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. Group I u...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. Group I underwent inferior mesenteric artery （IMA） ligation followed by macroscopic observa- tions and histological analysis. In group H, 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 wors-ened 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 lat- ter 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 hyper- intensity associated with a reduction in peritoneal free fluid. The 7T-MRI findings were correlated with histolog- ical alterations, varying from an attenuated epithelium with glandular apex lesions at 1 h to coagulative necro- sis 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.展开更多
文摘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. Group I underwent inferior mesenteric artery （IMA） ligation followed by macroscopic observa- tions and histological analysis. In group H, 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 wors-ened 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 lat- ter 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 hyper- intensity associated with a reduction in peritoneal free fluid. The 7T-MRI findings were correlated with histolog- ical alterations, varying from an attenuated epithelium with glandular apex lesions at 1 h to coagulative necro- sis 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.
