Material and Method: Between October 2008 and May 2010, included the consecutive 75 patients/76 CT studies who underwent multidetector CT at Siriraj Hospital to rule out bowel obstruction. Fifty-seven patients of 58 studies confirmed the final diagnosis of bowel obstruction by surgical proof or obstructive symptoms relief from conservative treatments; divided into 25 small bowel and 33 large bowel obstructions. Two independent readers, blinded to diagnosis, interpreted for bowel obstruction firstly using axial slices alone, then immediately scoring MPR images including axial, coronal, sagittal, and oblique reformations from the same study. Confidence score was applied. In case of radiological diagnosis of bowel obstruction, the findings of transition point, cause, severity, and complication were also evaluated.

Results: CT diagnosis of bowel obstruction was made 54 on axial image alones and 55 on axial image plus MPR, leading to the sensitivity of 93.1% and specificity of 77.8% on the axial scans alone and the sensitivity of 94.8% and specificity of 72.2% on the axial plus MPR, respectively. The axial plus MPR images helped correct diagnosis and increased confidence score in one case of low grade, small bowel obstruction. Accuracy in diagnosis of between large bowel obstruction and small bowel obstruction was 90% and 88.5% on axial scans alone and 90% and 92.3% on axial plus MPR scans, respectively.

Conclusion: The axial scan CT is an appropriate modality for the patients suspected bowel obstruction. The authors encourage using MPR as the adjunct tool to the axial images, especially in the case suspected small bowel obstruction. MPR help increasing diagnostic confidence and confirming the findings found on axial image.

Keywords: Bowel obstruction, Multiplanar reformations (MPR)