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Hamami A, Aljamal M, Almuqbil N, Al-Harbi M, Hamd ZY. Assessment of Spectral Computed Tomography Image Quality and Detection of Lesions in the Liver Based on Image Reconstruction Algorithms and Virtual Tube Voltage. Diagnostics (Basel) 2025; 15:1043. [PMID: 40310426 PMCID: PMC12025537 DOI: 10.3390/diagnostics15081043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2025] [Revised: 04/07/2025] [Accepted: 04/15/2025] [Indexed: 05/02/2025] Open
Abstract
Background: Spectral detector computed tomography (SDCT) has demonstrated superior diagnostic performance and image quality in liver disease assessment compared with traditional CT. Selecting the right reconstruction algorithm and tube voltage is essential to avoid increased noise and diagnostic errors. Objectives: This study evaluated improvements in image quality achieved using various virtual tube voltages and reconstruction algorithms for diagnosing common liver diseases with spectral CT. Methods: This retrospective study involved forty-seven patients who underwent spectral CT scans for liver conditions, including fatty liver, hemangiomas, and metastatic lesions. The assessment utilized signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), with images reconstructed using various algorithms (IMR, iDose) at different levels and virtual tube voltages. Three experienced radiologists analyzed the reconstructed images to identify the best reconstruction methods and tube voltage combinations for diagnosing these liver pathologies. Results: The signal-to-noise ratio (SNR) was highest for spectral CT images using the IMR3 algorithm in metastatic, hemangioma, and fatty liver cases. A strong positive correlation was found between IMR3 at 120 keV and 70 keV (p-value = 0.000). In contrast, iDOSE2 at 120 keV and 70 keV showed a low correlation of 0.291 (p-value = 0.045). Evaluators noted that IMR1 at 70 keV provided the best visibility for liver lesions (mean = 3.58), while IMR3 at 120 keV had the lowest image quality (mean = 2.65). Conclusions: Improvements in image quality were noted with SDCT, especially in SNR values for liver tissues at low radiation doses and a specific IMR level. The IMR1 algorithm reduced noise, enhancing the visibility of liver lesions for better diagnosis.
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Affiliation(s)
- Areej Hamami
- Department of Medical Imaging, Faculty of Allied Medical Sciences, Arab American University, 13 Zababdeh, Jenin P.O. Box 240, Palestine;
| | - Mohammad Aljamal
- Department of Medical Imaging, Faculty of Allied Medical Sciences, Arab American University, 13 Zababdeh, Jenin P.O. Box 240, Palestine;
| | - Nora Almuqbil
- Department of Radiological Sciences, College of Health and Rehabilitation Sciences, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia; (N.A.); (Z.Y.H.)
| | - Mohammad Al-Harbi
- Medical Imaging Department, King Abdullah bin Abdulaziz University Hospital, P.O. Box 47330, Riyadh 11552, Saudi Arabia;
| | - Zuhal Y. Hamd
- Department of Radiological Sciences, College of Health and Rehabilitation Sciences, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia; (N.A.); (Z.Y.H.)
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Cuellar-Calabria H, Burcet G, Juarez-Garcia MS, Reyes-Juárez JL, Pizzi MN, Aguadé-Bruix S, Roque A. Implementing a coronary CT angiography protocol based on the body mass index: Radiation dose reduction, image quality, and diagnostic performance. RADIOLOGIA 2024; 66:2-12. [PMID: 38365351 DOI: 10.1016/j.rxeng.2022.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/28/2022] [Indexed: 02/18/2024]
Abstract
OBJECTIVES To evaluate the relation between the coronary calcium score and the posterior choice of kilovoltage according to radiologists' criteria in a standard coronary CT angiography protocol to rule out coronary disease. To quantify the reduction in ionizing radiation after linking kilovoltage to patients' body mass index in a low-dose protocol with iterative model reconstruction. To evaluate the image quality and diagnostic performance of the low-dose protocol. MATERIAL AND METHODS We compared anthropometric characteristics, calcium score, kilovoltage levels, size-specific dose estimates (SSDE), and the dose-length product (DLP) between a group of 50 patients who were prospectively recruited to undergo coronary CT angiography with a low-dose protocol and a historical group of 50 patients who underwent coronary CT angiography with the standard protocol. We correlated these parameters, the number of coronary segments that could not be evaluated with and without temporal padding, the attenuation, and the signal-to-noise ratio in the ascending aorta in the low-dose protocol with excellent imaging quality according to a semiquantitative scale. To calculate the diagnostic performance per patient, we used 24-month clinical follow-up including all tests as the gold standard. RESULTS In the standard protocol, the presence of coronary calcium correlated with the selection of high kilovoltage (p = 0.02); this correlation was not found in the low-dose protocol (p = 0.47). Median values of SSDE and DLP were significantly (p < 0.001) lower and less dispersed in the low-dose protocol [9.22 mGy (IQR 7.84-12.1 mGy) vs. 26.5 mGy (IQR 21.3-36.3 mGy) in the standard protocol] and [97 mGy cm (IQR 78-134 mGy cm) vs. 253 mGy cm (IQR 216-404 mGy cm) in the standard protocol], respectively. The overall quality of the images obtained with the low-dose protocol was considered good or excellent in 96% of the studies. The parameters associated with image quality in a multivariable model (C statistic = 0.792) were heart rate (estimated coefficient, -0,12 [95% confidence interval: -0.2, -0.04]; p < 0.01) and the SSDE (estimated coefficient, -0,26 [95% confidence interval: -0.51, -0.01]; p < 0.05). The CAD-RADS modifier for a not fully evaluable or diagnostic study was used on two occasions (4%); the final measures for the diagnosis of coronary disease were sensitivity 100%, specificity 94%, and efficacy 94%. CONCLUSIONS In the standard protocol, the radiologist selects higher kilovoltage for CT angiography studies for patients whose previous calcium score indicates the presence of coronary calcium. In the low-dose protocol, linking kilovoltage with body mass index enables the dose of radiation to be reduced by 65% while obtaining excellent or good image quality in 96% of studies and excellent diagnostic performance.
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Affiliation(s)
- H Cuellar-Calabria
- Àrea d'Imatge Cardiovascular, Servicio de Radiodiagnóstico, Institut Diagnòstic per la Imatge (IDI), Hospital Universitari Vall d'Hebron, Barcelona, Spain; Vall d'Hebron Research Institute (VHIR), Barcelona, Spain; Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain.
| | - G Burcet
- Àrea d'Imatge Cardiovascular, Servicio de Radiodiagnóstico, Institut Diagnòstic per la Imatge (IDI), Hospital Universitari Vall d'Hebron, Barcelona, Spain; Vall d'Hebron Research Institute (VHIR), Barcelona, Spain; Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - M S Juarez-Garcia
- Àrea d'Imatge Cardiovascular, Servicio de Radiodiagnóstico, Institut Diagnòstic per la Imatge (IDI), Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | - J L Reyes-Juárez
- Àrea d'Imatge Cardiovascular, Servicio de Radiodiagnóstico, Institut Diagnòstic per la Imatge (IDI), Hospital Universitari Vall d'Hebron, Barcelona, Spain; Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
| | - M N Pizzi
- Servicio de Cardiología, Hospital Universitari Vall d'Hebron, Barcelona, Spain; Vall d'Hebron Research Institute (VHIR), Barcelona, Spain; Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - S Aguadé-Bruix
- Servicio de Medicina Nuclear, Hospital Universitari Vall d'Hebron, Barcelona, Spain; Vall d'Hebron Research Institute (VHIR), Barcelona, Spain; Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - A Roque
- Àrea d'Imatge Cardiovascular, Servicio de Radiodiagnóstico, Institut Diagnòstic per la Imatge (IDI), Hospital Universitari Vall d'Hebron, Barcelona, Spain; Vall d'Hebron Research Institute (VHIR), Barcelona, Spain; Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
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Cuellar-Calabria H, Burcet G, Juarez-Garcia M, Reyes-Juárez J, Pizzi M, Aguadé-Bruix S, Roque A. Implantación de un protocolo de angio-TC coronaria basado en el índice de masa corporal: reducción de dosis, calidad de imagen y rendimiento diagnóstico. RADIOLOGIA 2022. [DOI: 10.1016/j.rx.2022.01.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Third-Generation Dual-Source Computed Tomography for Coronary Angiography With Individually Tailored Scan Protocols Can Achieve a Low Radiation Dose With Good Image Quality in Unselected Patients. J Comput Assist Tomogr 2021; 46:41-49. [DOI: 10.1097/rct.0000000000001229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Jin L, Jie B, Gao Y, Jiang A, Weng T, Li M. Low dose contrast media in step-and-shoot coronary angiography with third-generation dual-source computed tomography: feasibility of using 30 mL of contrast media in patients with body surface area <1.7 m 2. Quant Imaging Med Surg 2021; 11:2598-2609. [PMID: 34079726 DOI: 10.21037/qims-20-500] [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] [Indexed: 11/06/2022]
Abstract
Background Reducing contrast media volume in coronary computed tomography angiography minimizes the risk of adverse events but may compromise diagnostic image quality. We aimed to evaluate coronary computed tomography angiography's diagnostic image quality while using 30 mL of contrast media in patients with a body surface area <1.7 m2. Methods This prospective study included patients who underwent coronary computed tomography angiography from May 2018 to June 2019. The patients were divided into a low-dose group, who received 30 mL of contrast media, and a routine-dose group, who received contrast media based on body weight. Patient characteristics, coronary computed tomography angiography results, and quantitative and qualitative image results were assessed and compared. Results In total, 103 patients with a body surface area <1.7 m2 were 53 in the low-dose group and 50 in the routine-dose group. Sex, age, body surface area, body weight, and heart rate were similar between the groups (P>0.05). A contrast media volume of 30±0 mL was used for the low-dose group, and 41.62±4.59 mL was used for the routine-dose group. The low-dose group's computed tomography values were significantly different from those of the routine-dose group (P<0.05). The radiologists demonstrated agreement regarding diagnostic image quality and accuracy (kappa =0.91 and 0.85, respectively). Conclusions Using 30 mL of contrast media for coronary computed tomography angiography in patients with a body surface area <1.7 m2 provided a suitable diagnostic image quality for coronary artery disease diagnosis. Although radiation doses were similar between the groups, the decreased contrast media volume was likely beneficial for the patients.
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Affiliation(s)
- Liang Jin
- Radiology Department, Huadong Hospital, affiliated with Fudan University, Shanghai, China
| | - Bing Jie
- Radiology Department, Shanghai Pulmonary Hospital, Affiliated with Tongji University, Shanghai, China
| | - Yiyi Gao
- Radiology Department, Huadong Hospital, affiliated with Fudan University, Shanghai, China
| | - An'qi Jiang
- Radiology Department, Huadong Hospital, affiliated with Fudan University, Shanghai, China
| | - Tingwen Weng
- Cardiology Department, Huadong Hospital, Affiliated with Fudan University, Shanghai, China
| | - Ming Li
- Radiology Department, Huadong Hospital, affiliated with Fudan University, Shanghai, China.,Institute of Functional and Molecular Medical Imaging, Fudan University, Shanghai, China
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Takao S, Nishie A, Asayama Y, Ishigami K, Ushijima Y, Kakihara D, Nakayama T, Fujita N, Morita K, Ishimatsu K, Yoshizumi T, Ikegami T, Kondo M, Honda H. Improved visualization of a fine intrahepatic biliary duct on drip infusion cholangiography-computed tomography: Impact of knowledge-based iterative model reconstruction. Hepatol Res 2020; 50:629-634. [PMID: 31863713 DOI: 10.1111/hepr.13477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 12/07/2019] [Accepted: 12/17/2019] [Indexed: 02/08/2023]
Abstract
AIM The purpose of this study was to investigate the visualization of fine biliary ducts with knowledge-based iterative model reconstruction (IMR) in low-dose drip infusion computed tomography (CT) cholangiography (DIC-CT) as compared with filtered back projection (FBP) and hybrid iterative reconstruction (iDose4 ). METHODS A total of 38 patients underwent DIC-CT for living donor liver transplantation. CT was performed approximately 20 min after the end of the infusion of meglumine iotroxate (100 mL). Images were reconstructed using FBP, iDose4 , and IMR, and 1-mm slice images at fixed window level and width were prepared for assessment. Two reviewers independently evaluated the quality of visualization of the fine biliary ducts of the caudate lobe (B1) using a 5-point scale. The visualization scores of three reconstructed images were compared using the Kruskal-Wallis test and Mann-Whitney U-test. RESULTS For reviewer 1, the visualization score of IMR was significantly higher than that of FBP (P = 0.012), and tended to be higher than that of iDose4 (P = 0.078). For reviewer 2, the visualization score of IMR was significantly higher than those of both FBP and iDose4 (P < 0.01). CONCLUSIONS IMR showed better visualization of B1 on DIC-CT than FBP or iDose4 . DIC-CT reconstructed with IMR may be useful to the anatomical grasp of biliary tracts in cases of hepatectomy.
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Affiliation(s)
- Seiichiro Takao
- Departments of Clinical Radiology, Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Akihiro Nishie
- Departments of Clinical Radiology, Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yoshiki Asayama
- Departments of Clinical Radiology, Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kousei Ishigami
- Departments of Clinical Radiology, Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yasuhiro Ushijima
- Departments of Clinical Radiology, Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Daisuke Kakihara
- Departments of Clinical Radiology, Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tomohiro Nakayama
- Departments of Clinical Radiology, Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Nobuhiro Fujita
- Departments of Clinical Radiology, Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Koichiro Morita
- Departments of Clinical Radiology, Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Keisuke Ishimatsu
- Departments of Clinical Radiology, Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tomoharu Yoshizumi
- Departments of Clinical Radiology, Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Toru Ikegami
- Departments of Clinical Radiology, Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masatoshi Kondo
- Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan
| | - Hiroshi Honda
- Departments of Clinical Radiology, Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Noël PB, Engels S, Köhler T, Muenzel D, Franz D, Rasper M, Rummeny EJ, Dobritz M, Fingerle AA. Evaluation of an iterative model-based CT reconstruction algorithm by intra-patient comparison of standard and ultra-low-dose examinations. Acta Radiol 2018; 59:1225-1231. [PMID: 29320863 DOI: 10.1177/0284185117752551] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background The explosive growth of computer tomography (CT) has led to a growing public health concern about patient and population radiation dose. A recently introduced technique for dose reduction, which can be combined with tube-current modulation, over-beam reduction, and organ-specific dose reduction, is iterative reconstruction (IR). Purpose To evaluate the quality, at different radiation dose levels, of three reconstruction algorithms for diagnostics of patients with proven liver metastases under tumor follow-up. Material and Methods A total of 40 thorax-abdomen-pelvis CT examinations acquired from 20 patients in a tumor follow-up were included. All patients were imaged using the standard-dose and a specific low-dose CT protocol. Reconstructed slices were generated by using three different reconstruction algorithms: a classical filtered back projection (FBP); a first-generation iterative noise-reduction algorithm (iDose4); and a next generation model-based IR algorithm (IMR). Results The overall detection of liver lesions tended to be higher with the IMR algorithm than with FBP or iDose4. The IMR dataset at standard dose yielded the highest overall detectability, while the low-dose FBP dataset showed the lowest detectability. For the low-dose protocols, a significantly improved detectability of the liver lesion can be reported compared to FBP or iDose4 ( P = 0.01). The radiation dose decreased by an approximate factor of 5 between the standard-dose and the low-dose protocol. Conclusion The latest generation of IR algorithms significantly improved the diagnostic image quality and provided virtually noise-free images for ultra-low-dose CT imaging.
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Affiliation(s)
- Peter B Noël
- Department of Diagnostic and Interventional Radiology, Technische Universität München, Munich, Germany
- Physics Department & Munich School of BioEngineering, Technische Universität München, Garching, Germany
| | - Stephan Engels
- Department of Diagnostic and Interventional Radiology, Technische Universität München, Munich, Germany
| | | | - Daniela Muenzel
- Department of Diagnostic and Interventional Radiology, Technische Universität München, Munich, Germany
- Physics Department & Munich School of BioEngineering, Technische Universität München, Garching, Germany
| | - Daniela Franz
- Department of Diagnostic and Interventional Radiology, Technische Universität München, Munich, Germany
| | - Michael Rasper
- Department of Diagnostic and Interventional Radiology, Technische Universität München, Munich, Germany
| | - Ernst J Rummeny
- Department of Diagnostic and Interventional Radiology, Technische Universität München, Munich, Germany
| | - Martin Dobritz
- Department of Diagnostic and Interventional Radiology, Technische Universität München, Munich, Germany
| | - Alexander A Fingerle
- Department of Diagnostic and Interventional Radiology, Technische Universität München, Munich, Germany
- Physics Department & Munich School of BioEngineering, Technische Universität München, Garching, Germany
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Nazli SB, Aghamiri SMR, Gholizadeh Sendani N, Shams Akhtari A. EVALUATION OF RADIATION ABSORBED DOSE AND IMAGE QUALITY IN DIFFERENT RETROSPECTIVE-ECG GATING ACQUISITION METHODS OF CARDIAC CT ANGIOGRAPHY. RADIATION PROTECTION DOSIMETRY 2018; 178:304-309. [PMID: 28981808 DOI: 10.1093/rpd/ncx111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/28/2017] [Indexed: 06/07/2023]
Abstract
Cardiac computed tomography angiography (CCTA) studies have risen concern of radiobiological effects over the patients. Therefore, estimating radiation doses absorbed during CCTA is important. In this study, we compared radiation dose and image quality by using three different retrospective electrocardiography (ECG) protocols. A total of 123 patients undergoing CCTA were divided in three different groups. We used full-dose modulation (CareDose4D) technique in group (1); fixed tube current 200 mAs for group (2); and in group (3), chest circumference was used to adapt tube current (180-200 mAs) and tube potential (100-120 kVp). For groups (1) and (2), tube potential adapted depends on body mass index (BMI) in which it was 100 kVp for BMI < 27 kg/m2, and 120 kVp for BMI ≥ 27 kg/m2. Quantitive assessment of image quality was calculated by measuring signal intensity (SI) and image noise (IN) in the proximal segments of aorta root on left and right coronary arteries. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were also calculated by using SI and IN. Two experienced radiologists using a 4-point scale assessed the subjective image quality. Our results show that in group (1), the mean effective dose was 4.46 mSv (range: 1.75-8.6 mSv) and for group (2), the mean effective radiation dose was 5.07 mSv (range: 2.57-9.74 mSv) and in group (3), the mean effective dose was 5.85 mSv (range: 3.36-12.17 mSv). Group (1) representing 12% and 23% decrease in radiation dose comparing by groups (2) and (3). In multivariate analysis, adjusting for BMI, radiation dose for patients with BMI < 27 kg/m2 was significantly different; 2.53 mSv for group (1) compared to 3.54 mSv in group (2) and 5.207 in group (3) (p < 0.0001). In addition, lowering tube potential from 120 to 100 kVp in 200 mAs fixed tube current, represents 27% decrease in radiation dose. The quantitative image quality (IN, SI, SNR and CNR) was not statistically significant among the groups. To sum up, Retrospective-ECG gating may reduce radiation dose by using automatic tube current modulation and 100kVp tube potential with preservation of image quality in patient's whose BMI < 27 kg/m2.
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Affiliation(s)
| | | | | | - Amin Shams Akhtari
- Department of Emergency Medicine, Faculty of Medical Science, Shahid Beheshti Medical University, Tehran, Iran
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Ehn S, Sellerer T, Muenzel D, Fingerle AA, Kopp F, Duda M, Mei K, Renger B, Herzen J, Dangelmaier J, Schwaiger BJ, Sauter A, Riederer I, Renz M, Braren R, Rummeny EJ, Pfeiffer F, Noël PB. Assessment of quantification accuracy and image quality of a full-body dual-layer spectral CT system. J Appl Clin Med Phys 2018; 19:204-217. [PMID: 29266724 PMCID: PMC5768037 DOI: 10.1002/acm2.12243] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 10/24/2017] [Accepted: 11/02/2017] [Indexed: 11/20/2022] Open
Abstract
The performance of a recently introduced spectral computed tomography system based on a dual-layer detector has been investigated. A semi-anthropomorphic abdomen phantom for CT performance evaluation was imaged on the dual-layer spectral CT at different radiation exposure levels (CTDIvol of 10 mGy, 20 mGy and 30 mGy). The phantom was equipped with specific low-contrast and tissue-equivalent inserts including water-, adipose-, muscle-, liver-, bone-like materials and a variation in iodine concentrations. Additionally, the phantom size was varied using different extension rings to simulate different patient sizes. Contrast-to-noise (CNR) ratio over the range of available virtual mono-energetic images (VMI) and the quantitative accuracy of VMI Hounsfield Units (HU), effective-Z maps and iodine concentrations have been evaluated. Central and peripheral locations in the field-of-view have been examined. For all evaluated imaging tasks the results are within the calculated theoretical range of the tissue-equivalent inserts. Especially at low energies, the CNR in VMIs could be boosted by up to 330% with respect to conventional images using iDose/spectral reconstructions at level 0. The mean bias found in effective-Z maps and iodine concentrations averaged over all exposure levels and phantom sizes was 1.9% (eff. Z) and 3.4% (iodine). Only small variations were observed with increasing phantom size (+3%) while the bias was nearly independent of the exposure level (±0.2%). Therefore, dual-layer detector based CT offers high quantitative accuracy of spectral images over the complete field-of-view without any compromise in radiation dose or diagnostic image quality.
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Affiliation(s)
- Sebastian Ehn
- Chair of Biomedical PhysicsDepartment of Physics and Munich School of BioEngineeringTechnical University of MunichGarchingGermany
| | - Thorsten Sellerer
- Chair of Biomedical PhysicsDepartment of Physics and Munich School of BioEngineeringTechnical University of MunichGarchingGermany
| | - Daniela Muenzel
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Alexander A. Fingerle
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Felix Kopp
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Manuela Duda
- Chair of Biomedical PhysicsDepartment of Physics and Munich School of BioEngineeringTechnical University of MunichGarchingGermany
| | - Kai Mei
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Bernhard Renger
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Julia Herzen
- Chair of Biomedical PhysicsDepartment of Physics and Munich School of BioEngineeringTechnical University of MunichGarchingGermany
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Julia Dangelmaier
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Benedikt J. Schwaiger
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Andreas Sauter
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Isabelle Riederer
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Martin Renz
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Rickmer Braren
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Ernst J. Rummeny
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Franz Pfeiffer
- Chair of Biomedical PhysicsDepartment of Physics and Munich School of BioEngineeringTechnical University of MunichGarchingGermany
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
| | - Peter B. Noël
- Chair of Biomedical PhysicsDepartment of Physics and Munich School of BioEngineeringTechnical University of MunichGarchingGermany
- Department of diagnostic and interventional RadiologyTechnical University of MunichMunichGermany
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Liew G, Chow C, van Pelt N, Younger J, Jelinek M, Chan J, Hamilton-Craig C. Cardiac Society of Australia and New Zealand Position Statement: Coronary Artery Calcium Scoring. Heart Lung Circ 2017; 26:1239-1251. [DOI: 10.1016/j.hlc.2017.05.130] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 05/06/2017] [Indexed: 01/07/2023]
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Ippolito D, Casiraghi AS, Franzesi CT, Fior D, Meloni F, Sironi S. Low-dose computed tomography with 4 th-generation iterative reconstruction algorithm in assessment of oncologic patients. World J Gastrointest Oncol 2017; 9:423-430. [PMID: 29085569 PMCID: PMC5648986 DOI: 10.4251/wjgo.v9.i10.423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 07/25/2017] [Accepted: 08/16/2017] [Indexed: 02/05/2023] Open
Abstract
AIM To compare radiation dose and image quality of low-dose computed tomography (CT) protocol combined with hybrid-iterative reconstruction algorithm with standard-dose CT examinations for follow-up of oncologic patients. METHODS Fifty-one patients with known malignant diseases which underwent, during clinical follow-up, both standard-dose and low-dose whole-body CT scans were enrolled. Low-dose CT was performed on 256-row scanner, with 120 kV and automated mA modulation, and iterative reconstruction algorithm. Standard-dose CT was performed on 16-rows scanner, with 120 kV, 200-400 mAs (depending on patient weight). We evaluated density values and signal-to-noise ratio, along with image noise (SD), sharpness and diagnostic quality with 4-point scale. RESULTS Density values in liver, spleen and aorta were higher in low-dose images (liver 112.55 HU vs 103.90 HU, P < 0.001), as SD values in liver and spleen (liver 16.81 vs 14.41). Volumetric-Computed-Tomographic-Dose-Index (CTDIvol) and Dose-Length-Product (DLP) were significantly lower in low-dose CT as compared to standard-dose (DLP 1025.6 mGy*cm vs 1429.2 mGy*cm, P < 0.001) with overall dose reduction of 28.9%. Qualitative analysis did not reveal significant differences in image noise and diagnostic quality. CONCLUSION Automatic tube-current modulation combined with hybrid-iterative algorithm allows radiation dose reduction of 28.9% without loss of diagnostic quality, being useful in reducing dose exposure in oncologic patients.
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Affiliation(s)
- Davide Ippolito
- Department of Diagnostic Radiology, “San Gerardo” Hospital, 20900 Monza, Italy
- School of Medicine, University of Milano-Bicocca, 20900 Monza, Italy
| | - Alessandra Silvia Casiraghi
- Department of Diagnostic Radiology, “San Gerardo” Hospital, 20900 Monza, Italy
- School of Medicine, University of Milano-Bicocca, 20900 Monza, Italy
| | - Cammillo Talei Franzesi
- Department of Diagnostic Radiology, “San Gerardo” Hospital, 20900 Monza, Italy
- School of Medicine, University of Milano-Bicocca, 20900 Monza, Italy
| | - Davide Fior
- Department of Diagnostic Radiology, “San Gerardo” Hospital, 20900 Monza, Italy
- School of Medicine, University of Milano-Bicocca, 20900 Monza, Italy
| | - Franca Meloni
- School of Medicine, University of Milano-Bicocca, 20900 Monza, Italy
| | - Sandro Sironi
- School of Medicine, University of Milano-Bicocca, 20900 Monza, Italy
- Department of Diagnostic Radiology, “Papa Giovanni XXIII” Hospital, 24127 Bergamo, Italy
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Image quality and contrast agent exposure in cardiac computed tomography angiography prior to transcatheter aortic valve implantation procedures using different acquisition protocols. Eur J Radiol Open 2017; 4:75-83. [PMID: 28702479 PMCID: PMC5491755 DOI: 10.1016/j.ejro.2017.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 06/04/2017] [Accepted: 06/18/2017] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND ECG-gated cardiac computed tomography angiography (CCTA) has found widespread use for prosthesis sizing before transcatheter aortic valve implantation (TAVI). However, still little data exists on the optimal scan-strategy in such patients. We hypothesized that prospectively triggered CCTA can enable the visualization of aortic valve structures and peripheral arteries with lower radiation and contrast agent exposure in patients considered for TAVI compared to retrospectively gated protocols. METHODS All studies were performed using a 256 multi-detector single source CT (iCT Philips, Best, Netherlands). With the prospective protocol the whole volume from the heart to the iliofemoral arteries scanned using prospective triggering. With the retrospective protocol a first retrospectively gated scan was performed for the heart and the iliofemoral part was subsequently scanned using a second non-triggered scan. Image quality was assessed semi-quantitatively and signal-to-noise- (SNR) and contrast-to-noise-ratios (CNR) were obtained for all scans. RESULTS Prospective CCTA was performed in 74 and in 34 patients, respectively using non-tailored and BMI adapted scans, whereas retrospective CCTA was performed in 57 patients. Prospective scans required lower contrast agent administration compared to retrospective scans (71 ± 8 mL versus 91 ± 15 mL, p < 0.01) and resulted in lower radiation exposure (26 ± 7mSv for retrospective versus 15 ± 3mSv for non-tailored prospective versus 8 ± 4mSv for BMI-adapted prospective scans, p < 0.01). Visual image quality was better for the evaluation of aortic valve structures and similar for the assessment of iliofemoral anatomy with prospective versus retrospective scans. In addition, contrast density, SNR and CNR were higher in the ascending aorta with prospective versus retrospective CCTA (434 ± 98HU versus 349 ± 112HU; 35 ± 14 versus 24 ± 9 and 31 ± 11 versus 16 ± 7, p < 0.001 for all). Subsection analysis by heart rate groups demonstrated that both image quality and CNR were significantly higher in patients with prospective versus retrospective CCTA, irrespective of the heart rate during image acquisition. CONCLUSION Prospectively triggered CCTA allows for improved visualization of aortic valve structures and peripheral arteries in patients scheduled for TAVI with simultaneously reduced contrast agent dose and radiation exposure. Therefore, this acquisition mode seems to be the preferred for the evaluation of patients considered for TAVI.
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André F, Fortner P, Vembar M, Mueller D, Stiller W, Buss SJ, Kauczor HU, Katus HA, Korosoglou G. Improved image quality with simultaneously reduced radiation exposure: Knowledge-based iterative model reconstruction algorithms for coronary CT angiography in a clinical setting. J Cardiovasc Comput Tomogr 2017; 11:213-220. [DOI: 10.1016/j.jcct.2017.02.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Revised: 02/16/2017] [Accepted: 02/19/2017] [Indexed: 12/01/2022]
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Kok M, de Haan MW, Mihl C, Eijsvoogel NG, Hendriks BM, Sailer AM, Derks K, Schnerr RS, Schurink GWH, Wildberger JE, Das M. Individualized CT Angiography Protocols for the Evaluation of the Aorta: A Feasibility Study. J Vasc Interv Radiol 2016; 27:531-8. [DOI: 10.1016/j.jvir.2016.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 01/02/2016] [Accepted: 01/02/2016] [Indexed: 01/16/2023] Open
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Individualized reduction of radiation dose with a chest circumference-adapted technique and iterative reconstructions in 256-slice retrospective and prospective ECG-triggered computed tomography coronary angiography. Coron Artery Dis 2016; 26:308-16. [PMID: 25714067 DOI: 10.1097/mca.0000000000000232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To assess the impact of chest circumference (CC)-adjusted tube current and iterative reconstructions (iDose) on individualized radiation dose reduction and image quality (IQ) in ECG-triggered computed tomography coronary angiography (CTCA). MATERIALS AND METHODS A total of 102 patients underwent retrospectively ECG-triggered CTCA utilizing CC-adapted tube current [mAs=1000×(0.051×CC-23.765)/900] and filtered back projection (FBP) reconstruction (group A). On the basis of the CC-adjusted tube current technique, 54 patients (group B) underwent retrospective ECG-triggered CTCA with a 20% mAs reduction compared with group A and 90 patients (group C) underwent prospective ECG-triggered CTCA with an 80% mAs reduction compared with group A; both groups B and C were reconstructed with FBP and iDose. Subjective IQ was assessed, and image noise, signal-to-noise, and contrast-to-noise ratios (SNR and CNR) were quantified. RESULTS Patients in group A had the highest radiation dose, followed by group B and group C. iDose provided decreased image noise and increased SNR and CNR, as did subjective IQ. The image noise was higher and SNR and CNR in group B were obviously lower than those in group A with FBP, but in group B, iDose4 increased the mean objective IQ. There was no difference between group B with iDose and group A with FBP, as was the case with subjective IQ. CONCLUSION The combination of a CC-adapted technique, prospective triggering, and partial iterative reconstruction techniques reduces the radiation dose significantly, without significant degradation of IQ.
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van Dijk JD, Huizing ED, Jager PL, Ottervanger JP, Knollema S, Slump CH, van Dalen JA. A practical approach for a patient-tailored dose protocol in coronary CT angiography using prospective ECG triggering. Int J Cardiovasc Imaging 2016; 32:531-8. [PMID: 26563107 PMCID: PMC4751172 DOI: 10.1007/s10554-015-0802-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 11/02/2015] [Indexed: 11/27/2022]
Abstract
To derive and validate a practical patient-specific dose protocol to obtain an image quality, expressed by the image noise, independent of patients' size and a better radiation dose justification in coronary CT angiography (CCTA) using prospective ECG triggering. 43 patients underwent clinically indicated CCTA. The image noise, defined as the standard deviation of pixel attenuation values in a homogeneous region in the liver, was determined in all scans. Subsequently, this noise was normalized to the radiation exposure. Next, three patient-specific parameters, body weight, body mass index and mass per length (MPL), were tested for the best correlation with normalized image noise. From these data, a new dose protocol to provide a less variable image noise was derived and subsequently validated in 84 new patients. The normalized image noise increased for heavier patients for all patients' specific parameters (p < 0.001). MPL correlated best with the normalized image noise and was selected for dose protocol optimization. This new protocol resulted in image noise levels independent of patients' MPL (p = 0.28). A practical method to obtain CCTA images with noise levels independent of patients' MPL was derived and validated. It results in a less variable image quality and better radiation exposure justification and can also be used for CT scanners from other vendors.
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Affiliation(s)
- J D van Dijk
- Department of Nuclear Medicine, Isala Hospital, PO Box 10400, 8000 GK, Zwolle, The Netherlands.
- MIRA: Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands.
| | - E D Huizing
- Department of Nuclear Medicine, Isala Hospital, PO Box 10400, 8000 GK, Zwolle, The Netherlands.
- MIRA: Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands.
| | - P L Jager
- Department of Nuclear Medicine, Isala Hospital, PO Box 10400, 8000 GK, Zwolle, The Netherlands.
| | - J P Ottervanger
- Department of Cardiology, Isala Hospital, Zwolle, The Netherlands.
| | - S Knollema
- Department of Nuclear Medicine, Isala Hospital, PO Box 10400, 8000 GK, Zwolle, The Netherlands.
| | - C H Slump
- MIRA: Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands.
| | - J A van Dalen
- Department of Medical Physics, Isala Hospital, Zwolle, The Netherlands.
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Geyer LL, Schoepf UJ, Meinel FG, Nance JW, Bastarrika G, Leipsic JA, Paul NS, Rengo M, Laghi A, De Cecco CN. State of the Art: Iterative CT Reconstruction Techniques. Radiology 2015. [PMID: 26203706 DOI: 10.1148/radiol.2015132766] [Citation(s) in RCA: 439] [Impact Index Per Article: 43.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Lucas L Geyer
- From the Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, MSC 226, 25 Courtenay Dr, Charleston, SC 29425 (L.L.G., U.J.S., F.G.M., J.W.N., C.N.D.); Department of Radiology, Sunnybrook Health Sciences Centre, Toronto, Ont, Canada (G.B.); Department of Radiology, University of British Columbia, Vancouver, BC, Canada (J.A.L.); Department of Radiology, Toronto General Hospital, University of Toronto, Toronto, Ont, Canada (N.S.P.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome Sapienza-Polo Pontino, Latina, Italy (M.R., A.L., C.N.D.)
| | - U Joseph Schoepf
- From the Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, MSC 226, 25 Courtenay Dr, Charleston, SC 29425 (L.L.G., U.J.S., F.G.M., J.W.N., C.N.D.); Department of Radiology, Sunnybrook Health Sciences Centre, Toronto, Ont, Canada (G.B.); Department of Radiology, University of British Columbia, Vancouver, BC, Canada (J.A.L.); Department of Radiology, Toronto General Hospital, University of Toronto, Toronto, Ont, Canada (N.S.P.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome Sapienza-Polo Pontino, Latina, Italy (M.R., A.L., C.N.D.)
| | - Felix G Meinel
- From the Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, MSC 226, 25 Courtenay Dr, Charleston, SC 29425 (L.L.G., U.J.S., F.G.M., J.W.N., C.N.D.); Department of Radiology, Sunnybrook Health Sciences Centre, Toronto, Ont, Canada (G.B.); Department of Radiology, University of British Columbia, Vancouver, BC, Canada (J.A.L.); Department of Radiology, Toronto General Hospital, University of Toronto, Toronto, Ont, Canada (N.S.P.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome Sapienza-Polo Pontino, Latina, Italy (M.R., A.L., C.N.D.)
| | - John W Nance
- From the Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, MSC 226, 25 Courtenay Dr, Charleston, SC 29425 (L.L.G., U.J.S., F.G.M., J.W.N., C.N.D.); Department of Radiology, Sunnybrook Health Sciences Centre, Toronto, Ont, Canada (G.B.); Department of Radiology, University of British Columbia, Vancouver, BC, Canada (J.A.L.); Department of Radiology, Toronto General Hospital, University of Toronto, Toronto, Ont, Canada (N.S.P.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome Sapienza-Polo Pontino, Latina, Italy (M.R., A.L., C.N.D.)
| | - Gorka Bastarrika
- From the Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, MSC 226, 25 Courtenay Dr, Charleston, SC 29425 (L.L.G., U.J.S., F.G.M., J.W.N., C.N.D.); Department of Radiology, Sunnybrook Health Sciences Centre, Toronto, Ont, Canada (G.B.); Department of Radiology, University of British Columbia, Vancouver, BC, Canada (J.A.L.); Department of Radiology, Toronto General Hospital, University of Toronto, Toronto, Ont, Canada (N.S.P.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome Sapienza-Polo Pontino, Latina, Italy (M.R., A.L., C.N.D.)
| | - Jonathon A Leipsic
- From the Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, MSC 226, 25 Courtenay Dr, Charleston, SC 29425 (L.L.G., U.J.S., F.G.M., J.W.N., C.N.D.); Department of Radiology, Sunnybrook Health Sciences Centre, Toronto, Ont, Canada (G.B.); Department of Radiology, University of British Columbia, Vancouver, BC, Canada (J.A.L.); Department of Radiology, Toronto General Hospital, University of Toronto, Toronto, Ont, Canada (N.S.P.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome Sapienza-Polo Pontino, Latina, Italy (M.R., A.L., C.N.D.)
| | - Narinder S Paul
- From the Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, MSC 226, 25 Courtenay Dr, Charleston, SC 29425 (L.L.G., U.J.S., F.G.M., J.W.N., C.N.D.); Department of Radiology, Sunnybrook Health Sciences Centre, Toronto, Ont, Canada (G.B.); Department of Radiology, University of British Columbia, Vancouver, BC, Canada (J.A.L.); Department of Radiology, Toronto General Hospital, University of Toronto, Toronto, Ont, Canada (N.S.P.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome Sapienza-Polo Pontino, Latina, Italy (M.R., A.L., C.N.D.)
| | - Marco Rengo
- From the Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, MSC 226, 25 Courtenay Dr, Charleston, SC 29425 (L.L.G., U.J.S., F.G.M., J.W.N., C.N.D.); Department of Radiology, Sunnybrook Health Sciences Centre, Toronto, Ont, Canada (G.B.); Department of Radiology, University of British Columbia, Vancouver, BC, Canada (J.A.L.); Department of Radiology, Toronto General Hospital, University of Toronto, Toronto, Ont, Canada (N.S.P.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome Sapienza-Polo Pontino, Latina, Italy (M.R., A.L., C.N.D.)
| | - Andrea Laghi
- From the Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, MSC 226, 25 Courtenay Dr, Charleston, SC 29425 (L.L.G., U.J.S., F.G.M., J.W.N., C.N.D.); Department of Radiology, Sunnybrook Health Sciences Centre, Toronto, Ont, Canada (G.B.); Department of Radiology, University of British Columbia, Vancouver, BC, Canada (J.A.L.); Department of Radiology, Toronto General Hospital, University of Toronto, Toronto, Ont, Canada (N.S.P.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome Sapienza-Polo Pontino, Latina, Italy (M.R., A.L., C.N.D.)
| | - Carlo N De Cecco
- From the Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, MSC 226, 25 Courtenay Dr, Charleston, SC 29425 (L.L.G., U.J.S., F.G.M., J.W.N., C.N.D.); Department of Radiology, Sunnybrook Health Sciences Centre, Toronto, Ont, Canada (G.B.); Department of Radiology, University of British Columbia, Vancouver, BC, Canada (J.A.L.); Department of Radiology, Toronto General Hospital, University of Toronto, Toronto, Ont, Canada (N.S.P.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome Sapienza-Polo Pontino, Latina, Italy (M.R., A.L., C.N.D.)
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Litmanovich DE, Tack DM, Shahrzad M, Bankier AA. Dose reduction in cardiothoracic CT: review of currently available methods. Radiographics 2015; 34:1469-89. [PMID: 25310412 DOI: 10.1148/rg.346140084] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Radiation exposure from computed tomography (CT) has received much attention lately in the medical literature and the media, given the relatively high radiation dose that characterizes a CT examination. Although there are a variety of possible strategies for reducing radiation exposure from CT in an individual patient, optimal CT image acquisition requires that the radiologist understand new scanner technology and how to implement the most effective means of dose reduction while maintaining image quality. The authors describe a practical approach to dose reduction in cardiothoracic radiology, discussing CT radiation dose metrics (eg, CT dose index, dose-length product, effective diameter, and size-specific dose estimate) as well as CT scanner parameters that directly or indirectly influence radiation dose (eg, scan length, x-ray tube output, tube current modulation, pitch, image reconstruction techniques [including iterative reconstruction], and noise reduction). These variables are discussed in terms of their relative importance to image quality and the implications of parametric changes for image quality and diagnostic content, and practical recommendations are made for their immediate implementation in the clinical setting. Taken together, the principles of physics and key parameters involved in reducing radiation dose while maintaining image quality can serve as a "survival guide" for a diagnostic radiology practice.
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Affiliation(s)
- Diana E Litmanovich
- From the Department of Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Ave, Shapiro 4, Boston, MA 02215 (D.E.L., M.S., A.A.B.); and Department of Radiology, Epicura Hospital, Baudour, Belgium (D.M.T.)
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Jia Y, Xie D, Zhu K, Xiao X. Clinical application of 100 kVp acquisition with an iterative reconstruction technique in retrospective electrocardiogram-gated thoracoabdominal aortic CT angiography. Clin Radiol 2015; 70:588-94. [DOI: 10.1016/j.crad.2015.01.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 01/04/2015] [Accepted: 01/16/2015] [Indexed: 11/27/2022]
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Lu C, Wang Z, Ji J, Wang H, Hu X, Chen C. Evaluation of a chest circumference-adapted protocol for low-dose 128-slice coronary CT angiography with prospective electrocardiogram triggering. Korean J Radiol 2015; 16:13-20. [PMID: 25598671 PMCID: PMC4296260 DOI: 10.3348/kjr.2015.16.1.13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 11/10/2014] [Indexed: 01/16/2023] Open
Abstract
Objective To assess the effect of chest circumference-adapted scanning protocol on radiation exposure and image quality in patients undergoing prospective electrocardiogram (ECG)-triggered coronary CT angiography (CCTA). Materials and Methods One hundred-eighty-five consecutive patients, who had undergone prospective ECG triggering CCTA with a 128-slice CT, were included in the present study. Nipple-level chest circumference, body weight and height were measured before CT examinations. Patients were divided into four groups based on kV/ref·mAs = 100/200, 100/250, 120/200, and 120/250, when patient's chest circumference was ≤ 85.0 (n = 56), 85.0-90.0 (n = 53), 90.0-95.0 (n = 44), and > 95.0 (n = 32), respectively. Image quality per-segment was independently assessed by two experienced observers. Image noise and attenuation were also measured. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The effective radiation dose was calculated using CT dose volume index and the dose-length product. Results A significant correlation was observed between patients' chest circumference and body mass index (r = 0.762, p < 0.001). Chest circumference ranged from 74 to 105 cm, and the mean effective radiation dose was 1.9-3.8 mSv. Diagnostic image quality was obtained in 98.5% (2440/2478) of all evaluated coronary segments without any significant differences among the four groups (p = 0.650). No significant difference in image noise was observed among the four groups (p = 0.439), thus supporting the validity of the chest circumference-adapted scanning protocol. However, vessel attenuation, SNR and CNR were significantly higher in the 100 kV groups than in the 120 kV groups (p < 0.05). Conclusion A measure of chest circumference can be used to adapt tube voltage and current for individualized radiation dose control, with resultant similar image noise and sustained diagnostic image quality.
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Affiliation(s)
- Chenying Lu
- Department of Radiology, Lishui Central Hospital, The Fifth Affiliated Hospital of Wenzhou Medical College, Lishui, Zhejiang 323000, China
| | - Zufei Wang
- Department of Radiology, Lishui Central Hospital, The Fifth Affiliated Hospital of Wenzhou Medical College, Lishui, Zhejiang 323000, China
| | - Jiansong Ji
- Department of Radiology, Lishui Central Hospital, The Fifth Affiliated Hospital of Wenzhou Medical College, Lishui, Zhejiang 323000, China
| | - Hailin Wang
- Department of Radiology, Lishui Central Hospital, The Fifth Affiliated Hospital of Wenzhou Medical College, Lishui, Zhejiang 323000, China
| | - Xianghua Hu
- Department of Radiology, Lishui Central Hospital, The Fifth Affiliated Hospital of Wenzhou Medical College, Lishui, Zhejiang 323000, China
| | - Chunmiao Chen
- Department of Radiology, Lishui Central Hospital, The Fifth Affiliated Hospital of Wenzhou Medical College, Lishui, Zhejiang 323000, China
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Liao YL, Chen YS, Lai NK, Chuang KS, Tsai HY. Overbeaming and overlapping of volume-scan CT with tube current modulation in a 320-detector row CT scanner. Radiat Phys Chem Oxf Engl 1993 2014. [DOI: 10.1016/j.radphyschem.2013.12.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Introduction of an Effective Method for the Optimization of CT Protocols Using Iterative Reconstruction Algorithms: Comparison With Patient Data. AJR Am J Roentgenol 2014; 203:W434-9. [DOI: 10.2214/ajr.13.11973] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Korosoglou G, Giusca S, Gitsioudis G, Erbel C, Katus HA. Cardiac magnetic resonance and computed tomography angiography for clinical imaging of stable coronary artery disease. Diagnostic classification and risk stratification. Front Physiol 2014; 5:291. [PMID: 25147526 PMCID: PMC4123729 DOI: 10.3389/fphys.2014.00291] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 07/18/2014] [Indexed: 12/18/2022] Open
Abstract
Despite advances in the pharmacologic and interventional treatment of coronary artery disease (CAD), atherosclerosis remains the leading cause of death in Western societies. X-ray coronary angiography has been the modality of choice for diagnosing the presence and extent of CAD. However, this technique is invasive and provides limited information on the composition of atherosclerotic plaque. Coronary computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR) have emerged as promising non-invasive techniques for the clinical imaging of CAD. Hereby, CCTA allows for visualization of coronary calcification, lumen narrowing and atherosclerotic plaque composition. In this regard, data from the CONFIRM Registry recently demonstrated that both atherosclerotic plaque burden and lumen narrowing exhibit incremental value for the prediction of future cardiac events. However, due to technical limitations with CCTA, resulting in false positive or negative results in the presence of severe calcification or motion artifacts, this technique cannot entirely replace invasive angiography at the present time. CMR on the other hand, provides accurate assessment of the myocardial function due to its high spatial and temporal resolution and intrinsic blood-to-tissue contrast. Hereby, regional wall motion and perfusion abnormalities, during dobutamine or vasodilator stress, precede the development of ST-segment depression and anginal symptoms enabling the detection of functionally significant CAD. While CT generally offers better spatial resolution, the versatility of CMR can provide information on myocardial function, perfusion, and viability, all without ionizing radiation for the patients. Technical developments with these 2 non-invasive imaging tools and their current implementation in the clinical imaging of CAD will be presented and discussed herein.
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Gitsioudis G, Katus HA, Korosoglou G. Assessment of coronary artery disease using coronary computed tomography angiography and biochemical markers. World J Cardiol 2014; 6:663-670. [PMID: 25068026 PMCID: PMC4110614 DOI: 10.4330/wjc.v6.i7.663] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/16/2014] [Accepted: 05/29/2014] [Indexed: 02/06/2023] Open
Abstract
Chronic inflammatory mechanisms in the arterial wall lead to atherosclerosis, and include endothelial cell damage, inflammation, apoptosis, lipoprotein deposition, calcification and fibrosis. Cardiac computed tomography angiography (CCTA) has been shown to be a promising tool for non-invasive assessment of theses specific compositional and structural changes in coronary arteries. This review focuses on the technical background of CCTA-based quantitative plaque characterization. Furthermore, we discuss the available evidence for CCTA-based plaque characterization and the potential role of CCTA for risk stratification of patients with coronary artery disease.
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Iterative Reconstruction in 256-MDCT of Coronary Artery Bypass Grafts: Assessment of Radiation Dose Reduction and Image Quality. AJR Am J Roentgenol 2014; 202:W599. [DOI: 10.2214/ajr.13.11866] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Hofmann C, Sawall S, Knaup M, Kachelrieß M. Alpha image reconstruction (AIR): A new iterative CT image reconstruction approach using voxel-wise alpha blending. Med Phys 2014; 41:061914. [DOI: 10.1118/1.4875975] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Analysis of myocardial perfusion from vasodilator stress computed tomography: Does improvement in image quality by iterative reconstruction lead to improved diagnostic accuracy? J Cardiovasc Comput Tomogr 2014; 8:238-45. [DOI: 10.1016/j.jcct.2014.04.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 03/18/2014] [Accepted: 04/22/2014] [Indexed: 11/19/2022]
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Gitsioudis G, Hosch W, Iwan J, Voss A, Atsiatorme E, Hofmann NP, Buss SJ, Siebert S, Kauczor HU, Giannitsis E, Katus HA, Korosoglou G. When do we really need coronary calcium scoring prior to contrast-enhanced coronary computed tomography angiography? Analysis by age, gender and coronary risk factors. PLoS One 2014; 9:e92396. [PMID: 24714677 PMCID: PMC3979653 DOI: 10.1371/journal.pone.0092396] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 02/21/2014] [Indexed: 12/17/2022] Open
Abstract
Aims To investigate the value of coronary calcium scoring (CCS) as a filter scan prior to coronary computed tomography angiography (CCTA). Methods and Results Between February 2008 and April 2011, 732 consecutive patients underwent clinically indicated CCTA. During this ‘control phase’, CCS was performed in all patients. In patients with CCS≥800, CCTA was not performed. During a subsequent ‘CCTA phase’ (May 2011–May 2012) another 200 consecutive patients underwent CCTA, and CCS was performed only in patients with increased probability for severe calcification according to age, gender and atherogenic risk factors. In patients where CCS was not performed, calcium scoring was performed in contrast-enhanced CCTA images. Significant associations were noted between CCS and age (r = 0.30, p<0.001) and coronary risk factors (χ2 = 37.9; HR = 2.2; 95%CI = 1.7–2.9, p<0.001). Based on these associations, a ≤3% pre-test probability for CCS≥800 was observed for males <61 yrs. and females <79 yrs. According to these criteria, CCS was not performed in 106 of 200 (53%) patients during the ‘CCTA phase’, including 47 (42%) males and 59 (67%) females. This resulted in absolute radiation saving of ∼1 mSv in 75% of patients younger than 60 yrs. Of 106 patients where CCS was not performed, estimated calcium scoring was indeed <800 in 101 (95%) cases. Non-diagnostic image quality due to calcification was similar between the ‘control phase’ and the ‘CCTA’ group (0.25% versus 0.40%, p = NS). Conclusion The value of CCS as a filter for identification of a high calcium score is limited in younger patients with intermediate risk profile. Omitting CCS in such patients can contribute to further dose reduction with cardiac CT studies.
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Affiliation(s)
- Gitsios Gitsioudis
- University of Heidelberg, Department of Cardiology, Heidelberg, Germany
- * E-mail:
| | - Waldemar Hosch
- University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg, Germany
| | - Johannes Iwan
- University of Heidelberg, Department of Cardiology, Heidelberg, Germany
| | - Andreas Voss
- University of Heidelberg, Institute of Psychology, Heidelberg, Germany
| | - Edem Atsiatorme
- University of Heidelberg, Department of Cardiology, Heidelberg, Germany
| | - Nina P. Hofmann
- University of Heidelberg, Department of Cardiology, Heidelberg, Germany
| | - Sebastian J. Buss
- University of Heidelberg, Department of Cardiology, Heidelberg, Germany
| | - Stefan Siebert
- University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg, Germany
| | - Hans-Ulrich Kauczor
- University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg, Germany
| | | | - Hugo A. Katus
- University of Heidelberg, Department of Cardiology, Heidelberg, Germany
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Dose reduction in whole-body computed tomography of multiple injuries (DoReMI): protocol for a prospective cohort study. Scand J Trauma Resusc Emerg Med 2014; 22:15. [PMID: 24589310 PMCID: PMC3973884 DOI: 10.1186/1757-7241-22-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 02/22/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Single-pass, contrast-enhanced whole body multidetector computed tomography (MDCT) emerged as the diagnostic standard for evaluating patients with major trauma. Modern iterative image algorithms showed high image quality at a much lower radiation dose in the non-trauma setting. This study aims at investigating whether the radiation dose can safely be reduced in trauma patients without compromising the diagnostic accuracy and image quality. METHODS/DESIGN Prospective observational study with two consecutive cohorts of patients. SETTING A high-volume, academic, supra-regional trauma centre in Germany. STUDY POPULATION Consecutive male and female patients who 1. had been exposed to a high-velocity trauma mechanism, 2. present with clinical evidence or high suspicion of multiple trauma (predicted Injury Severity Score [ISS] ≥16) and 3. are scheduled for primary MDCT based on the decision of the trauma leader on call.Imaging protocols: In a before/after design, a consecutive series of 500 patients will undergo single-pass, whole-body 128-row multi-detector computed tomography (MDCT) with a standard, as low as possible radiation dose. This will be followed by a consecutive series of 500 patients undergoing an approved ultra-low dose MDCT protocol using an image processing algorithm. DATA Routine administrative data and electronic patient records, as well as digital images stored in a picture archiving and communications system will serve as the primary data source. The protocol was approved by the institutional review board. MAIN OUTCOMES (1) incidence of delayed diagnoses, (2) diagnostic accuracy, as correlated to the reference standard of a synopsis of all subsequent clinical, imaging, surgical and autopsy findings, (3) patients' safety, (4) radiation exposure (e.g. effective dose), (5) subjective image quality (assessed independently radiologists and trauma surgeons on a 100-mm visual analogue scale), (6) objective image quality (e.g., contrast-to-noise ratio). ANALYSIS Multivariate regression will be employed to adjust and correct the findings for time and cohort effects. An exploratory interim analysis halfway after introduction of low-dose MDCT will be conducted to assess whether this protocol is clearly inferior or superior to the current standard. DISCUSSION Although non-experimental, this study will generate first large-scale data on the utility of imaging-enhancing algorithms in whole-body MDCT for major blunt trauma. TRIAL REGISTRATION Current Controlled Trials ISRCTN74557102.
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Buss SJ, Schulz F, Mereles D, Hosch W, Galuschky C, Schummers G, Stapf D, Hofmann N, Giannitsis E, Hardt SE, Kauczor HU, Katus HA, Korosoglou G. Quantitative analysis of left ventricular strain using cardiac computed tomography. Eur J Radiol 2014; 83:e123-30. [DOI: 10.1016/j.ejrad.2013.11.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 10/21/2013] [Accepted: 11/23/2013] [Indexed: 10/25/2022]
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Assessment of a model-based, iterative reconstruction algorithm (MBIR) regarding image quality and dose reduction in liver computed tomography. Invest Radiol 2014; 48:598-606. [PMID: 23511193 DOI: 10.1097/rli.0b013e3182899104] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVES The purpose of this study was to assess the image quality of half-dose (HD) liver computed tomography (CT) using a model-based iterative reconstruction algorithm (MBIR) compared with reference dose (RD) using filtered back projection (FBP) and the HD CT images using FBP and adaptive statistical iterative reconstruction (ASIR). MATERIALS AND METHODS A total of 103 patients suspected of having liver metastases underwent liver CT including HD portal venous phase imaging. Among these patients, 73 had undergone RD liver CT reconstructed using FBP, and the HD portal phase CT scans were separately reconstructed using FBP and MBIR. For the other 30 patients, the HD CT images were reconstructed using FBP, ASIR, and MBIR. The CT attenuation coefficients and the mean image noise of various sites, including the liver, the aorta, the main portal vein (MPV), and the subcutaneous fat, were measured, and the contrast-to-noise ratios (CNRs) of the metastatic lesion to the liver and the MPV to the liver were calculated. Two radiologists reviewed each image set with regard to image noise, image quality, lesion conspicuity, and diagnostic acceptability. RESULTS Compared with RD CT, there was a 46.1% decrease in CT dose index volume with HD CT. Image noise was significantly lower in the HD images reconstructed with MBIR than in both the HD FBP images and the RD FBP images (P < 0.001). Compared with the RD FBP and HD FBP images, the CNRs of the metastatic lesion to the liver and the MPV to the liver were higher in the HD MBIR images (P < 0.001). Despite the presence of the unique whirling artifacts of the MBIR images, the HD MBIR images were of good to excellent quality and were not inferior to RD FBP images regarding the lesion conspicuity, the image quality, and the diagnostic acceptability (P > 0.05). Half-dose MBIR also showed less image noise, higher CNRs, and superior image quality compared with HD ASIR (P < 0.001). CONCLUSIONS The HD MBIR images showed less noise, higher CNR, and better image quality than the HD ASIR and HD FBP images did; they also provided less image noise, higher CNR, and similar image quality compared with those of RD FBP images.
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Renker M, Geyer LL, Krazinski AW, Silverman JR, Ebersberger U, Schoepf UJ. Iterative image reconstruction: a realistic dose-saving method in cardiac CT imaging? Expert Rev Cardiovasc Ther 2014; 11:403-9. [DOI: 10.1586/erc.12.178] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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The effect of iterative reconstruction on quantitative computed tomography assessment of coronary plaque composition. Int J Cardiovasc Imaging 2013; 30:155-63. [PMID: 24046026 DOI: 10.1007/s10554-013-0293-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 09/07/2013] [Indexed: 10/26/2022]
Abstract
To compare coronary plaque size and composition as well as degree of coronary artery stenosis on coronary Computed Tomography angiography (CCTA) using three levels of iterative reconstruction (IR) with standard filtered back projection (FBP). In 63 consecutive patients with a clinical indication for CCTA 55 coronary plaques were analysed. Raw data were reconstructed using standard FBP and levels 2, 4 and 6 of a commercially available IR algorithm (iDose(4)). CT attenuation and noise were measured in the aorta and two coronary arteries. Both signal-to-noise-ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The amount of lipid, fibrous and calcified plaque components and mean cross-sectional luminal area were analysed using dedicated software. Image noise was reduced by 41.6% (p < 0.0001) and SNR and CNR in the aorta were improved by 73.4% (p < 0.0001) and 72.9% (p < 0.0001) at IR level 6, respectively. IR improved objective image quality measures more in the aorta than in the coronary arteries. Furthermore, IR had no significant effect on measurements of plaque volume and cross-sectional luminal area. The application of IR significantly improves objective image quality, and does not alter quantitative analysis of coronary plaque volume, composition and luminal area.
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Nance JW, Schoepf UJ, Ebersberger U. The Role of Iterative Reconstruction Techniques in Cardiovascular CT. CURRENT RADIOLOGY REPORTS 2013. [DOI: 10.1007/s40134-013-0023-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Odedra D, Blobel J, AlHumayyd S, Durand M, Jimenez-Juan L, Paul N. Image noise-based dose adaptation in dynamic volume CT of the heart: dose and image quality optimisation in comparison with BMI-based dose adaptation. Eur Radiol 2013; 24:86-94. [DOI: 10.1007/s00330-013-2980-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Revised: 06/29/2013] [Accepted: 07/13/2013] [Indexed: 11/28/2022]
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Williams MC, Weir NW, Mirsadraee S, Millar F, Baird A, Minns F, Uren NG, McKillop G, Bull RK, van Beek EJR, Reid JH, Newby DE. Iterative reconstruction and individualized automatic tube current selection reduce radiation dose while maintaining image quality in 320-multidetector computed tomography coronary angiography. Clin Radiol 2013; 68:e570-7. [PMID: 23838086 PMCID: PMC3807656 DOI: 10.1016/j.crad.2013.05.098] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 05/13/2013] [Accepted: 05/29/2013] [Indexed: 01/22/2023]
Abstract
AIM To assess the effect of two iterative reconstruction algorithms (AIDR and AIDR3D) and individualized automatic tube current selection on radiation dose and image quality in computed tomography coronary angiography (CTCA). MATERIALS AND METHODS In a single-centre cohort study, 942 patients underwent electrocardiogram-gated CTCA using a 320-multidetector CT system. Images from group 1 (n = 228) were reconstructed with a filtered back projection algorithm (Quantum Denoising Software, QDS+). Iterative reconstruction was used for group 2 (AIDR, n = 379) and group 3 (AIDR3D, n = 335). Tube current was selected based on body mass index (BMI) for groups 1 and 2, and selected automatically based on scout image attenuation for group 3. Subjective image quality was graded on a four-point scale (1 = excellent, 4 = non-diagnostic). RESULTS There were no differences in age (p = 0.975), body mass index (p = 0.435), or heart rate (p = 0.746) between the groups. Image quality improved with iterative reconstruction and automatic tube current selection [1.3 (95% confidence intervals (CI): 1.2-1.4), 1.2 (1.1-1.2) and 1.1 (1-1.2) respectively; p < 0.001] and radiation dose decreased [274 (260-290), 242 (230-253) and 168 (156-180) mGy cm, respectively; p < 0.001]. CONCLUSION The application of the latest iterative reconstruction algorithm and individualized automatic tube current selection can substantially reduce radiation dose whilst improving image quality in CTCA.
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Affiliation(s)
- M C Williams
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Edinburgh, UK.
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Tung MK, Cameron JD, Casan JM, Crossett M, Troupis JM, Meredith IT, Seneviratne SK. Radiation dose in 320-slice multidetector cardiac CT: A single center experience of evolving dose minimization. J Cardiovasc Comput Tomogr 2013; 7:157-66. [DOI: 10.1016/j.jcct.2013.05.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 03/30/2013] [Accepted: 05/23/2013] [Indexed: 11/16/2022]
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Iterative Reconstruction Techniques: What do they Mean for Cardiac CT? CURRENT CARDIOVASCULAR IMAGING REPORTS 2013. [DOI: 10.1007/s12410-013-9203-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Hou Y, Zheng J, Wang Y, Yu M, Vembar M, Guo Q. Optimizing radiation dose levels in prospectively electrocardiogram-triggered coronary computed tomography angiography using iterative reconstruction techniques: a phantom and patient study. PLoS One 2013; 8:e56295. [PMID: 23437110 PMCID: PMC3577795 DOI: 10.1371/journal.pone.0056295] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 01/07/2013] [Indexed: 11/18/2022] Open
Abstract
Aim To investigate the potential of reducing the radiation dose in prospectively electrocardiogram-triggered coronary computed tomography angiography (CCTA) while maintaining diagnostic image quality using an iterative reconstruction technique (IRT). Methods and Materials Prospectively-gated CCTA were first performed on a phantom using 256-slice multi-detector CT scanner at 120 kVp, with the tube output gradually reduced from 210 mAs (Group A) to 125, 105, 84, and 63 mAs (Group B–E). All scans were reconstructed using filtered back projection (FBP) algorithm and five IRT levels (L2-6), image quality (IQ) assessment was performed. Based on the IQ assessment, Group D(120 kVp, 84 mAs) reconstructed with L5 was found to provide IQ comparable to that of Group A with FBP. In the patient study, 21 patients underwent CCTA using 120 kV, 210 mAs with FBP reconstruction (Group 1) followed by 36 patients scanned with 120 kV, 84 mAs with IRT L5 (Group 2). Subjective and objective IQ and effective radiation dose were compared between two groups. Results In the phantom scans, there were no significant differences in image noise, contrast-to-noise ratio (CNR) and modulation transfer function (MTF) curves between Group A and the 84 mAs, 63 mAs groups (Groups D and E). Group D (120 kV, 84 mAs and L5) provided an optimum balance, producing equivalent image quality to Group A, at the lowest possible radiation dose. In the patient study, there were no significant difference in image noise, signal-to-noise ratio (SNR) and CNR between Group 1 and Group 2 (p = 0.71, 0.31, 0.5, respectively). The effective radiation dose in Group 2 was 1.21±0.14 mSv compared to 3.20±0.58 mSv (Group 1), reflecting dose savings of 62.5% (p<0.05). Conclusion iterative reconstruction technique used in prospectively ECG-triggered 256-slice coronary CTA can provide radiation dose reductions of up to 62.5% with acceptable image quality.
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Affiliation(s)
- Yang Hou
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Jiahe Zheng
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yuke Wang
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Mei Yu
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Mani Vembar
- CT Clinical Science Philips Healthcare, Cleveland, Ohio, United States of America
| | - Qiyong Guo
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China
- * E-mail:
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Hosch W, Hofmann NP, Mueller D, Iwan J, Gitsioudis G, Siebert S, Giannitsis E, Kauczor HU, Katus HA, Korosoglou G. Body mass index-adapted prospective coronary computed tomography angiography. Determining the lowest limit for diagnostic purposes. Eur J Radiol 2013; 82:e232-9. [PMID: 23332891 DOI: 10.1016/j.ejrad.2012.12.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Revised: 12/17/2012] [Accepted: 12/22/2012] [Indexed: 10/27/2022]
Abstract
PURPOSE To investigate the value of 4 different protocols for prospectively triggered 256-slice coronary computed tomography angiography (coronary CTA). METHODS Two hundred and ten patients underwent prospectively triggered coronary CTA for suspected or known coronary artery disease (CAD). Patients with heart rate >75 bps before the scan despite ß-blocker administration and with arrhythmia were excluded. From January to September 2010, 60 patients underwent coronary CTA using a non-tailored protocol (120 kV; 200 mAs) and served as our 'control' group. From September 2010 to April 2012, based on the body mass index (BMI) of the examined patients (BMI subgroups of <25; 25-28; 28-30, and ≥ 30 kg/m(2)) current tube voltage and tube current were: (1) slightly, (2) moderately or (3) strongly reduced, resulting into the 3 following BMI-adapted acquisition groups: (1) a 'standard' (100/120 kV; 100-200 mAs; n=50), 2) a 'low dose' (100/120 kV; 75-150 mAs; n=50), and 3) an 'ultra-low dose' (100/120 kV; 50-100 mAs; n=50) protocol. RESULTS Patients examined using the non-tailored protocol exhibited the highest radiation exposure (3.2 ± 0.4 mSv), followed by the standard (1.6 ± 0.7 mSv), low-dose (1.2 ± 0.6 mSv) and ultra-low dose protocol (0.7 ± 0.3 mSv) (radiation savings of 50%, 63% and 78% respectively). Overall image quality was similar with standard dose (1.9 ± 0.6) and low-dose (2.0 ± 0.5) compared to the non-tailored group (1.9 ± 0.5) (p=NS for all). In the ultra-low dose group however, image quality was significant reduced (2.7 ± 0.6), p<0.05 versus all other groups). CONCLUSION Using BMI-adapted low dose acquisitions image quality can be maintained with simultaneous radiation savings of ∼65% (dose of ∼1 mSv). This appears to be the lower limit for diagnostic coronary CTA, whereas ultra-low dose acquisitions result in significant image degradation.
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Affiliation(s)
- Waldemar Hosch
- University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg, Germany.
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HMGB1 is associated with atherosclerotic plaque composition and burden in patients with stable coronary artery disease. PLoS One 2012; 7:e52081. [PMID: 23284878 PMCID: PMC3524090 DOI: 10.1371/journal.pone.0052081] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 11/08/2012] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVES The role of inflammation in atherosclerosis is widely appreciated. High mobility group box 1 (HMGB1), an injury-associated molecular pattern molecule acting as a mediator of inflammation, has recently been implicated in the development of atherosclerosis. In this study, we sought to investigate the association of plasma HMGB1 with coronary plaque composition in patients with suspected or known coronary artery disease (CAD). DESIGN HMGB1, high sensitive troponin T (hsTnT) and high sensitive C-reactive protein (hsCRP) were determined in 152 consecutive patients with suspected or known stable CAD who underwent clinically indicated 256-slice coronary computed tomography angiography (CCTA). Using CCTA, we assessed 1) coronary calcification, 2) non-calcified plaque burden and 3) the presence of vascular remodeling in areas of non-calcified plaques. RESULTS Using univariate analysis, hsCRP, hsTnT and HMGB1 as well as age, and atherogenic risk factors were associated with non-calcified plaque burden (r = 0.21, p = 0.009; r = 0.48, p<0.001 and r = 0.34, p<0.001, respectively). By multivariate analysis, hsTnT and HMGB1 remained independent predictors of the non-calcified plaque burden (r = 0.48, p<0.01 and r = 0.34, p<0.001, respectively), whereas a non-significant trend was noticed for hs-CRP (r = 0.21, p = 0.07). By combining hsTnT and HMGB1, a high positive predictive value for the presence of non-calcified and remodeled plaque (96% and 77%, respectively) was noted in patients within the upper tertiles for both biomarkers, which surpassed the positive predictive value of each marker separately. CONCLUSIONS In addition to hs-TnT, a well-established cardiovascular risk marker, HMGB1 is independently associated with non-calcified plaque burden in patients with stable CAD, while the predictive value of hs-CRP is lower. Complementary value was observed for hs-TnT and HMGB1 for the prediction of complex coronary plaque.
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Li JL, Huang MP, Liang CH, Zhao ZJ, Liu H, Cui YH, Liu QS, Zhang JE, Yang L, Ivanc TB, Yanof JH. Individualized radiation dose control in 256-slice CT coronary angiography (CTCA) in retrospective ECG-triggered helical scans: Using a measure of body size to adjust tube current selection. Eur J Radiol 2012; 81:3146-53. [DOI: 10.1016/j.ejrad.2012.04.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Revised: 04/20/2012] [Accepted: 04/21/2012] [Indexed: 12/01/2022]
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Impact of iterative reconstruction on CNR and SNR in dynamic myocardial perfusion imaging in an animal model. Eur Radiol 2012; 22:2654-61. [DOI: 10.1007/s00330-012-2525-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 04/20/2012] [Accepted: 04/27/2012] [Indexed: 10/28/2022]
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Quantitative analysis of left ventricular dyssynchrony using cardiac computed tomography versus three-dimensional echocardiography. Eur Radiol 2012; 22:1303-9. [PMID: 22270144 DOI: 10.1007/s00330-011-2375-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 11/22/2011] [Accepted: 12/12/2011] [Indexed: 02/03/2023]
Abstract
OBJECTIVES We investigated whether cardiac computed tomography (CCT) can determine intraventricular dyssynchrony in comparison to real-time three-dimensional echocardiography (RT3DE) in patients who are considered for cardiac resynchronisation therapy (CRT). METHODS 35 patients considered for CRT were examined. Left ventricular (LV) dyssynchrony was quantified by calculating the standard deviation index (SDI) of 17 myocardial LV segments by RT3DE and ECG-gated contrast-enhanced 64-slice dual-source CCT. For both analyses the same software algorithm (4D LV-Analysis) was used. RESULTS Close correlations were observed for end-systolic volume, end-diastolic volume and LV ejection fraction between the two techniques (r = 0.94, r = 0.92 and r = 0.95, respectively, P < 0.001 for all). For the global dyssynchrony index SDI, a high correlation was found between RT3DE and CCT (r = 0.84, P < 0.001), which further increased after exclusion of segments with poor image quality by echocardiography (r = 0.90, P < 0.001). The required time for quantitative analysis was significantly shorter (162 ± 22 s vs. 608 ± 112 s per patient, P < 0.001) and reproducibility was significantly higher for CCT compared with RT3DE (interobserver variability of 4.5 ± 3.1% vs. 7.9 ± 6.1%, P < 0.05). CONCLUSION Quantitative assessment of LV dyssynchrony is feasible by CCT. Owing to its higher reproducibility and faster analysis time compared with RT3DE, this technique may represent a valuable alternative for dyssynchrony assessment. KEY POINTS • Quantitative assessment of left ventricular dyssynchrony is feasible by cardiac computed tomography (CCT). • This technique has been compared with real-time three-dimensional echocardiography (RT3DE). • Reproducibility is significantly higher for CCT compared with RT3DE. • Time spent for analysis is significantly shorter for CCT. • Computed tomography may represent a valuable alternative to ultrasound for dyssynchrony assessment.
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Conservatively treated incidental aneurysm of the distal left main coronary artery: detection by coronary angiography and noninvasive followup using coronary computed tomography angiography. Case Rep Cardiol 2012; 2012:547318. [PMID: 24826261 PMCID: PMC4008280 DOI: 10.1155/2012/547318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 05/14/2012] [Indexed: 12/03/2022] Open
Abstract
Coronary artery aneurysms are relatively rare and commonly associated with significant coronary artery disease (CAD), inflammatory diseases (Kawasaki syndrome, infection), or iatrogenic complications. Herein, we report an unusual case of an incidental coronary aneurysm of the left main artery in a patient without specific clinical symptoms of myocardial ischemia or systemic inflammation and without angiographically significant CAD. Angiographic images are provided, acquired during cardiac catheterization, as well as coronary computed tomography angiography (CCTA) images obtained at 1 year of followup.
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