemodilution, and hypertension (HHH-therapy) on cerebral blood flow (CBF) was assessed by xenon-enhanced computerized tomography (XeCT) hypothesizing an increase in CBF in poorly perfused regions. Methods Bedside XeCT measurements of regional CBF in mechanically ventilated SAH patients were routinely scheduled for day 0–3, 4–7, and 8–12. At clinical suspicion of DCI, patients received 5-day HHH-therapy. For inclusion, XeCT was required at 0–48 h before start of HHH (baseline) and during therapy. Data from corresponding time-windows were also collected for non-DCI patients. Results Twenty patients who later developed DCI were included, and twenty-eight patients without DCI were identified for comparison. During HHH, there was a slight nonsignificant increase in systolic blood pressure (SBP) and a significant reduction in hematocrit. Median global cortical CBF for the DCI group increased from 29.5 (IQR 24.6–33.9) to 38.4 (IQR 27.0–41.2) ml/100 g/min (P = 0.001). There was a concomitant increase in regional CBF of the worst vascular territories, and the proportion of area with blood flow below 20 ml/100 g/min was significantly reduced. Non-DCI patients showed higher CBF at baseline, and no significant change over time. Conclusions HHH-therapy appeared to increase global and regional CBF in DCI patients. The increase in SBP was small, while the decrease in hematocrit was more pronounced, which may suggest that intravascular volume status and rheological effects are of importance. XeCT may be potentially helpful in managing poor-grade SAH patients.
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He L, Baker WB, Milej D, Kavuri VC, Mesquita RC, Busch DR, Abramson K, Jiang JY, Diop M, St. Lawrence K, Amendolia O, Quattrone F, Balu R, Kofke WA, Yodh AG. Noninvasive continuous optical monitoring of absolute cerebral blood flow in critically ill adults. NEUROPHOTONICS 2018; 5:045006. [PMID: 30480039 PMCID: PMC6251207 DOI: 10.1117/1.nph.5.4.045006] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 10/29/2018] [Indexed: 05/18/2023]
Abstract
We investigate a scheme for noninvasive continuous monitoring of absolute cerebral blood flow (CBF) in adult human patients based on a combination of time-resolved dynamic contrast-enhanced near-infrared spectroscopy (DCE-NIRS) and diffuse correlation spectroscopy (DCS) with semi-infinite head model of photon propogation. Continuous CBF is obtained via calibration of the DCS blood flow index (BFI) with absolute CBF obtained by intermittent intravenous injections of the optical contrast agent indocyanine green. A calibration coefficient ( γ ) for the CBF is thus determined, permitting conversion of DCS BFI to absolute blood flow units at all other times. A study of patients with acute brain injury ( N = 7 ) is carried out to ascertain the stability of γ . The patient-averaged DCS calibration coefficient across multiple monitoring days and multiple patients was determined, and good agreement between the two calibration coefficients measured at different times during single monitoring days was found. The patient-averaged calibration coefficient of 1.24 × 10 9 ( mL / 100 g / min ) / ( cm 2 / s ) was applied to previously measured DCS BFI from similar brain-injured patients; in this case, absolute CBF was underestimated compared with XeCT, an effect we show is primarily due to use of semi-infinite homogeneous models of the head.
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Affiliation(s)
- Lian He
- University of Pennsylvania, Department of Physics and Astronomy, Philadelphia, Pennsylvania, United States
- Address all correspondence to: Lian He, E-mail:
| | - Wesley B. Baker
- University of Pennsylvania, Department of Physics and Astronomy, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, Department of Anesthesiology and Critical Care, Perelman School of Medicine, Philadelphia, Pennsylvania, United States
| | - Daniel Milej
- Western University, Department of Medical Biophysics, London, Ontario, Canada
- Lawson Health Research Institute, Imaging Division, London, Ontario, Canada
| | - Venkaiah C. Kavuri
- University of Pennsylvania, Department of Physics and Astronomy, Philadelphia, Pennsylvania, United States
| | | | - David R. Busch
- University of Texas Southwestern, Department of Neurology and Neurotherapeutics, Dallas, Texas, United States
- University of Texas Southwestern, Department of Anesthesiology and Pain Management, Dallas, Texas, United States
| | - Kenneth Abramson
- University of Pennsylvania, Department of Physics and Astronomy, Philadelphia, Pennsylvania, United States
| | - Jane Y. Jiang
- University of Pennsylvania, Department of Physics and Astronomy, Philadelphia, Pennsylvania, United States
| | - Mamadou Diop
- Western University, Department of Medical Biophysics, London, Ontario, Canada
- Lawson Health Research Institute, Imaging Division, London, Ontario, Canada
| | - Keith St. Lawrence
- Western University, Department of Medical Biophysics, London, Ontario, Canada
- Lawson Health Research Institute, Imaging Division, London, Ontario, Canada
| | - Olivia Amendolia
- University of Pennsylvania, Department of Neurosurgery, Perelman School of Medicine, Philadelphia, Pennsylvania, United States
| | - Francis Quattrone
- University of Pennsylvania, Department of Neurosurgery, Perelman School of Medicine, Philadelphia, Pennsylvania, United States
| | - Ramani Balu
- University of Pennsylvania, Department of Neurosurgery, Perelman School of Medicine, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, Department of Neurology, Perelman School of Medicine, Philadelphia, Pennsylvania, United States
| | - W. Andrew Kofke
- University of Pennsylvania, Department of Anesthesiology and Critical Care, Perelman School of Medicine, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, Department of Neurosurgery, Perelman School of Medicine, Philadelphia, Pennsylvania, United States
| | - Arjun G. Yodh
- University of Pennsylvania, Department of Physics and Astronomy, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, Department of Anesthesiology and Critical Care, Perelman School of Medicine, Philadelphia, Pennsylvania, United States
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10
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Hemodynamic Disturbances in the Early Phase After Subarachnoid Hemorrhage: Regional Cerebral Blood Flow Studied by Bedside Xenon-enhanced CT. J Neurosurg Anesthesiol 2018; 30:49-58. [PMID: 27906765 DOI: 10.1097/ana.0000000000000395] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The mechanisms leading to neurological deterioration and the devastating course of delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) are still not well understood. Bedside xenon-enhanced computerized tomography (XeCT) enables measurements of regional cerebral blood flow (rCBF) during neurosurgical intensive care. In the present study, CBF characteristics in the early phase after severe SAH were explored and related to clinical characteristics and early clinical course outcome. MATERIALS AND METHODS Patients diagnosed with SAH and requiring mechanical ventilation were prospectively enrolled in the study. Bedside XeCT was performed within day 0 to 3. RESULTS Data from 64 patients were obtained. Median global CBF was 34.9 mL/100 g/min (interquartile range [IQR], 26.7 to 41.6). There was a difference in CBF related to age with higher global CBF in the younger patients (30 to 49 y). CBF was also related to the severity of SAH with lower CBF in Fisher grade 4 compared with grade 3. rCBF disturbances and hypoperfusion were common; in 43 of the 64 patients rCBF<20 mL/100 g/min was detected in more than 10% of the region-of-interest (ROI) area and in 17 patients such low-flow area exceeded 30%. rCBF was not related to the localization of the aneurysm; there was no difference in rCBF of ipsilateral compared with contralateral vascular territories. In patients who initially were in Hunt & Hess grade I to III, median global CBF day 0 to 3 was significantly lower for patients who were in poor neurological state at discharge compared with patients in good neurological state, 25.5 mL/100 g/min (IQR, 21.3 to 28.3) versus 37.8 mL/100 g/min (IQR, 30.5 to 47.6). CONCLUSIONS CBF disturbances are common in the early phase after SAH. In many patients, CBF was heterogenic and substantial areas with low rCBF were detected. Age and CT Fisher grade were factors influencing global cortical CBF. Bedside XeCT may be a tool to identify patients at risk of deteriorating so they can receive intensified management, but this needs further exploration.
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11
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Amen DG, Trujillo M, Keator D, Taylor DV, Willeumier K, Meysami S, Raji CA. Gender-Based Cerebral Perfusion Differences in 46,034 Functional Neuroimaging Scans. J Alzheimers Dis 2018; 60:605-614. [PMID: 28777753 DOI: 10.3233/jad-170432] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Studies have reported that females have widespread increases in regional cerebral blood flow, but the studies were relatively small and inconsistent. OBJECTIVE Here we analyzed a healthy and a very large clinical psychiatric population to determine the effect of gender, using single photon emission computed tomography (SPECT). METHODS Whole brain and region of interest (ROI) gender differences were analyzed in a total of 46,034 SPECT scans at baseline and concentration. The sample included 119 healthy subjects and 26,683 patients (60.4% male, 39.6% female); a subset of 11,587 patients had complete diagnostic information. A total of 128 regions were analyzed according to the AAL Atlas, using ROI Extract and SPSS statistical software programs, controlling for age, diagnoses, and correcting for multiple comparisons. RESULTS Compared to males, healthy females showed significant whole brain (p < 0.01) and ROI increases in 65 baseline and 48 concentration regions (p < 0.01 corrected). Healthy males showed non-significant increases in 9 and 22 regions, respectively. In the clinical group, there were widespread significant increases in females, especially in the prefrontal and limbic regions, and specific increases in males in the inferior occipital lobes, inferior temporal lobes, and lobule 7 and Crus 2 of the cerebellum. These findings were replicated in the subset of 11,587 patients with the effect of diagnoses removed. CONCLUSIONS Our results demonstrated significant gender differences in a healthy and clinical population. Understanding these differences is crucial in evaluating functional neuroimaging and may be useful in understanding the epidemiological gender differences among psychiatric disorders.
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Affiliation(s)
| | - Manuel Trujillo
- Department of Psychiatry, NYU Langone Medical Center, New York, NY, USA
| | - David Keator
- Department of Psychiatry, University of California, Irvine School of Medicine, Brain Imaging Center, Irvine, CA, USA
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12
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Jezzard P, Chappell MA, Okell TW. Arterial spin labeling for the measurement of cerebral perfusion and angiography. J Cereb Blood Flow Metab 2018; 38:603-626. [PMID: 29168667 PMCID: PMC5888859 DOI: 10.1177/0271678x17743240] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Arterial spin labeling (ASL) is an MRI technique that was first proposed a quarter of a century ago. It offers the prospect of non-invasive quantitative measurement of cerebral perfusion, making it potentially very useful for research and clinical studies, particularly where multiple longitudinal measurements are required. However, it has suffered from a number of challenges, including a relatively low signal-to-noise ratio, and a confusing number of sequence variants, thus hindering its clinical uptake. Recently, however, there has been a consensus adoption of an accepted acquisition and analysis framework for ASL, and thus a better penetration onto clinical MRI scanners. Here, we review the basic concepts in ASL and describe the current state-of-the-art acquisition and analysis approaches, and the versatility of the method to perform both quantitative cerebral perfusion measurement, along with quantitative cerebral angiographic measurement.
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Affiliation(s)
- Peter Jezzard
- 1 Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - Thomas W Okell
- 1 Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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13
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Sase S, Yamamoto H, Kawashima E, Tan X, Sawa Y. Discrimination between patients with mild Alzheimer's disease and healthy subjects based on cerebral blood flow images of the lateral views in xenon-enhanced computed tomography. Psychogeriatrics 2018; 18:3-12. [PMID: 28745443 DOI: 10.1111/psyg.12281] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 04/12/2017] [Accepted: 04/27/2017] [Indexed: 11/28/2022]
Abstract
BACKGROUND Quantitative cerebral blood flow (CBF) measurement is expected to help early detection of functional abnormalities caused by Alzheimer's disease (AD) and enable AD treatment to begin in its early stages. Recently, a technique of layer analysis was reported that allowed CBF to be analyzed from the outer to inner layers of the brain. The aim of this work was to develop methods for discriminating between patients with mild AD and healthy subjects based on CBF images of the lateral views created with the layer analysis technique in xenon-enhanced computed tomography. METHODS Xenon-enhanced computed tomography using a wide-volume CT was performed on 17 patients with mild AD aged 75 or older and on 15 healthy age-matched volunteers. For each subject, we created CBF images of the right and left lateral views with a depth of 10-15 mm from the surface of the brain. Ten circular regions of interest (ROI) were placed on each image, and CBF was calculated for each ROI. We determined discriminant ROI that had CBF that could be used to differentiate between the AD and volunteer groups. AD patients' CBF range (mean - SD to mean + SD) and healthy volunteers' CBF range (mean - SD to mean + SD) were obtained for each ROI. Receiver-operator curves were created to identify patients with AD for each of the discriminant ROI and for the AD patients' and healthy volunteers' CBF ranges. RESULTS We selected an ROI on both the right and left temporal lobes as the discriminant ROI. Areas under the receiver-operator curve were 93.3% using the ROI on the right temporal lobe, 95.3% using the ROI on the left temporal lobe, and 92.4% using the AD patients' and healthy volunteers' CBF ranges. CONCLUSIONS We could effectively discriminate between patients with mild AD and healthy subjects using ROI placed on CBF images of the lateral views in xenon-enhanced computed tomography.
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Affiliation(s)
| | | | - Ena Kawashima
- Department of Neuropsychiatry, Sawa Hospital, Osaka, Japan
| | - Xin Tan
- Department of Neuropsychiatry, Sawa Hospital, Osaka, Japan
| | - Yutaka Sawa
- Department of Neuropsychiatry, Sawa Hospital, Osaka, Japan
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14
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Barskiy DA, Coffey AM, Nikolaou P, Mikhaylov DM, Goodson BM, Branca RT, Lu GJ, Shapiro MG, Telkki VV, Zhivonitko VV, Koptyug IV, Salnikov OG, Kovtunov KV, Bukhtiyarov VI, Rosen MS, Barlow MJ, Safavi S, Hall IP, Schröder L, Chekmenev EY. NMR Hyperpolarization Techniques of Gases. Chemistry 2017; 23:725-751. [PMID: 27711999 PMCID: PMC5462469 DOI: 10.1002/chem.201603884] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Indexed: 01/09/2023]
Abstract
Nuclear spin polarization can be significantly increased through the process of hyperpolarization, leading to an increase in the sensitivity of nuclear magnetic resonance (NMR) experiments by 4-8 orders of magnitude. Hyperpolarized gases, unlike liquids and solids, can often be readily separated and purified from the compounds used to mediate the hyperpolarization processes. These pure hyperpolarized gases enabled many novel MRI applications including the visualization of void spaces, imaging of lung function, and remote detection. Additionally, hyperpolarized gases can be dissolved in liquids and can be used as sensitive molecular probes and reporters. This Minireview covers the fundamentals of the preparation of hyperpolarized gases and focuses on selected applications of interest to biomedicine and materials science.
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Affiliation(s)
- Danila A Barskiy
- Department of Radiology, Department of Biomedical Engineering, Department of Physics, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, TN, 37232, USA
| | - Aaron M Coffey
- Department of Radiology, Department of Biomedical Engineering, Department of Physics, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, TN, 37232, USA
| | - Panayiotis Nikolaou
- Department of Radiology, Department of Biomedical Engineering, Department of Physics, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, TN, 37232, USA
| | | | - Boyd M Goodson
- Southern Illinois University, Department of Chemistry and Biochemistry, Materials Technology Center, Carbondale, IL, 62901, USA
| | - Rosa T Branca
- Department of Physics and Astronomy, Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - George J Lu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Mikhail G Shapiro
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | | | - Vladimir V Zhivonitko
- International Tomography Center SB RAS, 630090, Novosibirsk, Russia
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia
| | - Igor V Koptyug
- International Tomography Center SB RAS, 630090, Novosibirsk, Russia
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia
| | - Oleg G Salnikov
- International Tomography Center SB RAS, 630090, Novosibirsk, Russia
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia
| | - Kirill V Kovtunov
- International Tomography Center SB RAS, 630090, Novosibirsk, Russia
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia
| | - Valerii I Bukhtiyarov
- Boreskov Institute of Catalysis SB RAS, 5 Acad. Lavrentiev Pr., 630090, Novosibirsk, Russia
| | - Matthew S Rosen
- MGH/A.A. Martinos Center for Biomedical Imaging, Boston, MA, 02129, USA
| | - Michael J Barlow
- Respiratory Medicine Department, Queen's Medical Centre, University of Nottingham Medical School, Nottingham, NG7 2UH, UK
| | - Shahideh Safavi
- Respiratory Medicine Department, Queen's Medical Centre, University of Nottingham Medical School, Nottingham, NG7 2UH, UK
| | - Ian P Hall
- Respiratory Medicine Department, Queen's Medical Centre, University of Nottingham Medical School, Nottingham, NG7 2UH, UK
| | - Leif Schröder
- Molecular Imaging, Department of Structural Biology, Leibniz-Institut für Molekulare Pharmakologie (FMP), 13125, Berlin, Germany
| | - Eduard Y Chekmenev
- Department of Radiology, Department of Biomedical Engineering, Department of Physics, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, TN, 37232, USA
- Russian Academy of Sciences, 119991, Moscow, Russia
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15
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Discrimination Between Patients With Alzheimer Disease and Healthy Subjects Using Layer Analysis of Cerebral Blood Flow and Xenon Solubility Coefficient in Xenon-Enhanced Computed Tomography. J Comput Assist Tomogr 2017; 41:477-483. [DOI: 10.1097/rct.0000000000000525] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Shigefuku R, Takahashi H, Nakano H, Watanabe T, Matsunaga K, Matsumoto N, Kato M, Morita R, Michikawa Y, Tamura T, Hiraishi T, Hattori N, Noguchi Y, Nakahara K, Ikeda H, Ishii T, Okuse C, Sase S, Itoh F, Suzuki M. Correlations of Hepatic Hemodynamics, Liver Function, and Fibrosis Markers in Nonalcoholic Fatty Liver Disease: Comparison with Chronic Hepatitis Related to Hepatitis C Virus. Int J Mol Sci 2016; 17:E1545. [PMID: 27649152 PMCID: PMC5037819 DOI: 10.3390/ijms17091545] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 09/01/2016] [Accepted: 09/08/2016] [Indexed: 02/07/2023] Open
Abstract
The progression of chronic liver disease differs by etiology. The aim of this study was to elucidate the difference in disease progression between chronic hepatitis C (CHC) and nonalcoholic fatty liver disease (NAFLD) by means of fibrosis markers, liver function, and hepatic tissue blood flow (TBF). Xenon computed tomography (Xe-CT) was performed in 139 patients with NAFLD and 152 patients with CHC (including liver cirrhosis (LC)). The cutoff values for fibrosis markers were compared between NAFLD and CHC, and correlations between hepatic TBF and liver function tests were examined at each fibrosis stage. The cutoff values for detection of the advanced fibrosis stage were lower in NAFLD than in CHC. Although portal venous TBF (PVTBF) correlated with liver function tests, PVTBF in initial LC caused by nonalcoholic steatohepatitis (NASH-LC) was significantly lower than that in hepatitis C virus (C-LC) (p = 0.014). Conversely, the liver function tests in NASH-LC were higher than those in C-LC (p < 0.05). It is important to recognize the difference between NAFLD and CHC. We concluded that changes in hepatic blood flow occurred during the earliest stage of hepatic fibrosis in patients with NAFLD; therefore, patients with NAFLD need to be followed carefully.
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Affiliation(s)
- Ryuta Shigefuku
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
| | - Hideaki Takahashi
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
- Division of Gastroenterology, St. Marianna University School of Medicine, Yokohama City Seibu Hospital, Kanagawa, Yokohama 241-0811, Japan.
| | - Hiroyasu Nakano
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
| | - Tsunamasa Watanabe
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
| | - Kotaro Matsunaga
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
| | - Nobuyuki Matsumoto
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
| | - Masaki Kato
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
| | - Ryo Morita
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
| | - Yousuke Michikawa
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
| | - Tomohiro Tamura
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
- Division of Gastroenterology, St. Marianna University School of Medicine, Yokohama City Seibu Hospital, Kanagawa, Yokohama 241-0811, Japan.
| | - Tetsuya Hiraishi
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kawasaki Municipal Tama Hospital, Kanagawa, Kawasaki 214-8525, Japan.
| | - Nobuhiro Hattori
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
| | - Yohei Noguchi
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
- Division of Gastroenterology, St. Marianna University School of Medicine, Yokohama City Seibu Hospital, Kanagawa, Yokohama 241-0811, Japan.
| | - Kazunari Nakahara
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
| | - Hiroki Ikeda
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
| | - Toshiya Ishii
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kawasaki Municipal Tama Hospital, Kanagawa, Kawasaki 214-8525, Japan.
| | - Chiaki Okuse
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kawasaki Municipal Tama Hospital, Kanagawa, Kawasaki 214-8525, Japan.
| | - Shigeru Sase
- Anzai Medical Company, Ltd., Tokyo 141-0033, Japan.
| | - Fumio Itoh
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
| | - Michihiro Suzuki
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kanagawa, Kawasaki 216-8511, Japan.
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kawasaki Municipal Tama Hospital, Kanagawa, Kawasaki 214-8525, Japan.
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17
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Low SW, Teo K, Lwin S, Yeo LLL, Paliwal PR, Ahmad A, Sinha AK, Teoh HL, Wong LYH, Chong VF, Seet RCS, Chan BPL, Yeo TT, Chou N, Sharma VK. Improvement in cerebral hemodynamic parameters and outcomes after superficial temporal artery-middle cerebral artery bypass in patients with severe stenoocclusive disease of the intracranial internal carotid or middle cerebral arteries. J Neurosurg 2015; 123:662-9. [PMID: 26023999 DOI: 10.3171/2014.11.jns141553] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Both the older and the recent extracranial-intracranial (EC-IC) bypass trials for symptomatic carotid occlusion failed to demonstrate a reduction in stroke recurrence. However, the role of superficial temporal artery (STA)-middle cerebral artery (MCA) bypass in patients with symptomatic intracranial stenoocclusive disease has been rarely evaluated. The authors evaluated serial changes in various cerebral hemodynamic parameters in patients with severe stenoocclusive disease of the intracranial internal carotid artery (ICA) or middle cerebral artery (MCA) and impaired cerebral vasodilatory reserve (CVR), treated by STA-MCA bypass surgery or medical treatment. METHODS Patients with severe stenoocclusive disease of the intracranial ICA or MCA underwent transcranial Doppler (TCD) ultrasonography and CVR assessment using the breath-holding index (BHI). Patients with impaired BHI (< 0.69) were further evaluated with acetazolamide-challenge technitium-99m hexamethylpropyleneamine oxime ((99m)Tc HMPAO) SPECT. STA-MCA bypass surgery was offered to patients with impaired CVR on SPECT. All patients underwent TCD and SPECT at 4 ± 1 months and were followed up for cerebral ischemic events. RESULTS A total of 112 patients were included. This total included 73 men, and the mean age of the entire study population was 56 years (range 23-78 years). (99m)Tc HMPAO SPECT demonstrated impaired CVR in 77 patients (69%). Of these 77 patients, 46 underwent STA-MCA bypass while 31 received best medical treatment. TCD and acetazolamide-challenge (99m)Tc HMPAO SPECT repeated at 4 ± 1 months showed significant improvement in the STA-MCA bypass group. During a mean follow-up of 34 months (range 18-39 months), only 6 (13%) of 46 patients in the bypass group developed cerebral ischemic events, as compared with 14 (45%) of 31 patients receiving medical therapy (absolute risk reduction 32%, p = 0.008). CONCLUSIONS STA-MCA bypass surgery in carefully selected patients with symptomatic severe intracranial stenoocclusive disease of the intracranial ICA or MCA results in significant improvement in hemodynamic parameters and reduction in stroke recurrence.
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Affiliation(s)
| | | | | | | | | | | | - Arvind K Sinha
- Department of Diagnostic Imaging, National University Hospital System, Singapore; and
| | | | | | - Vincent F Chong
- Department of Diagnostic Imaging, National University Hospital System, Singapore; and
| | | | | | | | | | - Vijay K Sharma
- Division of Neurology, and.,YLL School of Medicine, National University of Singapore, Singapore
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18
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Takahashi H, Shigefuku R, Yoshida Y, Ikeda H, Matsunaga K, Matsumoto N, Okuse C, Sase S, Itoh F, Suzuki M. Correlation between hepatic blood flow and liver function in alcoholic liver cirrhosis. World J Gastroenterol 2014; 20:17065-17074. [PMID: 25493018 PMCID: PMC4258574 DOI: 10.3748/wjg.v20.i45.17065] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 04/29/2014] [Indexed: 02/06/2023] Open
Abstract
AIM: To elucidate the correlation between hepatic blood flow and liver function in alcoholic liver cirrhosis (AL-LC).
METHODS: The subjects included 35 patients with AL-LC (34 men, 1 woman; mean age, 58.9 ± 10.7 years; median age, 61 years; range: 37-76 years). All patients were enrolled in this study after obtaining written informed consent. Liver function was measured with tests measuring albumin (Alb), prothrombin time (PT), brain natriuretic peptide (BNP), branched amino acid and tyrosine ratio (BTR), branched chain amino acid (BCAA), tyrosine, ammonia (NH3), cholinesterase (ChE), immunoreactive insulin (IRI), total bile acid (TBA), and the retention rate of indocyanine green 15 min after administration (ICG R15). Hepatic blood flow, hepatic arterial tissue blood flow (HATBF), portal venous tissue blood flow (PVTBF), and total hepatic tissue blood flow (THTBF) were simultaneously calculated using xenon computed tomography.
RESULTS: PVTBF, HATBF and THTBF were 30.2 ± 10.4, 20.0 ± 10.7, and 50.3 ± 14.9 mL/100 mL/min, respectively. Alb, PT, BNP, BTR, BCAA, tyrosine, NH3, ChE, IRI, TBA, and ICG R15 were 3.50 ± 0.50 g/dL, 72.0% ± 11.5%, 63.2 ± 56.7 pg/mL, 4.06 ± 1.24, 437.5 ± 89.4 μmol/L, 117.7 ± 32.8 μmol/L, 59.4 ± 22.7 μg/dL, 161.0 ± 70.8 IU/L, 12.8 ± 5.0 μg/dL, 68.0 ± 51.8 μmol/L, and 28.6% ± 13.5%, respectively. PVTBF showed a significant negative correlation with ICG R15 (r = -0.468, P <0.01). No significant correlation was seen between ICG 15R, HATBF and THTBF. There was a significant correlation between PVTBF and Alb (r = 0.2499, P < 0.05), and NH3 tended to have an inverse correlation with PVTBF (r = -0.2428, P = 0.0894). There were also many significant correlations between ICG R15 and liver function parameters, including Alb, NH3, PT, BNP, TBA, BCAA, and tyrosine (r = -0.2156, P < 0.05; r = 0.4318, P < 0.01; r = 0.4140, P < 0.01; r = 0.3610, P < 0.05; r = 0.5085, P < 0.001; r = 0.4496, P < 0.01; and r = 0.4740, P < 0.05, respectively).
CONCLUSION: Our investigation showed that there is a close correlation between liver function and hepatic blood flow.
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Shigefuku R, Takahashi H, Kato M, Yoshida Y, Suetani K, Noguchi Y, Hatsugai M, Nakahara K, Ikeda H, Kobayashi M, Matsunaga K, Matsumoto N, Okuse C, Itoh F, Maeyama S, Sase S, Suzuki M. Evaluation of hepatic tissue blood flow using xenon computed tomography with fibrosis progression in nonalcoholic fatty liver disease: comparison with chronic hepatitis C. Int J Mol Sci 2014; 15:1026-39. [PMID: 24424317 PMCID: PMC3907854 DOI: 10.3390/ijms15011026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/24/2013] [Accepted: 12/27/2013] [Indexed: 12/27/2022] Open
Abstract
AIMS The present study evaluated the utility of xenon computed tomography (Xe-CT) as a noninvasive diagnostic procedure for the measurement of hepatic tissue blood flow (TBF) in patients with nonalcoholic fatty liver disease (NAFLD) or chronic hepatitis C (CH-C). METHODS Xe-CT was performed in 93 patients with NAFLD and in 109 patients with CH-C. Subjects were classified into one of three groups, based on fibrosis stage: group 1, no bridging fibrosis; group 2, bridging fibrosis; and group 3, liver cirrhosis. Correlations between hepatic TBFs in each fibrosis stage were examined. RESULTS In group 1, portal venous TBF (PVTBF), hepatic arterial (HATBF), and total hepatic TBF (THTBF) were significantly lower in patients with in nonalcoholic steatohepatitis (NASH) than in those with CH-C (p < 0.001, p < 0.05, p < 0.001, respectively). In group 2, PVTBF and THTBF were significantly lower in patients with in NASH than in those with CH-C (p < 0.001, p < 0.05, respectively). In group 3, hepatic TBFs were not significantly different when comparing patients with NASH and those with CH-C. CONCLUSIONS PVTBF decreased due to fat infiltration. Therefore, hemodynamic changes occur relatively earlier in NAFLD than in CH-C. Patients with NASH should be monitored carefully for portal hypertensive complications in the early fibrosis stage.
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Affiliation(s)
- Ryuta Shigefuku
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Hideaki Takahashi
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Masaki Kato
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Yoshihito Yoshida
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Keigo Suetani
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Yohei Noguchi
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Moriaki Hatsugai
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Kazunari Nakahara
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Hiroki Ikeda
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Minoru Kobayashi
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Kotaro Matsunaga
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Nobuyuki Matsumoto
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Chiaki Okuse
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Fumio Itoh
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Shiro Maeyama
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Shigeru Sase
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
| | - Michihiro Suzuki
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Kanagawa, Japan.
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Takahashi H, Suzuki M, Shigefuku R, Okano M, Hiraishi T, Takagi R, Noguchi Y, Hattori N, Hatsugai M, Nakahara K, Okamoto M, Kobayashi M, Ikeda H, Fukuda Y, Nagase Y, Ishii T, Matsunaga K, Matsumoto N, Okuse C, Sase S, Itoh F. Xenon computed tomography can evaluate the improvement of hepatic hemodynamics before and after endoscopic injection sclerotherapy. J Gastroenterol 2013; 48:1353-61. [PMID: 23397117 DOI: 10.1007/s00535-013-0756-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 01/15/2013] [Indexed: 02/10/2023]
Abstract
BACKGROUND Xenon computed tomography (Xe-CT) provides quantitative information on tissue blood flow (TBF). In the present study, Xe-CT was performed in patients with esophagogastric varices (EGV) before and after endoscopic injection sclerotherapy (EIS) to evaluate hepatic blood flow (HBF), hepatic arterial TBF (HATBF) and portal venous TBF (PVTBF). METHODS Subjects comprised of 88 patients with EGV (49 men, 39 women, average age 65.8 ± 11.5 years, median age 68 years, 30-86 years) and liver cirrhosis related to either hepatitis C virus (C) (n = 33), hepatitis B virus (B) (n = 3), alcohol (AL) (n = 22), AL + C (n = 7), AL + B (n = 1), B + C + AL (n = 1), nonalcoholic steatohepatitis (NASH) (n = 4), autoimmune hepatitis (AIH) (n = 5), primary biliary cirrhosis (PBC) (n = 2), or cryptogenic (n = 10) were enrolled. All patients, who were enrolled in this study, were performed EIS for prophylaxis. Xe-CT and measurement of the retention rate of indocyanine green 15 min after administration (ICG R15) were performed before and after EIS. Total hepatic TBF (THTBF) and PVTBF/HATBF ratio (P/A) were also calculated. RESULTS PVTBF, HATBF, THTBF, P/A and ICG R15 before EIS were 28.3 ± 8.91, 22.5 ± 14.4 and 50.8 ± 17.6 ml/100 ml/min, 1.62 ± 0.71 and 28.8 ± 12.7 %, respectively and those after EIS were 31.9 ± 10.0, 19.3 ± 11.6, and 51.2 ± 17.0 ml/100 ml/min, 1.92 ± 0.84 and 23.6 ± 11.3 %, respectively. PVTBF and P/A after EIS were significantly higher than those before EIS (p = 0.00444, p = 0.0179, respectively), and HATBF and ICG R15 after EIS were significantly lower than those before EIS (p = 0.00129, p < 0.001, respectively). CONCLUSIONS Xenon computed tomography showed that PVTBF increased after EIS for EGV and HATBF decreased in response to an increase in PVTBF.
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Affiliation(s)
- Hideaki Takahashi
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine, 2-16-1 Sugao Miyamae-ku, Kawasaki, Kanagawa, 216-8511, Japan,
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Cao W, Cheng X, Li H, Wang L, Zhang X, Dong Q. Evaluation of cerebrovascular reserve using xenon-enhanced CT scanning in patients with symptomatic middle cerebral artery stenosis. J Clin Neurosci 2013; 21:293-7. [PMID: 24238634 DOI: 10.1016/j.jocn.2013.04.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 04/18/2013] [Accepted: 04/19/2013] [Indexed: 11/25/2022]
Abstract
Cerebrovascular reserve (CVR) is an important prognostic factor in patients with major cerebral arterial steno-occlusive disease. However, few studies have examined CVR in symptomatic intracranial stenosis without ipsilateral extracranial internal carotid artery stenosis. This study sought to evaluate CVR in patients with symptomatic middle cerebral artery (MCA) stenosis using xenon-enhanced computed tomography (Xe/CT) with acetazolamide (ACZ) challenge. Twelve patients with symptomatic MCA stenosis were recruited. All patients were examined by Xe/CT to quantitatively measure resting cerebral blood flow (CBF) and received ACZ challenge to evaluate CVR. For resting CBF, no significant differences were found between the sides in four regions of interest. After the ACZ challenge test, the CVR was significantly different between hemispheres (ipsilateral versus contralateral CVR: 12.9 ± 24.3% versus 28.0 ± 16.8%, respectively; p=0.005) and in the MCA territory (ipsilateral versus contralateral CVR: 8.7 ± 24.7% versus 29.3 ± 24%, respectively; p=0.003). However, no significant differences in CVR were detected between cortical comparisons and white matter comparisons from the two sides. Thus, ACZ-challenge Xe/CT is useful for the measurement of CBF and CVR in these patients. Impaired CVR is an important characteristic of patients with symptomatic MCA stenosis.
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Affiliation(s)
- Wenjie Cao
- Department of Neurology and Institute of Neurology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai 200040, China
| | - Xin Cheng
- Department of Neurology and Institute of Neurology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai 200040, China
| | - Haoxiong Li
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Liang Wang
- Department of Neurology and Institute of Neurology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai 200040, China
| | - Xiaolong Zhang
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Qiang Dong
- Department of Neurology and Institute of Neurology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai 200040, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.
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Abstract
Stroke is a serious healthcare problem with high mortality and long-term disability. However, to date, our ability to prevent and cure stroke remains limited. One important goal in stroke research is to identify the extent and location of lesion for treatment. In addition, accurately differentiating salvageable tissue from infarct and evaluating therapeutic efficacies are indispensible. These objectives could potentially be met with the assistance of modern neuroimaging techniques. This paper reviews current imaging methods commonly used in ischemic stroke research. These methods include positron emission tomography, computed tomography, T1 MRI, T2 MRI, diffusion and perfusion MRI, diffusion tensor imaging, blood-brain barrier permeability MRI, pH-weighted MRI, and functional MRI.
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Affiliation(s)
- Hsiao-Ying Wey
- University of Texas Health Science Center, San Antonio, Texas, USA
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Carlson AP, Yonas H. Radiographic assessment of vasospasm after aneurysmal subarachnoid hemorrhage: the physiological perspective. Neurol Res 2013; 31:593-604. [DOI: 10.1179/174313209x455754] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Sase S, Takahashi H, Shigefuku R, Ikeda H, Kobayashi M, Matsumoto N, Suzuki M. Measurement of blood flow and xenon solubility coefficient in the human liver by xenon-enhanced computed tomography. Med Phys 2013; 39:7553-9. [PMID: 23231303 DOI: 10.1118/1.4767759] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
PURPOSE The goal of this work was to develop a method of calculating blood flow and xenon solubility coefficient (λ) in the hepatic tissue by xenon-enhanced computed tomography (Xe-CT) and to demonstrate λ can be used as a measure of fat content in the human liver. METHODS A new blood supply model is introduced which incorporates both arterial blood and portal venous blood which join and together flow into hepatic tissue. We applied Fick's law to the model. It was theoretically derived that the time course of xenon concentration in the inflow blood (the mixture of the arterial blood and the portal venous blood) can be approximated by a monoexponential function. This approximation made it possible to obtain the time-course change rate (K(I)) of xenon concentration in the inflow blood using the time course of xenon concentration in the hepatic tissue by applying the algorithm we had reported previously. K(I) was used to calculate blood flow and λ for each pixel in the CT image of the liver. Twenty-six patients (49.2 ± 18.3 years) with nonalcoholic steatohepatitis underwent Xe-CT abdominal studies and liver biopsies. Steatosis of the liver was evaluated using the biopsy specimen and its severity was divided into ten grades according to the fat deposition percentage [(severity 1) ≤ 10%, 10 % <(severity 2) ≤ 20%, [ellipsis (horizontal)], 90% < (severity 10) ≤ 100%]. For each patient, blood flow and λ maps of the liver were created, and the average λ value (λ) was compared with steatosis severity and with the CT value ratio of the liver to the spleen (liver∕spleen ratio). RESULTS There were good correlations between λ and steatosis severity (r = 0.914, P < 0.0001), and between λ and liver∕spleen ratio (r = -0.881, P < 0.0001). Ostwald solubility for xenon in the hepatic tissue (tissue Xe solubility), which is calculated using λ and the hematocrit value of the patient, also showed a good correlation with steatosis severity (r = 0.910, P < 0.0001). λ ranged from 0.86 to 7.81, and tissue Xe solubility ranged from 0.12 to 1.16. This range of solubility is reasonable considering the reported Ostwald solubility coefficients for xenon in the normal liver and in the fat tissue are 0.10 and 1.3, respectively, at 37 °C. The average blood flow value ranged from 15.3 to 53.5 ml∕100 ml tissue∕min. CONCLUSIONS A method of calculating blood flow and λ in the hepatic tissue was developed by means of Xe-CT. This method would be valid even if portosystemic shunts exist; it is shown that λ maps can be used to deduce fat content in the liver. As a noninvasive modality, Xe-CT would be applicable to the quantitative study of fatty change in the human liver.
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Teo K, Choy DK, Lwin S, Ning C, Yeo TT, Shen L, Chong VF, Teoh HL, Seet RC, Chan BP, Sharma AK, Sharma VK. Cerebral Hyperperfusion Syndrome After Superficial Temporal Artery-middle Cerebral Artery Bypass for Severe Intracranial Steno-occlusive Disease: A Case Control Study. Neurosurgery 2013; 72:936-42; discussion 942-3. [DOI: 10.1227/neu.0b013e31828bb8b3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
BACKGROUND:
Intracranial stenoses carry increased risk for cerebral ischemia. We perform external carotid-internal carotid (EC-IC) artery bypass in our patients with severe stenosis of the intracranial internal carotid (ICA) or middle cerebral artery (MCA) with impaired cerebral vasodilatory reserve (CVR).
OBJECTIVE:
To evaluate cerebral hemodynamics and cerebral hyperperfusion syndrome (HPS) in patients who develop focal neurological deficits after EC-IC bypass surgery.
METHODS:
Patients with severe intracranial ICA or MCA stenosis and impaired CVR on transcranial Doppler (TCD) derived breath-holding index (BHI) were evaluated with acetazolamide-challenged technetium-99m hexamethylpropyleneamineoxime–single-photon emission computed tomography (SPECT). EC-IC bypass surgery was offered to patients with impaired CVR on SPECT. Close monitoring was performed in patients developing focal neurological deficits within 7 days of surgery.
RESULTS:
Of 112 patients with severe intracranial ICA/MCA stenosis, 77 (69%) showed impaired CVR and 46 (41%) underwent EC-IC bypass. Transient neurological deficits within 7 days of surgery developed in 8 (17%). HPS was confirmed by CT perfusion and/or SPECT in 7 cases. A strong correlation was observed between HPS and preoperative TCD-BHI values (0%, 6.3%, and 41% in patients with BHI 0.3-0.69, 0-0.3 and <0, respectively; P = .012). HPS patients showed more than a 50% increase in MCA flow velocity on TCD (compared with preoperative values) on the operated side (63.3% vs 3.3% on control side, P < .001). Meticulous control of blood pressure and hydration led to rapid and complete resolution of neurological deficits in all cases.
CONCLUSION:
Symptomatic cerebral HPS is common in the early postoperative period after EC-IC bypass surgery. Early diagnosis and appropriate management might prevent the complications of this syndrome.
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Affiliation(s)
- Kejia Teo
- Division of Neurosurgery, National University Hospital, Singapore
| | - David K.S. Choy
- Division of Neurosurgery, National University Hospital, Singapore
| | - Sein Lwin
- Division of Neurosurgery, National University Hospital, Singapore
| | - Chou Ning
- Division of Neurosurgery, National University Hospital, Singapore
| | - Tseng Tsai Yeo
- Division of Neurosurgery, National University Hospital, Singapore
| | - Liang Shen
- Division of Neurology, National University Hospital, Singapore
| | - Vincent F. Chong
- Department of Diagnostic Imaging, National University Hospital, Singapore
| | - Hock L. Teoh
- Division of Neurology, National University Hospital, Singapore
| | - Raymond C. Seet
- Division of Neurology, National University Hospital, Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | | | - Arvind K. Sharma
- Department of Diagnostic Imaging, National University Hospital, Singapore
| | - Vijay K. Sharma
- Division of Neurology, National University Hospital, Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Advanced imaging modalities in the detection of cerebral vasospasm. Neurol Res Int 2013; 2013:415960. [PMID: 23476766 PMCID: PMC3580927 DOI: 10.1155/2013/415960] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Accepted: 12/09/2012] [Indexed: 11/24/2022] Open
Abstract
The pathophysiology of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is complex and is not entirely understood. Mechanistic insights have been gained through advances in the capabilities of diagnostic imaging. Core techniques have focused on the assessment of vessel caliber, tissue metabolism, and/or regional perfusion parameters. Advances in imaging have provided clinicians with a multifaceted approach to assist in the detection of cerebral vasospasm and the diagnosis of delayed ischemic neurologic deficits (DIND). However, a single test or algorithm with broad efficacy remains elusive. This paper examines both anatomical and physiological imaging modalities applicable to post-SAH vasospasm and offers a historical background. We consider cerebral blood flow velocities measured by Transcranial Doppler Ultrasonography (TCD). Structural imaging techniques, including catheter-based Digital Subtraction Angiography (DSA), CT Angiography (CTA), and MR Angiography (MRA), are reviewed. We examine physiologic assessment by PET, HMPAO SPECT, 133Xe Clearance, Xenon-Enhanced CT (Xe/CT), Perfusion CT (PCT), and Diffusion-Weighted/MR Perfusion Imaging. Comparative advantages and limitations are discussed.
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27
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Xenon-inhalation computed tomography for noninvasive quantitative measurement of tissue blood flow in pancreatic tumor. Dig Dis Sci 2012; 57:801-5. [PMID: 21953140 DOI: 10.1007/s10620-011-1915-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 09/04/2011] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIMS The purpose of this prospective study was to demonstrate the ability to measure pancreatic tumor tissue blood flow (TBF) with a noninvasive method using xenon inhalation computed tomography (xenon-CT) and to correlate TBF with histological features, particularly microvascular density (MVD). METHODS TBFs of pancreatic tumors in 14 consecutive patients were measured by means of xenon-CT at diagnosis and following therapy. Serial abdominal CT scans were obtained before and after inhalation of nonradioactive xenon gas. TBF was calculated using the Fick principle. Furthermore, intratumoral microvessels were stained with anti-CD34 monoclonal antibodies before being quantified by light microscopy (×200). We evaluated MVD based on CD34 expression and correlated it with TBF. RESULTS The quantitative TBF of pancreatic tumors measured by xenon CT ranged from 22.3 to 111.4 ml/min/100 g (mean ± SD, 59.6 ± 43.9 ml/min/100 g). High correlation (r = 0.885, P < 0.001) was observed between TBF and intratumoral MVD. CONCLUSION Xenon-CT is feasible in patients with pancreatic tumors and is able to accurately estimate MVD noninvasively.
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Schubert GA, Seiz M, Czabanka M, Thomé C. Perfusion Characteristics in Chronic Cerebrovascular Insufficiency : An Anatomically and Clinically Oriented XeCT Analysis of Cerebrovascular Atherosclerotic Disease. Transl Stroke Res 2011; 3:122-9. [PMID: 24323758 DOI: 10.1007/s12975-011-0107-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 09/21/2011] [Accepted: 09/21/2011] [Indexed: 10/17/2022]
Abstract
Xenon-enhanced computed tomography (XeCT) allows quantification of hemodynamic insufficiency in the setting of cerebrovascular atherosclerotic disease (CAD). However, data regarding the relationship between hemodynamic indices [cerebral blood flow (CBF) and cerebrovascular reserve capacity (CVRC)] and normal subjects (with aging) and pathology (progression of CAD or development of stroke symptoms) are limited. In this study, we analyzed 103 consecutive patients undergoing XeCT according to age, anatomical location and disease severity. We stratified anatomically defined ROIs according to a classification system that observes the presence of proximal stenosis (class I vs. class II/III) as well as the presence of neurological symptoms (class II vs. III); CBF, CVRC and hemodynamic stress distribution were calculated. Supratentorial CBF decreases significantly with age, but not infratentorially. Cortical CVRC remains stable over time. Our classification of disease severity correlated highly significantly with a decrease in supratentorial CBF and CVRC, though CVRC is less sensitive to age-related changes. Regression analysis delineated a CVRC of 34% to discriminate between ROI classes. Age-dependent perfusion characteristics in normal vascular territories were characterized. In CAD, CVRC remains the most sensitive parameter. A simplified classification of ROIs according to disease severity correlates well with established markers for hemodynamic insufficiency. It may facilitate comparison of different pathologies such as CAD and Moyamoya disease and will be the focus of further studies.
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Mazzanti ML, Walvick RP, Zhou X, Sun Y, Shah N, Mansour J, Gereige J, Albert MS. Distribution of hyperpolarized xenon in the brain following sensory stimulation: preliminary MRI findings. PLoS One 2011; 6:e21607. [PMID: 21789173 PMCID: PMC3137603 DOI: 10.1371/journal.pone.0021607] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 06/03/2011] [Indexed: 11/18/2022] Open
Abstract
In hyperpolarized xenon magnetic resonance imaging (HP (129)Xe MRI), the inhaled spin-1/2 isotope of xenon gas is used to generate the MR signal. Because hyperpolarized xenon is an MR signal source with properties very different from those generated from water-protons, HP (129)Xe MRI may yield structural and functional information not detectable by conventional proton-based MRI methods. Here we demonstrate the differential distribution of HP (129)Xe in the cerebral cortex of the rat following a pain stimulus evoked in the animal's forepaw. Areas of higher HP (129)Xe signal corresponded to those areas previously demonstrated by conventional functional MRI (fMRI) methods as being activated by a forepaw pain stimulus. The percent increase in HP (129)Xe signal over baseline was 13-28%, and was detectable with a single set of pre and post stimulus images. Recent innovations in the production of highly polarized (129)Xe should make feasible the emergence of HP (129)Xe MRI as a viable adjunct method to conventional MRI for the study of brain function and disease.
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Affiliation(s)
- Mary L. Mazzanti
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ronn P. Walvick
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Xin Zhou
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Yanping Sun
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Lurie Family Imaging Center, Center for Biomedical Imaging in Oncology, Dana Farber Cancer Institute, Massachusetts, United States of America
| | - Niral Shah
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Joey Mansour
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jessica Gereige
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mitchell S. Albert
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada
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Tarr RW, Jungreis CA, Horton JA, Pentheny S, Sekhar LN, Sen C, Janecka IP, Yonas H. Complications of preoperative balloon test occlusion of the internal carotid arteries: experience in 300 cases. Skull Base Surg 2011; 1:240-4. [PMID: 17170842 PMCID: PMC1656333 DOI: 10.1055/s-2008-1057104] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Treatment of some tumors and aneurysms of the skull base may require internal carotid artery (ICA) sacrifice. Preoperatively to determine the dependence of the cerebral blood flow on a particular vessel, we perform a balloon test occlusion (BTO) by temporarily occluding the vessel in an awake patient. During occlusion, clinical evaluations and cerebral blood flow measurements are assessed. We have performed 300 BTOs. Eleven patients (3.7%) have had complications. Six (2%) were asymptomatic dissections. Five (1.7%) had neurologic deficits that persisted beyond the test period. Of these five, one was back to baseline in less than 24 hours, one recovered completely in a week, and one (0.33%) had a minimal but persistent dysphasia. These latter three cases are unexplained but might have resulted from unrecognized dissections or embolic events. Finally, one patient with a persistent deficit required energency surgery for reasons unrelated to the BTO and was therefore difficult to assess, and one required emergency middle cerebral artery embolectomy and repair of the dissection. The preoperative knowledge of carotid dependence in cases in which the ICA is at risk is essential, since vascular grafts or alternative surgical approaches are necessary in patients unable to tolerate carotid sacrifice. Since approximately 15 to 20% of the population falls into this category, a preoperative BTO appears justified.
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Carlson AP, Brown AM, Zager E, Uchino K, Marks MP, Robertson C, Sinson GP, Marmarou A, Yonas H. Xenon-enhanced cerebral blood flow at 28% xenon provides uniquely safe access to quantitative, clinically useful cerebral blood flow information: a multicenter study. AJNR Am J Neuroradiol 2011; 32:1315-20. [PMID: 21700787 DOI: 10.3174/ajnr.a2522] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Xe-CT measures CBF and can be used to make clinical treatment decisions. Availability has been limited, in part due to safety concerns. Due to improvements in CT technology, the concentration of inhaled xenon gas has been decreased from 32% to 28%. To our knowledge, no data exist regarding the safety profile of this concentration. We sought to better determine the safety profile of this lower concentration through a multicenter evaluation of adverse events reported by all centers currently performing xenon/CT studies in the US. MATERIALS AND METHODS Patients were prospectively recruited at 7 centers to obtain safety and efficacy information. All studies were performed to answer a clinical question. All centers used the same xenon delivery system. CT imaging was used during a 4.3-minute inhalation of 28% xenon gas. Vital signs were monitored on all patients throughout each procedure. Occurrence and severity of adverse events were recorded by the principal investigator at each site. RESULTS At 7 centers, 2003 studies were performed, 1486 (74.2%) in nonventilated patients. The most common indications were occlusive vascular disease and ischemic stroke; 93% of studies were considered clinically useful. Thirty-nine studies (1.9%) caused respiratory suppression of >20 seconds, all of which resolved spontaneously. Shorter respiratory pauses occurred in 119 (5.9%), and hyperventilation, in 34 (1.7%). There were 53 additional adverse events (2.9%), 7 of which were classified as severe. No adverse event resulted in any persistent neurologic change or other sequelae. CONCLUSIONS Xe-CT CBF can be performed safely, with a very low risk of adverse events and, to date, no risk of permanent morbidity or sequelae. On the basis of the importance of the clinical information gained, Xe-CT should be made widely available.
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Affiliation(s)
- A P Carlson
- Department of Neurosurgery, University of New Mexico, Albuquerque, New Mexico, USA
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Chaer RA, Shen J, Rao A, Cho JS, Abu Hamad G, Makaroun MS. Cerebral reserve is decreased in elderly patients with carotid stenosis. J Vasc Surg 2010; 52:569-74; discussion 574-5. [PMID: 20620003 DOI: 10.1016/j.jvs.2010.04.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2009] [Revised: 04/05/2010] [Accepted: 04/06/2010] [Indexed: 10/19/2022]
Abstract
OBJECTIVES Octogenarians and even patients over 70 years old have unexplained poor outcomes with carotid angioplasty and stenting (CAS). We sought to evaluate whether older patients may have compromised intracranial collaterals and cerebral reserve and be intolerant to otherwise clinically silent emboli generated during CAS. METHODS One thousand twenty-four cerebral blood flow (CBF) studies performed between 1991 and 2001 with stable xenon computed tomography scans (Xe/CT) were reviewed. CBF was measured before and after 1 gm intravenous acetazolamide (ACZ), a cerebral vasodilator. The normal response to ACZ is an increase in CBF. In areas of significant compromise of cerebral reserve (CR), CBF drops, representing a "steal" phenomenon. CBF changes were categorized as normal or abnormal and correlated with age, gender, cerebral symptoms, and with intracranial, carotid, or vertebral artery disease. Logistic regression was used to determine the effect of age on CR in the entire group and a subgroup of 179 patients with significant carotid stenosis of >50%. RESULTS Nine hundred sixteen studies were suitable for analysis. Carotid occlusion was predictive of decreased reserve (OR, 3.9; P = .03) regardless of age. There was also a trend toward lower reserve with severe carotid stenosis >70% (OR, 3) and in women (OR, 1.8; P = .08). Age >or=70 had no effect on reserve in the overall heterogeneous population with and without carotid disease and neither did a history of stroke, carotid, or intracranial stenosis. However, in 179 patients with significant carotid stenosis, age >or=70 was predictive of poor reserve (OR, 2.7; P = .03) and so was the presence of peripheral vascular disease (OR, 3.7; P = .03). A trend toward decreased reserve was also seen in women (OR, 2.3; P = .08). CONCLUSIONS Age >or=70 is associated with poor cerebral reserve in patients with significant carotid stenosis as measured by CBF response to an ACZ challenge. Thus, patients >or=70 may be more sensitive to minor cerebral emboli, which may be one factor explaining their higher risk of stroke during CAS.
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Affiliation(s)
- Rabih A Chaer
- University of Pittsburgh Medical Center, Division of Vascular Surgery, Pittsburgh, PA 15213, USA.
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Sase S, Nakano H, Suzuki H, Honda M. Subtraction lung image for evaluating pulmonary ventilation in xenon-enhanced CT. Med Phys 2010; 37:4464-74. [DOI: 10.1118/1.3464490] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Zaharchuk G, Straka M, Marks MP, Albers GW, Moseley ME, Bammer R. Combined arterial spin label and dynamic susceptibility contrast measurement of cerebral blood flow. Magn Reson Med 2010; 63:1548-56. [PMID: 20512858 PMCID: PMC2905651 DOI: 10.1002/mrm.22329] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Accepted: 11/18/2009] [Indexed: 11/07/2022]
Abstract
Dynamic susceptibility contrast (DSC) and arterial spin labeling (ASL) are both used to measure cerebral blood flow (CBF), but neither technique is ideal. Absolute DSC-CBF quantitation is challenging due to many uncertainties, including partial- volume errors and nonlinear contrast relaxivity. ASL can measure quantitative CBF in regions with rapidly arriving flow, but CBF is underestimated in regions with delayed arrival. To address both problems, we have derived a patient-specific correction factor, the ratio of ASL- and DSC-CBF, calculated only in short-arrival-time regions (as determined by the DSC-based normalized bolus arrival time [Tmax]). We have compared the combined CBF method to gold-standard xenon CT in 20 patients with cerebrovascular disease, using a range of Tmax threshold levels. Combined ASL and DSC CBF demonstrated quantitative accuracy as good as the ASL technique but with improved correlation in voxels with long Tmax. The ratio of MRI-based CBF to xenon CT CBF (coefficient of variation) was 90 +/- 30% (33%) for combined ASL and DSC CBF, 43 +/- 21% (47%) for DSC, and 91 +/- 31% (34%) for ASL (Tmax threshold 3 sec). These findings suggest that combining ASL and DSC perfusion measurements improves quantitative CBF measurements in patients with cerebrovascular disease.
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Affiliation(s)
- Greg Zaharchuk
- Department of Radiology, Stanford University, Stanford, California 94305-5488, USA.
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Zaharchuk G, Bammer R, Straka M, Newbould RD, Rosenberg J, Olivot JM, Mlynash M, Lansberg MG, Schwartz NE, Marks MM, Albers GW, Moseley ME. Improving dynamic susceptibility contrast MRI measurement of quantitative cerebral blood flow using corrections for partial volume and nonlinear contrast relaxivity: A xenon computed tomographic comparative study. J Magn Reson Imaging 2009; 30:743-52. [PMID: 19787719 DOI: 10.1002/jmri.21908] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To test whether dynamic susceptibility contrast MRI-based CBF measurements are improved with arterial input function (AIF) partial volume (PV) and nonlinear contrast relaxivity correction, using a gold-standard CBF method, xenon computed tomography (xeCT). MATERIALS AND METHODS Eighteen patients with cerebrovascular disease underwent xeCT and MRI within 36 h. PV was measured as the ratio of the area under the AIF and the venous output function (VOF) concentration curves. A correction was applied to account for the nonlinear relaxivity of bulk blood (BB). Mean CBF was measured with both techniques and regression analyses both within and between patients were performed. RESULTS Mean xeCT CBF was 43.3 +/- 13.7 mL/100g/min (mean +/- SD). BB correction decreased CBF by a factor of 4.7 +/- 0.4, but did not affect precision. The least-biased CBF measurement was with BB but without PV correction (45.8 +/- 17.2 mL/100 g/min, coefficient of variation [COV] = 32%). Precision improved with PV correction, although absolute CBF was mildly underestimated (34.3 +/- 10.8 mL/100 g/min, COV = 27%). Between patients correlation was moderate even with both corrections (R = 0.53). CONCLUSION Corrections for AIF PV and nonlinear BB relaxivity improve bolus MRI-based CBF maps. However, there remain challenges given the moderate between-patient correlation, which limit diagnostic confidence of such measurements in individual patients.
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Affiliation(s)
- Greg Zaharchuk
- Department of Radiology, Stanford University, Stanford, California, USA.
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Przybylski GJ, Yonas H, Smith HA. Reduced stroke risk in patients with compromised cerebral blood flow reactivity treated with superficial temporal artery to distal middle cerebral artery bypass surgery. J Stroke Cerebrovasc Dis 2009; 7:302-9. [PMID: 17895105 DOI: 10.1016/s1052-3057(98)80047-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/1997] [Accepted: 04/22/1998] [Indexed: 11/29/2022] Open
Abstract
UNLABELLED Extracranial-to-intracranial (EC-IC) bypass surgery for the prevention of stroke in patients with symptomatic carotid artery occlusion has nearly ended after a randomized trial showed no benefit of the procedure. Although an EC-IC bypass might benefit patients with compromised cerebrovascular hemodynamics, the randomized trial did not differentiate patients with hemodynamic from embolic etiologies. However, subsequent investigators have identified a subgroup of patients at increased stroke risk from hemodynamic compromise. METHODS We examined the subsequent stroke rate of 42 patients with symptomatic carotid occlusion at high risk for stroke identified as having a baseline cerebral blood flow (CBF)<45 mL/100 g/min and a >5% CBF reduction in one vascular territory after a vasodilatory challenge from 1 g of intravenous acetazolamide on stable xenon-computed tomography (CT) CBF imaging. RESULTS Thirty patients (group 1) treated medically were a subgroup with carotid occlusion from our long-term natural history study. During a median follow-up of 12 months, 9 patients (30%) had a new stroke within a median of 5 months. Twelve patients (group 2) had recurrent, disabling cerebral ischemic symptoms, with 8 progressing to mild fixed neurological deficits from deep white matter infarction identified on CT. All were treated with superficial temporal artery to distal middle cerebral artery (STA-MCA) bypass with restoration of cerebrovascular reserve postoperatively; none had a stroke during the 18-month minimum follow-up (P=.041). Perioperative morbidity included subendocardial infarction in one and a small, asymptomatic left frontal hemorrhage in another patient. Early postoperative and delayed xenon/CT CBF studies obtained a median of 5 months postoperatively showed maintenance of cerebrovascular reserve. CONCLUSION STA-MCA bypass surgery can restore cerebrovascular reserve in high-risk patients with symptomatic internal carotid artery occlusion. This was achieved with minimal perioperative complications, resulting in a subsequent reduction of stroke frequency. We suggest that the efficacy of STA-MCA bypass surgery for symptomatic carotid occlusion be re-examined prospectively using hemodynamic selection criteria.
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Affiliation(s)
- G J Przybylski
- Department of Neurological Surgery, The University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Takahashi H, Suzuki M, Ikeda H, Kobayashi M, Sase S, Yotsuyanagi H, Maeyama S, Iino S, Itoh F. Evaluation of quantitative portal venous, hepatic arterial, and total hepatic tissue blood flow using xenon CT in alcoholic liver cirrhosis-comparison with liver cirrhosis related to hepatitis C virus and nonalcoholic steatohepatitis. Alcohol Clin Exp Res 2009; 34 Suppl 1:S7-S13. [PMID: 18986379 DOI: 10.1111/j.1530-0277.2008.00755.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND/AIMS Xenon computed tomography (Xe-CT) is a noninvasive method of quantifying and visualizing tissue blood flow (TBF). For the liver, Xe-CT allows separate measurement of hepatic arterial and portal venous TBF. The present study evaluated the usefulness of Xe-CT as a noninvasive diagnostic procedure for measuring hepatic TBF in alcoholic liver cirrhosis (AL-LC), compared with liver cirrhosis related to nonalcoholic steatohepatitis (NASH), (NASH-LC), and hepatitis C virus (HCV), (C-LC). METHODS Xe-CT was performed on 22 patients with AL-LC, 7 patients with NASH-LC, and 24 patients with C-LC. Severity of LC was classified according to Child-Pugh classification. Correlations between hepatic TBF, Child-Pugh classification, and indocyanin green retention (ICG) rate after 15 minutes (ICG15R) were examined. Correlations of hepatic TBF in Child-Pugh class A to AL-LC, NASH-LC, and C-LC were also examined. RESULTS Portal venous TBF (PVTBF) displayed a significant negative correlation with Child-Pugh score and ICG15R (r = -0.432, p < 0.01, r = -0.442, p < 0.01, respectively). Moreover, ICG15R displayed a significant positive correlation with Child-Pugh score (r = 0.661, p < 0.001). Meanwhile, mean PVTBF and total hepatic TBF (THTBF) was significantly lower in AL-LC than in C-LC (p < 0.05). Mean PVTBF was significantly lower in Child-Pugh class A to AL-LC and NASH-LC than in that to C-LC (p < 0.05). Similarly, mean THTBF was significantly lower in Child-Pugh class A to NASH-LC than in that to C-LC (p < 0.05). CONCLUSIONS Measurement of hepatic TBF using Xe-CT is useful as a noninvasive, objective method of assessing the state of the liver in chronic liver disease.
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Affiliation(s)
- Hideaki Takahashi
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University, School of Medicine, 2-16-1 Sugao Miyamaeku, Kawasaki, 216-8511, Japan.
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Kobayashi M, Suzuki M, Ikeda H, Takahashi H, Matsumoto N, Maeyama S, Sase S, Iino S, Itoh F. Assessment of hepatic steatosis and hepatic tissue blood flow by xenon computed tomography in nonalcoholic steatohepatitis. Hepatol Res 2009; 39:31-9. [PMID: 18761681 DOI: 10.1111/j.1872-034x.2008.00407.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
AIM The diagnosis of non-alcoholic steatohepatitis (NASH) can be difficult using blood tests and imaging studies. Histological diagnosis by liver biopsy remains the gold standard of NASH diagnosis. There is an urgent need to develop and validate simple, reproducible, noninvasive tests to accurately assess NASH stage and grade. We assess the usefulness of xenon computed tomography (Xe-CT), as a non-invasive method of quantitatively and visually determining hepatic tissue blood flows (TBFs), and xenon solubility (lambda value) simultaneously with TBF, in the evaluation of NASH pathophysiology. METHODS Histological severity of fatty changes and severity of fibrosis based on Brunt's classification were determined in 38 NASH patients. We evaluated correlations between the grade of fatty changes and lambda value, and correlations between the stage of fibrosis and TBFs. RESULTS The lambda value showed significant positive correlations with both grade of steatosis (r = 0.813, P < 0.001) and each 10% range of histological fatty infiltration (r = 0.926, P < 0.001). A significant negative correlation was seen between lambda value and the liver : spleen ratio (r = -0.835, P < 0.001). Portal venous tissue blood flow and total hepatic tissue blood flow showed significant negative correlations with the progression of fibrosis (r = -0.465, P < 0.01; r = -0.433, P < 0.01, respectively). Total hepatic tissue blood flow tended to decrease with progressing grade of steatosis. CONCLUSION Xe-CT offers a convenient and objective method for evaluating fatty infiltration and changes in blood flow in the entire liver, and appears useful for detailed evaluation of patients with NASH.
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Affiliation(s)
- Minoru Kobayashi
- Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kawasaki, Japan
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Sase S, Takahashi H, Ikeda H, Kobayashi M, Matsumoto N, Suzuki M. Determination of time-course change rate for arterial xenon using the time course of tissue xenon concentration in xenon-enhanced computed tomography. Med Phys 2008; 35:2331-8. [PMID: 18649466 DOI: 10.1118/1.2912021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In calculating tissue blood flow (TBF) according to the Fick principle, time-course information on arterial tracer concentration is indispensable and has a considerable influence on the accuracy of calculated TBF. In TBF measurement by xenon-enhanced computed tomography (Xe-CT), nonradioactive xenon gas is administered by inhalation as a tracer, and end-tidal xenon is used as a substitute for arterial xenon. There has been the assumption that the time-course change rate for end-tidal xenon concentration (Ke) and that for arterial xenon concentration (Ka) are substantially equal. Respiratory gas sampling is noninvasive to the patient and Ke can be easily measured by exponential curve fitting to end-tidal xenon concentrations. However, it is pointed out that there would be a large difference between Ke and Ka in many cases. The purpose of this work was to develop a method of determining the Ka value using the time course of tissue xenon concentration in Xe-CT. The authors incorporated Ka into the Kety autoradiographic equation as a parameter to be solved, and developed a method of least-squares to obtain the solution for Ka from the time-course changes in xenon concentration in the tissue. The authors applied this method of least-squares to the data from Xe-CT abdominal studies performed on 17 patients; the solution for Ka was found pixel by pixel in the spleen, and its Ka map was created for each patient. On the one hand, the authors obtained the average value of the Ka map of the spleen as the calculated Ka (Ka(calc)) for each patient. On the other hand, the authors measured Ka (Ka(meas)) using the time-course changes in CT enhancement in the abdominal aorta for each patient. There was a good correlation between Ka(calc), and Ka(meas) (r = 0.966, P < 0.0001), and these two Ka values were close to each other (Ka(calc) = 0.935 x Ka(meas) + 0.089). This demonstrates that K(cala) would be close to the true Ka value. Accuracy of TBF by Xe-CT can be improved with use of the average value of the Ka map of an organ like the spleen that has a single blood supply (only arterial inflow).
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Affiliation(s)
- Shigeru Sase
- Anzai Medical Co., Ltd., 3-9-15 Nishi-Shinagawa, Shinagawa-ku, Tokyo 141-0033, Japan.
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Schubert GA, Weinmann C, Seiz M, Gerigk L, Weiss C, Horn P, Thomé C. Cerebrovascular insufficiency as the criterion for revascularization procedures in selected patients: a correlation study of xenon contrast-enhanced CT and PWI. Neurosurg Rev 2008; 32:29-35; discussion 35-6. [PMID: 18791753 DOI: 10.1007/s10143-008-0159-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Revised: 03/18/2008] [Accepted: 06/29/2008] [Indexed: 12/29/2022]
Abstract
In order to identify patients who suffer from hemodynamic cerebral insufficiency and can benefit from cerebral revascularization procedures, xenon-CT scanning has been established to reliably measure the critical cerebrovascular reserve capacity. As a need for alternative quantification methods arises, this study aims to characterize the significance of both time-to-peak (TTP) and mean transit time (MTT) in perfusion-weighted imaging (PWI) in this particular subset of patients. Ten patients in routine preoperative work-up for cerebral revascularization were prospectively enrolled and underwent both XeCT scanning and PWI. Cerebrovascular reserve capacity (CVRC) was calculated for each region of interest (ROI, n = 504) after administration of a vasoactive stimulus. ROIs were anatomically matched with those of PWI after TTP and MTT were calculated. Highly significant negative correlation was found for TTP and CVRC for all ROIs (r = -0.3954, p < 0.0001; symptomatic ROIs: r = -0.4867, p < 0.0001). Correlation was weak for MTT and CVCR (r = -0.1287; p < 0.01). The optimum threshold for TTP to detect impaired cerebrovascular reactivity in our patient group was 4 s (specificity 90.8%, sensitivity 44.4%) for all ROIs (TTP > 4.4 s for symptomatic ROIs, specificity 88.4%, sensitivity 62.7%). An approximative equation to calculate the probability of pathological findings could be derived from the data. The positive predictive value (PPV) was 0.76 (symptomatic 0.78) with a negative predictive value (NPV) of 0.71 (symptomatic 0.78). While PWI currently is not able to replace XeCT in the direct quantification of CVRC, it may serve as a readily available follow-up tool. A TTP threshold of greater than 4 s allows to confirm a cerebrovascular compromise in a selected high-risk subgroup of patients.
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Takahashi H, Suzuki M, Ikeda H, Kobayashi M, Sase S, Yotsuyanagi H, Maeyama S, Iino S, Itoh F. Evaluation of quantitative portal venous, hepatic arterial, and total hepatic tissue blood flow using xenon CT in alcoholic liver cirrhosis: comparison with liver cirrhosis C. Alcohol Clin Exp Res 2008; 31:S43-8. [PMID: 17331165 DOI: 10.1111/j.1530-0277.2006.00285.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND/AIMS Xenon computed tomography (Xe-CT) is a noninvasive method of quantifying and visualizing tissue blood flow (TBF). For the liver, Xe-CT allows separate measurement of hepatic arterial and portal venous TBF. The present study evaluated the usefulness of Xe-CT as a noninvasive diagnostic procedure for measuring hepatic TBF in alcoholic liver cirrhosis (AL-LC), compared with liver cirrhosis C (C-LC). METHODS Xenon computed tomography was performed on 12 patients with AL-LC and 17 patients with C-LC. The severity of LC was classified according to Child-Pugh classification. Correlations between hepatic TBF and Child-Pugh classification were examined. Correlations of hepatic TBF in Child-Pugh class A to C-LC and AL-LC were also examined. RESULTS The mean portal venous TBF (PVTBF) was significantly lower in AL-LC than in C-LC (p=0.0316). Similarly, the mean total hepatic TBF (THTBF) was significantly lower in AL-LC than in C-LC (p=0.0390). PVTBF displayed a significant negative correlation with Child-Pugh score (r=-0.396, p=0.0368). CONCLUSIONS Measurement of hepatic TBF using Xe-CT is useful as a noninvasive, objective method of assessing the state of the liver in chronic liver disease.
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Affiliation(s)
- Hideaki Takahashi
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, St. Marianna University, School of Medicine, Kawasaki, Japan
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Ikeda H, Suzuki M, Kobayashi M, Takahashi H, Matsumoto N, Maeyama S, Iino S, Sase S, Itoh F. Xenon computed tomography shows hemodynamic change during the progression of chronic hepatitis C. Hepatol Res 2007; 37:104-12. [PMID: 17300705 DOI: 10.1111/j.1872-034x.2007.00020.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
AIM Xenon computed tomography (Xe-CT) is a non-invasive method of quantifying and visualizing tissue blood flow (TBF). Xe-CT allows separate measurement of hepatic arterial and portal venous flow. The aim of this study was to investigate correlations between the progression of fibrosis and hemodynamic changes in chronic hepatitis C (CHC) patients using Xe-CT. METHODS Separate measurements of portal venous TBF (PVTBF) and hepatic arterial TBF (HATBF) were performed using Xe-CT, and total hepatic TBF (THTBF) was calculated as the sum of PVTBF and HATBF. A total of 50 patients with CHC underwent Xe-CT. Liver biopsy was performed on 42 of the 50 patients, and hepatic fibrosis was classified as mild (F1), moderate (F2), severe (F3) or Child-Pugh class A cirrhosis (F4a). In addition, eight patients with Child-Pugh class B cirrhosis (F4b) were evaluated. RESULTS Significant negative correlations were identified between PVTBF and progression of stage (r(s) = -0.622, P < 0.0001) and between THTBF and progression of stage (r(s) = -0.458, P = 0.0041). CONCLUSION Separate measurement of PVTBF and HATBF using non-invasive Xe-CT provided quantitative and visual information regarding hemodynamics of the entire liver in CHC patients. PVTBF decreases with the progression of fibrosis, even in CHC patients.
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Affiliation(s)
- Hiroki Ikeda
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, St. Marianna University, School of Medicine, Kawasaki, Japan
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Tayal AH, Gupta R, Yonas H, Jovin T, Uchino K, Hammer M, Wechsler L, Gebel JM. Quantitative perihematomal blood flow in spontaneous intracerebral hemorrhage predicts in-hospital functional outcome. Stroke 2006; 38:319-24. [PMID: 17194883 DOI: 10.1161/01.str.0000254492.35504.db] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Few data on xenon computed tomography-based quantitative cerebral blood flow (CBF) in spontaneous intracerebral hemorrhage have been reported. We correlated perihematomal CBF in a retrospective series of 42 subacute spontaneous intracerebral hemorrhage patients undergoing xenon computed tomography with in-hospital discharge status and mortality. METHODS We calculated 3 area-weighted mean CBF values: (1) within the computed tomography-visible rim of perihematomal edema, (2) within a 1-cm marginal radius around the hematoma, and (3) all cortical regions of interest immediately adjacent to the hematoma. Primary outcomes were in-hospital mortality and discharge status (ordinally as 0=home, 1=acute rehabilitation, 2=nursing home, 3=death). Discharge status was used as a surrogate for in-hospital functional outcome. RESULTS Median hematoma volume was 14.4 cm(3) (range, 2 to 70). Median perihematomal (low-attenuation rim) CBF was 21.9 cm(3).100 g(-1).min(-1) (range, 6.1 to 81.1), and the median 1-cm marginal radius CBF was 26.8 cm(3).100 g(-1).min(-1) (range, 10.8 to 72.8). The median regional cortical CBF was 26.7 cm(3).100 g(-1).min(-1) (range, 6.9 to 72.6). Eight patients had 1-cm marginal radius or regional cortical CBF values <20 cm(3).100 g(-1).min(-1). Hematoma volume (odds ratio [OR], 1.68 per 10-cm(3) volume; P=0.036) and intraventricular hemorrhage (OR, 1.88 per grade of intraventricular hemorrhage; P=0.036) predicted mortality. Two CBF measures, hydrocephalus, and IVH predicted poor in-hospital functional outcome in bivariate analysis. Each CBF measure (OR, 0.34 to 0.43; P<0.001 to 0.003) and intraventricular hemorrhage (OR, 3.42; P<0.001) predicted in-hospital functional outcome in multivariable analyses. CONCLUSIONS Most spontaneous intracerebral hemorrhage patients lack perihematomal penumbra. Perihematomal CBF independently predicts in-hospital discharge status but not in-hospital mortality. Further studies are warranted to determine whether perihematomal CBF predicts long-term functional outcomes.
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Affiliation(s)
- Ashis H Tayal
- Department of Neurology and University of Pittsburgh Medical Center Stroke Institute, University of Pittsburgh, Pittsburgh, PA, USA
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Prasad PV. Functional MRI of the kidney: tools for translational studies of pathophysiology of renal disease. Am J Physiol Renal Physiol 2006; 290:F958-74. [PMID: 16601297 PMCID: PMC2919069 DOI: 10.1152/ajprenal.00114.2005] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Magnetic resonance imaging (MRI) provides exquisite anatomic detail of various organs and is capable of providing additional functional information. This combination allows for comprehensive diagnostic evaluation of pathologies such as ischemic renal disease. Noninvasive MRI techniques could facilitate translation of many studies performed in controlled animal models using technologies that are invasive to humans. Such a translation is being recognized as essential because many proposed interventions and drugs that prove efficacious in animal models fail to do so in humans. In this article, we review the state-of-the-art functional MRI technique as applied to the kidneys.
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Affiliation(s)
- Pottumarthi V Prasad
- Dept. of Radiology, Walgreen Jr. Bldg., Suite 507, Evanston Northwestern Healthcare, 2650 Ridge Ave., Evanston, IL 60201, USA.
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45
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Abstract
Acute stroke therapy is evolving rapidly as research moves toward extending the time window for treatment so that more patients can benefit. As physiology-based imaging increasingly is used in patient selection, it is becoming evident that rigid time windows are not applicable to individual patients. Xenon CT has an important role in acute stroke therapeutic intervention as a quantitative, reproducible, rapid, and safe modality, which can provide valuable physiologic data that can optimize patient triage and aid in management.
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Affiliation(s)
- Rishi Gupta
- Department of Neurology, Stroke Institute, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
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46
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Wintermark M, Sesay M, Barbier E, Borbély K, Dillon WP, Eastwood JD, Glenn TC, Grandin CB, Pedraza S, Soustiel JF, Nariai T, Zaharchuk G, Caillé JM, Dousset V, Yonas H. Comparative overview of brain perfusion imaging techniques. J Neuroradiol 2006; 32:294-314. [PMID: 16424829 DOI: 10.1016/s0150-9861(05)83159-1] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Numerous imaging techniques have been developed and applied to evaluate brain hemodynamics. Among these are: Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), Xenon-enhanced Computed Tomography (XeCT), Dynamic Perfusion-computed Tomography (PCT), Magnetic Resonance Imaging Dynamic Susceptibility Contrast (DSC), Arterial Spin-Labeling (ASL), and Doppler Ultrasound. These techniques give similar information about brain hemodynamics in the form of parameters such as cerebral blood flow (CBF) or volume (CBV). All of them are used to characterize the same types of pathological conditions. However, each technique has its own advantages and drawbacks. This article addresses the main imaging techniques dedicated to brain hemodynamics. It represents a comparative overview, established by consensus among specialists of the various techniques. For clinicians, this paper should offers a clearer picture of the pros and cons of currently available brain perfusion imaging techniques, and assist them in choosing the proper method in every specific clinical setting.
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Affiliation(s)
- M Wintermark
- Department of Radiology, Neuroradiology Section, University of California, 505 Parnassus Avenue, Room L358, Box 0628, San Francisco, CA 94143-0628, USA.
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47
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Ohashi M, Tsuji A, Kaneko M, Matsuda M. Threshold of regional cerebral blood flow for infarction in patients with acute cerebral ischemia. J Neuroradiol 2006; 32:337-41. [PMID: 16424835 DOI: 10.1016/s0150-9861(05)83165-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Threshold of regional cerebral blood flow (rCBF) for cerebral tissue survival in relation to time was studied in patients with acute cerebral ischemia with xenon-enhanced computed tomography (XeCT). Case 1: A 58-year-old man with right hemiparesis, total aphasia and a high intensity area of 1 cm 2 in the left insula on diffusion weighted image underwent XeCT CBF study before and after intra-arterial local thrombolytic therapy (IALT) on the occluded middle cerebral artery (MCA) 4 hours and 7 hours after stroke onset, respectively. Case 2: A 65-year-old woman with recurrent transient ischemic attacks (TIAs) caused by severe stenosis of the left MCA underwent XeCT CBF study 5 hours after onset of the last attack. XeCT was conducted by 5-min wash-in method. In Case 1 the rCBF in the pre-IALT MCA territory was 4 to 19 ml/100 g/min. The area where rCBF in the post-IALT increased to above 15 ml/100g/min were saved, but the other area where it remained in the 9 to 14 ml/100 g/min evolved into infarct on subsequent CT scan/MR (magnetic resonance) imaging. The patient was discharged with only mild motor dysphasia. In Case 2 the left corona radiata showed rCBF of 7 ml/100 g/min and this area evolved into infarct on MR imaging. The patient was discharged home with right hemiparesis. Our results showed validity of the rCBF threshold in acute cerebral ischemia reported by Jones et al. Residual rCBF in the acute stage of cerebral ischemic stroke can predict the fate of the lesion.
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Affiliation(s)
- M Ohashi
- Department of Neurosurgery, Shiga University of Medical Science, Ohtsu, Shiga 520-2192, Japan.
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48
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Wintermark M, Sesay M, Barbier E, Borbély K, Dillon WP, Eastwood JD, Glenn TC, Grandin CB, Pedraza S, Soustiel JF, Nariai T, Zaharchuk G, Caillé JM, Dousset V, Yonas H. Comparative overview of brain perfusion imaging techniques. Stroke 2005; 36:e83-99. [PMID: 16100027 DOI: 10.1161/01.str.0000177884.72657.8b] [Citation(s) in RCA: 295] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Numerous imaging techniques have been developed and applied to evaluate brain hemodynamics. Among these are positron emission tomography, single photon emission computed tomography, Xenon-enhanced computed tomography, dynamic perfusion computed tomography, MRI dynamic susceptibility contrast, arterial spin labeling, and Doppler ultrasound. These techniques give similar information about brain hemodynamics in the form of parameters such as cerebral blood flow or cerebral blood volume. All of them are used to characterize the same types of pathological conditions. However, each technique has its own advantages and drawbacks. SUMMARY OF REVIEW This article addresses the main imaging techniques dedicated to brain hemodynamics. It represents a comparative overview established by consensus among specialists of the various techniques. CONCLUSIONS For clinicians, this article should offer a clearer picture of the pros and cons of currently available brain perfusion imaging techniques and assist them in choosing the proper method for every specific clinical setting.
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Affiliation(s)
- Max Wintermark
- Department of Radiology, University of California, 505 Parnassus Ave, San Francisco, CA 94143-0628, USA.
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Sase S, Honda M, Machida K, Seiki Y. Comparison of cerebral blood flow between perfusion computed tomography and xenon-enhanced computed tomography for normal subjects: territorial analysis. J Comput Assist Tomogr 2005; 29:270-7. [PMID: 15772551 DOI: 10.1097/01.rct.0000156400.40836.68] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The purpose of this study was to clarify the difference between cerebral blood flow (CBF) by perfusion computed tomography (CT) and that by xenon-enhanced CT (Xe-CT) through simultaneous measurement. METHODS Xenon-enhanced CT and perfusion CT were continually performed on 7 normal subjects. Ratios of CBF by perfusion CT (P-CBF) to CBF by Xe-CT (Xe-CBF) were measured for 5 arterial territories; 3 were territories of 3 major arteries (the anterior [ACA], middle [MCA], and posterior [PCA] cerebral arteries), and the other 2 were areas of the thalamus and putamen. RESULTS The ratios were 1.30 +/- 0.10, 1.26 +/- 0.15, 1.61 +/- 0.15, 0.801 +/- 0.087, and 0.798 +/- 0.080 for the ACA, MCA, PCA, thalamus, and putamen, respectively. Although a good correlation was observed between P-CBF and Xe-CBF for each territory, the ratios were significantly different (P < 0.0001) between 3 territory groups (group 1: ACA and MCA, group 2: PCA, and group 3: thalamus and putamen). CONCLUSIONS The difference in the ratio of P-CBF to Xe-CBF between the 3 territory groups was considered to result principally from the features of P-CBF. To evaluate P-CBF properly, its territorial characteristics should be taken into account.
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50
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Harrod CG, Bendok BR, Batjer HH. Prediction of Cerebral Vasospasm in Patients Presenting with Aneurysmal Subarachnoid Hemorrhage: A Review. Neurosurgery 2005; 56:633-54; discussion 633-54. [PMID: 15792502 DOI: 10.1227/01.neu.0000156644.45384.92] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2004] [Accepted: 01/07/2005] [Indexed: 12/20/2022] Open
Abstract
Abstract
OBJECTIVE:
Cerebral vasospasm is a devastating medical complication of aneurysmal subarachnoid hemorrhage (SAH). It is associated with high morbidity and mortality rates, even after the aneurysm has been treated. A substantial amount of experimental and clinical research has been conducted in an effort to predict and prevent its occurrence. This research has contributed to significant advances in the understanding of the mechanisms leading to cerebral vasospasm. The ability to accurately and consistently predict the onset of cerebral vasospasm, however, has been challenging. This topic review describes the various methodologies and approaches that have been studied in an effort to predict the occurrence of cerebral vasospasm in patients presenting with SAH.
METHODS:
The English-language literature on the prediction of cerebral vasospasm after aneurysmal SAH was reviewed using the MEDLINE PubMed (1966–present) database.
RESULTS:
The risk factors, diagnostic imaging, bedside monitoring approaches, and pathological markers that have been evaluated to predict the occurrence of cerebral vasospasm after SAH are presented.
CONCLUSION:
To date, a large blood burden is the only consistently demonstrated risk factor for the prediction of cerebral vasospasm after SAH. Because vasospasm is such a multifactorial problem, attempts to predict its occurrence will probably require several different approaches and methodologies, as is done at present. Future improvements in the prevention of cerebral vasospasm from aneurysmal SAH will most likely require advances in our understanding of its pathophysiology and our ability to predict its onset.
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Affiliation(s)
- Christopher G Harrod
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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