Intrahepatic arterioportal shunt: helical CT findings

Abstract

The purpose of this study was to characterize the appearance of intrahepatic arterioportal shunts (APS) on two-phase helical CT, with emphasis on the importance of the hepatic arterial-dominant phase (HAP) to demonstrate perfusion disorders. We review eight cases of APS diagnosed by helical CT in our 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 portal branches during the HAP of helical CT, whereas the superior mesenteric and splenic veins remained unenhanced. In five (62.5 %) cases of APS, transient, peripheral, triangular parenchymal enhancement was depicted during the HAP of helical CT; in four of these cases there was associated early enhancement of the portal branches. Helical CT can show perfusion alterations that might remain undiagnosed with conventional CT. An understanding of the hemodynamic changes that occur in APS can help in the interpretation of focal transient hepatic parenchymal enhancement and to differentiate APS from hypervascular tumors. We believe that the helical CT findings described herein are characteristic enough to suggest the diagnosis of APS.

Intrahepatic arterioportal shunting and anomalous venous drainage: understanding the CT features in the liver

“…These potential communications between arteries can be either microscopic or macroscopic and related to trauma such as liver biopsy [2]. APS occur at four levels; transsinusoidal, transtumoral and transplexal shunting contribute arterial blood to the predominantly portal venous blood supply of the venous sinusoid (Fig.…”

“…This perfusion is at pressures of approximately 7 and 100 mmHg, respectively, in the non-cirrhotic patient. Arterioportal parenchymal perfusion can demonstrate a degree of reciprocity of the arterial and portal venous contribution by virtue of vascular flux through dynamic microcirculatory arterioportal shunts (APS), largely at the level of the portal triad [1,2]. These shunts can open up transiently under the influence of angiogenic modulators, but are frequently related to pathology that either compromises portal flow or increases arterial perfusion.…”

Improved Diagnosis of Hepatic Perfusion Disorders: Value of Hepatic Arterial Phase Imaging during Helical CT

“…The helical CT findings of APS are as follows: (a) early enhancement of the peripheral portal vein branches during the HAP and before the main portal vein is enhanced; (b) enhancement of the peripheral portal vein branches and main portal vein without enhancement of the superior mesenteric and splenic veins (3), an appearance that has been considered diagnostic on hepatic angiograms (11,16); and (c) transient, peripheral, wedge-shaped hepatic parenchymal enhancement-usually with a straight margin-during the HAP (THPE) (3,13,17). The last finding usually results from a peripheral APS (15), which manifests as a transient area of high attenuation due to passage of contrast material from highpressure arterial blood into a low-pressure portal vein branch, thus enhancing a focal area of the liver before the adjacent parenchyma is enhanced through the portal venous system (14,17).…”

“…The last finding usually results from a peripheral APS (15), which manifests as a transient area of high attenuation due to passage of contrast material from highpressure arterial blood into a low-pressure portal vein branch, thus enhancing a focal area of the liver before the adjacent parenchyma is enhanced through the portal venous system (14,17).…”

Portal hypertension induced by congenital hepatic arterioportal fistula: Report of four clinical cases and review of the literature

“…In our four cases, ultrasound demonstrated reverse pulsatile flow in the portal vein, thus helping establish the diagnosis. CT and MRI are also helpful for the accurate diagnosis of IAPF [30][31][32] because fistula vessels can be easily identified in the early arterial phase. Contrast-enhanced CT findings of IAPF typically include the following: (1) earlier enhancement of the affected portal vein compared with the superior mesenteric or splenic vein during the arterial phase; and (2) earlier enhancement of the portal vein branches compared with the main portal vein.…”