[Magnetic resonance imaging of the small intestine and colon in Crohn's disease].

Three normal volunteers and 20 patients with known Crohn's disease were examined with MRI--at 0.5 Tesla and with a superconductive magnet. Coronal T1-weighted GE images were mainly acquired, before and after i.v. Gd-DTPA injection in breath hold (TR 70 ms, TE 13 ms, FA 70 degrees). MR findings were compared with the results of small and large bowel enema. In 6 patients (30\%) the abnormal loops were missed. In the other 14 patients (70\%) MRI did depict the affected loops in the same sites as depicted by conventional radiography. The bowel wall was thickened (4-10 mm) in all patients. In 10 patients the thickened wall was markedly enhanced after Gd-DTPA injection. In 6 patients MRI demonstrated disease complications--i.e., stenoses, fistulae and abscesses--missed by conventional radiography. In 7 patients MRI showed the bowel to be more involved than demonstrated by conventional studies. Bowel wall thickening appeared to be a constant and reliable sign of disease. Wall enhancement was a less frequent sign but, when present, it was considered as characteristic as wall thickening. In the staging of Crohn's disease, MRI yields more pieces of information than conventional radiography and depicts the involvement of the intestinal wall and of its surrounding spaces.