Figures 11, 12. Nodular ductal cholangiocarcinoma. (11) Subcostal oblique US scan through the ductal confluence shows diffuse, shelflike thickening of the proximal right hepatic duct (arrowheads). A small residual lumen remains visible. (12) Sagittal (a) and transverse (b) US scans through the common duct show sheetlike thickening of the common hepatic duct (shouldering of tumor [s and arrowheads in a]) with a corresponding "bull's-eye" appearance of the common hepatic duct on the transverse scan (arrows in b). Histopathologic findings helped confirm nodular cholangiocarcinoma. ha = hepatic artery, pv = portal vein.