Delineation of the watershed between right and left hepatic arterial territories with carbon dioxide-enhanced ultrasonography.

PURPOSE

To delineate the watersheds between hepatic arterial territories and their variations with the use of CO(2)-enhanced ultrasonography (US) and to compare the results with segmental anatomy as described by Couinaud.

MATERIALS AND METHODS

From March 2004 to January 2005, this study recruited 31 patients (18 men and 13 women; mean age, 63 years; range, 47-77 y) with hepatocellular carcinoma (HCC) who were scheduled to receive transarterial chemoembolization. After serial angiography, CO(2)-enhanced US was performed with catheters superselectively inserted into the hepatic arteries. The territorial divisions between hepatic arteries were compared with the anatomic courses of the middle and left hepatic veins. Data from 17 patients were used to assess the vascular territories of the right and left lobe and data from the remaining 14 patients were used to assess those of the left medial and left lateral segments.

RESULTS

Mapped arterial territories exactly matched Couinaud segments in 17 of 31 patients (54.8%). They did not coincide with Couinaud segments in 45.2% of patients with HCC. Crossover enhancement was noted over the right and left lobes and over the left medial and lateral segments in seven patients each. Two tumors located exactly in watershed areas showed CO(2) enhancement across the hepatic vein.

CONCLUSIONS

CO(2)-enhanced US is useful to delineate arterial territories of hepatic segments and show crossover arterial supply compared with Couinaud segments. Awareness of crossover arterial supply is important for chemoembolization, segmental chemoembolization, hepatic arterial infusion, sonography, and surgery.