Recombination fraction estimate of zero in the presence of apparent recombinants: effects of incomplete penetrance and sporadic cases

The purpose of this study was to assess the potential role of MR imaging with polylysine-Gd-DTPA enhancement in the early detection of acute occlusive intestinal ischemia in a rat model. After devascularization of the distal ileum in 12 rats, T2-weighted fast spin-echo MR images were acquired, followed by T1-weighted images before and after IV administration of 0.1 mmol/kg polylysine-Gd-DTPA. The signal intensity of the ischemic intestine did not differ significantly from that of the normal intestine before the administration of the contrast material. No mucosal or submucosal edema or hemorrhage was found in the ischemic intestine at histologic examination. After the administration of polylysine-Gd-DTPA, the ischemic intestine lacked enhancement and its signal intensity was significantly lower than that of the normal intestine. MR imaging with polylysine-Gd-DTPA enhancement can detect acute occlusive ischemia of the rat intestine at an early stage.