Variations in liver-colon anatomic relationship: relevance to interventional radiology.

PURPOSE: To determine the prevalence of significant variations in liver-colon anatomy in an unselected patient population and evaluate the potential effect of these variations on liver-related interventional procedures. PATIENTS AND METHODS: All abdominal computed tomographic (CT) scans were reviewed prospectively over a 4-month period. Cases that revealed variant hepatocolic anatomy were selected and analyzed for the position of the colon, gallbladder, and duodenum; liver morphology; and the anatomic relations of the right portal vein. RESULTS: Seventeen (3.3%) of 517 abdominal CT scans demonstrated variant hepatocolic anatomic relations. In seven cases, liver lobar morphology was normal, but the colon was interposed between the chest wall and the liver. The remaining 10 cases were characterized by hypoplasia or aplasia of one or both segments of the left lobe. In these cases the right portal vein was anteriorly exposed and was close to the gallbladder and transverse colon. In all 17 cases it was qualitatively judged that technical modifications might be needed in the performance of various interventional procedures, including percutaneous biliary drainage, biopsies, and transjugular intrahepatic portosystemic shunt creation. CONCLUSION: Variations in liver-colon anatomic relations in isolation or secondary to hepatic developmental anomalies may have a significant potential impact on the performance of various fluoroscopically guided hepatobiliary interventional procedures.