Intrahepatic arterioportal shunt: helical CT findings

The purpose of this study was to characterize the appearance of intrahepati c arterioportal shunts (APS) on two-phase helical CT, with emphasis on the importance of the hepatic arterial-dominant phase (HAP) to demonstrate perf usion disorders. We review eight cases of APS diagnosed by helical CT in ou r institution from January 1996 to March 1997 and describe the CT findings that established diagnosis. Five of them were confirmed by angiography. In seven (87.5 %) cases of APS we found early enhancement of the peripheral po rtal branches during the HAP of helical CT, whereas the superior mesenteric and splenic veins remained unenhanced. In five (62.5 %) cases of transient , peripheral, triangular parenchymal enhancement was depicted during the HA P of helical CT; in four of these cases there was associated early of the p ortal branches. Helical CT can show perfusion alterations that might remain undiagnosed with conventional CT. An understanding of the hemodynamic chan ges that occur in APS can help in the interpretation of focal transient hep atic parenchymal enhancement and to differentiate APS from hypervascular tu mors. We believe that the helical CT findings described herein are characte ristic enough to suggest the diagnosis of APS.