Multi-detector CT in peritoneal carcinomatosis: diagnostic role of thin slices and multiplanar reconstructions

Background  In order to investigate whether 1-mm thin slices and multiplanar reconstructions (MPRs) of multi-detector computed tomography (CT) datasets interpreted in addition to isotropic 5-mm thick slices in one session improve the detection of peritoneal carcinomatosis. Methods  The abdominal CT datasets of 44 patients with histologically proven tumors of the abdomen or pelvis were retrospectively evaluated for peritoneal carcinomatosis by four radiologists with variable experience (radiologist 1: ≥10 years, radiologists 2 and 3: 1.5 years, radiologist 4: 0.5 years). In three successive steps, the radiologists evaluated first the axial 5-mm slices, second the 1-mm slices, and third the MPRs and rated their diagnostic confidence. Results  Specificity was nearly unchanged for all the four radiologists. Sensitivity improved for the most experienced and the least experienced radiologists and was unchanged for the two readers with intermediate skills. Except for the third step of radiologist 4, no statistically significant differences in diagnostic performance were detected. The diagnostic confidence of all the four readers benefited to variable degrees from interpretation of the 1-mm slices and MPRs. Conclusions  While 5-mm slices are sufficient for the detection of peritoneal carcinomatosis, 1-mm slices and MPRs can improve sensitivity and diagnostic confidence.