Diagnosis by 64-Row Multidetector Computed Tomography for Longitudinal Superficial Extension of Distal Cholangiocarcinoma

Background: This study aimed to demonstrate the diagnostic ability of 64-row multidetector computed tomography (64-row MDCT) for longitudinal superficial extension of distal cholangiocarcinoma (LSEDC). Methods: Twenty-seven patients with distal cholangiocarcinoma (DC) underwent preoperative 64-row MDCT without drainage tubes. LSEDC was diagnosed using curved planar reconstruction images reconstructed from 64-row MDCT, which were compared with pathologic findings. Results: LSEDC was observed in 13 patients (48%). Ten patients (37%) had enhancing nonthickened bile ducts extending continuously from the main tumor (type 1). These coincided with pathologic findings of high-grade dysplasia (HGD) in 90.0% of cases; that is, a positive predictive value (9/10). Fourteen patients (52%) had only wall thickening of the main tumor with or without enhancement (type 2). Four patients with HGD in this group were difficult to diagnose. Three patients (11%) had enhancing nonthickened bile ducts not in continuity with the main tumor (type 3). This finding revealed an inflammatory change instead of a carcinoma in the pathologic findings. The sensitivity and specificity of detecting HGD were 75% and 93% on the liver side, 33% and 100% on the duodenal side, respectively. Four patients (67%) with HGD on the liver side were overdiagnosed, and one patient (17%) was underdiagnosed. Most of the patients overdiagnosed on the liver side (3/4 or 75%) had drainage tubes inserted before the MDCT. Conclusions: For DC patients without drainage tubes, the 64-row MDCT technique may be useful for diagnosing HGD depicted as LSEDC on the liver side but not as useful on the duodenal side.