Magnetic Resonance Imaging of Bowel Ischemia Induced by Ligation of Superior Mesenteric Artery and Vein in a Cat Model

Abstract

Objective: To assess the usefulness of magnetic resonance (MR) imaging for detecting bowel ischemia with strangulation compared with histopathologic findings in an experimental cat model. Materials and Methods: Fourteen cats were assigned to the normal control group (n = 3), acute ischemic group (induced by ligation of superior mesenteric vessels for 3 hours, n = 7), and subacute ischemic group (induced by ligation of superior mesenteric vessels for 10 hours, n = 4). Using a 4.7-T MR scanner, contrast-enhanced T1-weighted images were obtained at 0, 10, 20, 30, and 60 minutes after bolus injection of contrast media. T1- and T2-weighted images were obtained from the extracted bowel wall and compared with histopathologic findings. Results: On contrast-enhanced MR images, the target-like bowel wall layers were clearly demonstrated and the submucosal layer showed the most prominent enhancement. At 10 minutes after administration of contrast media, the subacute ischemic group showed significantly lower enhancement of the submucosal layer than the normal or acute ischemic group (P <0.05). On T1-weighted images, there were not significant differences between the normal and ischemic bowel groups (P >0.05). On T2-weighted images, the signal intensity of all layers of acute ischemic bowel wall was significantly higher than that of the normal control or subacute ischemic group (P <0.05). Conclusion: Delayed contrast-enhanced MR images and T2-weighted images were helpful for detecting subacute and acute bowel ischemia with strangulation, respectively.