Imaging bowel obstruction: a comparison between fast magnetic resonance imaging and helical computed tomography.

AIM: To compare the accuracy of fast magnetic resonance (MR) imaging using the half-Fourier single shot turbo spin echo (HASTE) sequence with helical computed tomography (CT) in diagnosing bowel obstruction.

MATERIALS AND METHODS: Prospective evaluation of 44 patients with clinical evidence of bowel obstruction was conducted using various investigations including HASTE MR and helical CT. MR was performed with a Siemens 1.5 Tesla MR Imaging System and CT was performed with one of two Siemens ARHP CT systems using helical technique. MR acquisition allowed data to be gathered in 6-10 minutes and no contrast media were administered. CT imaging consisted of consecutive helical CT through the abdomen and pelvis with oral and intravenous contrast medium used when indicated. Bowel dilation along with the presence and level of obstruction were determined.

RESULTS: Twenty-eight patients had bowel obstruction confirmed at laparotomy or by radiographic assessment. Of these, 25 had small bowel obstruction and three had colonic obstructions. The obstruction was due to fibrous adhesions in nine patients, metastases or primary carcinoma in seven, Crohn's disease in four, hernias in two, and inflammation or abscess in two. Other causes of obstruction included lymphoma, intussusception and anastomotic stricture. The cause of obstruction was correctly diagnosed by CT in 71%, and by MR in 95% of cases. The sensitivity, specificity and accuracy for HASTE MR imaging was 95%, 100% and 96% respectively as compared to 71%, 71% and 71% for helical CT.

CONCLUSION: Fast MR imaging using the HASTE sequence is more accurate than helical CT in diagnosing bowel obstruction.