Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 7, 2015; 21(1): 214-220
Published online Jan 7, 2015. doi: 10.3748/wjg.v21.i1.214
Monochromatic energy computed tomography image for active intestinal hemorrhage: A model investigation
Wen-Dong Liu, Xing-Wang Wu, Jun-Mei Hu, Bin Wang, Bin Liu
Wen-Dong Liu, Xing-Wang Wu, Jun-Mei Hu, Bin Liu, Department of Radiology, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, Anhui Province, China
Bin Wang, Department of Epidemiology and Statistics, Anhui Medical University, Hefei 230022, Anhui Province, China
Author contributions: Liu WD, Wu XW contributed equally to this work; Wu XW designed and performed research; Liu WD wrote the paper and analyzed data; Hu JM analyzed data; Liu B provided technical support and revised this paper; Wang B provided statistical support.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Bin Liu, MD, Department of Radiology, the First Affiliated Hospital of Anhui Medical University, Jixi Road, Hefei 230022, Anhui Province, China. liubin1305@126.com
Telephone: +86-551-62922396 Fax: +86-551-62922396
Received: May 20, 2014
Peer-review started: May 22, 2014
First decision: July 21, 2014
Revised: July 31, 2014
Accepted: September 12, 2014
Article in press: September 16, 2014
Published online: January 7, 2015
Abstract

AIM: To investigate the value of computed tomography (CT) spectral imaging in the evaluation of intestinal hemorrhage.

METHODS: Seven blood flow rates were simulated in vitro. Energy spectral CT and mixed-energy CT scans were performed for each rate (0.5, 0.4, 0.3, 0.2, 0.1, 0.05 and 0.025 mL/min). The detection rates and the contrast-to-noise ratios (CNRs) of the contrast agent extravasation regions were compared between the two scanning methods in the arterial phase (AP) and the portal venous phase (PVP). Comparisons of the CNR values between the PVP and the AP were made for each energy level and carried out using a completely random t test. A χ2 test was used to compare the detection rates obtained from the two scanning methods.

RESULTS: The total detection rates for energy spectral CT and mixed-energy CT in the AP were 88.57% (31/35) and 65.71% (23/35), respectively, and the difference was significant (χ2 = 5.185, P = 0.023); the total detection rates in the PVP were 100.00% (35/35) and 91.4% (32/35), respectively, and the difference was not significant (χ2 = 1.393, P = 0.238). In the AP, the CNR of the contrast agent extravasation regions was 3.58 ± 2.09 on the mixed-energy CT images, but the CNRs were 8.78 ± 7.21 and 8.83 ± 6.75 at 50 and 60 keV, respectively, on the single-energy CT images, which were significantly different (3.58 ± 2.09 vs 8.78 ± 7.21, P = 0.031; 3.58 ± 2.09 vs 8.83 ± 6.75, P = 0.029). In the PVP, the differences between the CNRs at 40, 50 and 60 keV different monochromatic energy levels and the polychromatic energy images were significant (19.35 ± 10.89 vs 11.68 ± 6.38, P = 0.010; 20.82 ± 11.26 vs 11.68 ± 6.38, P = 0.001; 20.63 ± 10.07 vs 11.68 ± 6.38, P = 0.001). The CNRs at the different energy levels in the AP and the PVP were significantly different (t = -2.415, -2.380, -2.575, -2.762, -2.945, -3.157, -3.996 and -3.189).

CONCLUSION: Monochromatic energy imaging spectral CT is superior to polychromatic energy images for the detection of intestinal hemorrhage, and the detection was easier in the PVP compared with the AP.

Keywords: Spectral imaging, Computed tomography, Monochromatic energy imaging, Small bowel bleeding

Core tip: Recent technical advances,including monochromatic energy image spectral computed tomography (CT) with its accurate material-decomposition images and monochromatic spectral images at energy levels, are only rarely included in intestinal hemorrhage studies. This paper aimed to verify the diagnostic value of spectral CT in small bowel bleeding.