Anatomy of the right anterosuperior area (segment 8) of the liver: evaluation with helical CT during arterial portography.

PURPOSE: To evaluate the segmental anatomy of the right anterosuperior area (segment 8) of the liver by using helical computed tomography during arterial portography (CTAP). MATERIALS AND METHODS: Twenty-seven patients without lesions at segment 8 underwent helical CTAP. Three-dimensional portograms were reconstructed to verify the course of the portal veins. The number of subsegmental branches, in addition to the branching point and the distribution in segment 8, was assessed. RESULTS: In 25 (93%) patients, the dorsal branch of segment 8 gave rise to dorsally directed branches posterior to the right hepatic vein. In only four (25%) of 16 patients in whom the medial branch of segment 8 arose near the porta hepatis, the long paracaval portal branch of the caudate lobe extended upward above the interval between the middle and right hepatic veins. CONCLUSION: In most of the patients, the dorsal branches of segment 8 supplied the dorsocranial area of the right lobe posterior to the right hepatic vein. The par...