Location of the transition zone in CT of small-bowel obstruction: added value of multiplanar reformations

To assess the additional value of multiplanar reformations (MPR) in comparison with axial images alone for location of the transition zone in CT of mechanical small-bowel obstruction (SBO). Sixty-nine consecutive patients with mechanical SBO underwent 16-slice multi detector row CT (MDCT). The gold standard for the precise location of the transition zone was established by two experienced abdominal radiologists, unblinded to clinical and surgical reports, reviewing all CT examinations. On a workstation, two blinded readers independently located the transition zone using first axial slices alone and then 1 month later MPR (axial, coronal, sagittal and oblique views) according to a three-point confidence scale. Diagnostic accuracy and mean confidence score were evaluated for both the transverse and multiplanar data sets. Accuracy of transition zone location for reader 1 and reader 2 was 86% and 84% with axial slices alone, and by using MPR 93% (significant: P = 0.03) and 90% (not significant: P = 0.08), respectively. Mean confidence score was significantly increased for both readers using MPR: 0.3 higher (P = 0.0001) and 0.37 higher (P = 0.0001) respectively. MPR can increase both accuracy and confidence in the location of the transition zone in CT of SBO.