CT diagnosis of the nature of bowel obstruction: morphological evaluation of the transition point

PURPOSE: This study evaluated transition-point morphology for defining the nature of bowel obstructions. MATERIALS AND METHODS: Computed tomography (CT) examinations of 95 patients affected by severe bowel obstruction (23 neoplastic, 72 nonneoplastic) were retrospectively reviewed. RESULTS: The transition point was identified in 89 patients (94%); morphology in relation to the proximal loop was concave in 64 cases (68%), linear in five (5%) and convex in 20 (21%). Concave transition-point morphology was indicative of a nonneoplastic condition, with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy values of 89%, 100%, 100%, 74% and 92%, respectively. A linear shape had almost identical incidence among neoplastic (60%) and nonneoplastic (40%) conditions. A convex appearance correlated with neoplastic disease with sensitivity, specificity, PPV, NPV and diagnostic accuracy values of 87%, 100%, 100%, 96% and 97%, respectively. CONCLUSIONS: In the case of bowel obstruction, transitionpoint detection indicates the obstruction site, whereas its morphological evaluation can contribute to defining the nature of the obstruction. A concave morphology indicates a nonneoplastic condition with a high probability; a convex morphology correlates with neoplastic disease, whereas linearity is not significant.