Spiegel's lobe bile ducts often drain into the right hepatic duct or its branches: study using drip-infusion cholangiography-computed tomography in 179 consecutive patients.

Using drip-infusion cholangiography-computed tomography (DIC-CT), we successfully identified the bile ducts draining the caudate lobe in 138 of 179 consecutive patients with extrahepatic cholelithiasis (179 ducts from Spiegel's lobe and 154 from the paracaval portion; 1-5 ducts per patient). The dorsal subsegmental duct of S8 (B8c) was often identified and could be discriminated from the paracaval caudate ducts, thus acting as a landmark for the right margin of the caudate lobe. Notably, in more than one-third of the 138 patients, at least one of the Spiegel's lobe ducts drained into the right hepatic duct or its branches (30.2% of the 179 ducts overall; all ducts joined branches of the right lobe in 25 patients). Similarly, 34.4% of the 154 paracaval caudate lobe ducts drained into the left hepatic duct or its branches. These "anatomical left/right dissociations" between the drainage territory and route were much more frequent than previously reported. Our results confirm the effectiveness of DIC-CT as a classical, noninvasive method for presurgical evaluation of the biliary system, but they also suggest that anatomical partial resection of the dorsal liver in patients with hilar cholangioma is often impossible because of contralateral biliary drainage.