Hepatic pseudolesion in the left lobe around the falciform ligament at helical CT.
To determine the prevalence and possible cause of pseudolesions in the left hepatic lobe around the falciform ligament at hepatic helical computed tomography (CT). Portal venous-dominant CT scans of 472 consecutive patients were reviewed. CT of the left hepatic lobe was performed after injection of contrast material into the portal vein in 73 patients, the hepatic artery in 32, and the internal thoracic artery in four. The scans were compared with those obtained at helical CT, and the findings were analyzed. Pseudolesions were seen on 64 (14%) of 472 helical CT scans and correlated well (accuracy, 96%) with portal perfusion defects. They were not more enhanced than the surrounding liver parenchyma at CT arteriography with hepatic artery injection but were enhanced in two patients at CT arteriography with internal thoracic artery injection. Pseudolesions are caused by portal perfusion defects and may receive an aberrant blood supply.