Magnetic resonance imaging:A new tool for diagnosis of acute ischemic colitis?

AIM:To define the evolution of ischemic lesions with 7T magnetic resonance imaging(7T-MRI)in an animal model of acute colonic ischemia.METHODS:Adult Sprague-Dawley rats were divided into two groups.GroupⅠ underwent inferior mesenteric artery(IMA)ligation followed by macroscopic observations and histological analysis.In groupⅡ,7T-MRI was performed before and after IMA ligation and followed by histological analysis.RESULTS:Morphological alterations started to develop 1 h after IMA ligation,when pale areas became evident in the splenic flexure mesentery and progressively worsened up to 8 h thereafter,when the mesentery was less pale,and the splenic flexure loop appeared very dark.The 7T-MRI results reflected these alterations,showing a hyperintense signal in both the intraperitoneal space and the colonic loop wall 1 h after IMA ligation;the latter progressively increased to demonstrate a reduction in the colonic loop lumen at 6 h.Eight hours after IMA ligation,MRI showed a persistent colonic mural hyperintensity associated with a reduction in peritoneal free fluid.The 7T-MRI findings were correlated with histological alterations,varying from an attenuated epithelium with glandular apex lesions at 1 h to coagulative necrosis and loss of the surface epithelium detected 8 h after IMA ligation.CONCLUSION:MRI may be used as a substitute for invasive procedures in diagnosing and grading acute ischemic colitis,allowing for the early identification of pathological findings.