Acute arterial mesenteric ischemia and reperfusion: macroscopic and MRI findings, preliminary report

To explore the physiopathology and magnetic resonance imaging (MRI) findings in an animal model of acute arterial mesenteric ischemia (AAMI) with and without reperfusion. METHODS: In this study, 8 adult Sprague-Dawley rats underwent superior mesenteric artery (SMA) ligation and were then randomly divided in two groups of 4. In group I, the ischemia was maintained for 8 h. In group II, 1-h after SMA occlusion, the ligation was removed by cutting the thread fixed on the back of the animal, and reperfusion was monitored for 8 h. MRI was performed using a 7-T system. RESULTS: We found that, in the case of AAMI without reperfusion, spastic reflex ileus, hypotonic reflex ileus, free abdominal fluid and bowel wall thinning are present from the second hour, and bowel wall hyperintensity in T2-W sequences are present from the fourth hour. The reperfusion model shows the presence of early bowel wall hyperintensity in T2-W sequences after 1 h and bowel wall thickening from the second hour. CONCLUSION: Our study has shown that MRI can assess pathological changes that occur in the small bowel and distinguish between the presence and absence of reperfusion after induced acute arterial ischemia.