Helical CT with CT angiography in assessing periampullary neoplasms: identification of vascular invasion.

PURPOSE To determine the accuracy of helical computed tomography (CT) with CT angiography in identifying vascular invasion by periampullary neoplasms and to assess the added value of CT angiography. MATERIALS AND METHODS Sixty-nine patients suspected of having periampullary neoplasms were examined. Images from dual phase helical CT with CT angiography were compared with surgical findings in 36 patients. Arterial and venous invasion were assessed separately. Accuracy, positive predictive value (PPV), and negative predictive value (NPV) were determined for CT alone and for CT supplemented with CT angiography. RESULTS The accuracy, PPV, and NPV of helical CT with CT angiography in identifying venous invasion was 92% (33 of 36 patients), 86% (12 of 14 patients), and 95% (21 of 22 patients), respectively. When transverse CT images alone were analyzed, accuracy decreased to 69% (25 of 36 patients) (P =.005); PPV and NPV were 63% (five of eight patients) and 71% (20 of 28 patients), respectively. When identifying arterial invasion, the accuracy of CT with CT angiography and of CT alone was 86% (31 of 36 patients). PPV and NPV also were identical at 71% (five of seven patients) and 90% (26 of 29 patients), respectively. CONCLUSION CT angiography significantly increases the ability to identify venous invasion when compared with CT alone but does not improve detection of arterial invasion.