Hepatic Arterioportal Shunts: Dynamic CT and MR Features

Abstract

With the increased temporal resolution available in dynamic computed tomography (CT) and magnetic resonance imaging (MRI), hepatic arterioportal shunts are now more frequently encountered than in the past. The condition occurs in various hepatic diseases in which portal or hepatic venous flow is compromised. The underlying mechanism and the degree of shunt affect its appearance at dynamic imaging. The dynamic CT and MRI findings have been summarized as early enhancement of peripheral portal veins, and wedge-shaped transient parenchymal enhancement during the hepatic arterial phase. Recognition of arterioportal shunt can suggest the presence of a previously unsuspected disorder and avoids false-positive diagnosis or overestimation of a hepatic disease. Familiarity with the pathophysiology of arterioportal shunt also allows investigation of the hepatic hemodynamic changes occurring in various hepatic diseases.

Gadoxetic acid‐enhanced MRI versus multiphase multidetector row computed tomography for evaluating the viable tumor of hepatocellular carcinomas treated with image‐guided tumor therapy

“…Hemodynamic alteration, such as microscopic arterioportal shunting around the treated HCC after RFA or TACE, or hypervascular enhancement around RFA representing inflammatory reactions to thermal injury, can occur (22,27). As described in several previous reports (2,3), we believe that this hemodynamic alteration owing to imageguided tumor therapy can resemble or mask HCCs.…”

“…HCCs treated with TACE or RFA have been known to have variable signal intensity on unenhanced T1-and T2-weighted images due to coagulative necrosis and/or iodized oil (15,27,28). Generally, the hypointensity on T2-weighted images is representative of coagulation necrosis.…”

Comparison of long-term effects between intra-arterially delivered ethanol and Gelfoam for the treatment of severe arterioportal shunt in patients with hepatocellular carcinoma

“…In our series, severe APSs were verified in 27% of patients with HCC by DSA. Severe APS leads to or aggravates portal hypertension which leads to life-threatening conditions such as esophageal varices, refractory ascites, refractory diarrhea and hepatic encephalopathy [4][5][6][7]16,17] . Additionally, severe APSs have an influence on the performance of TAI or TACE for the treatment of HCC [18] .…”

“…Kido and Ngan et al [1,2] reported that APS in HCC occurred in 60%, and Okuda et al [3] reported that severe APS of main or right or left portal veins occurred in 30% of patients with HCC. Severe APS led to life threatening conditions (e.g., esophageal varices, ascites and hepatic encephalopathy) as a result of portal regurgitation or portal hypertension [4][5][6][7] . To improve portal hypertension caused by severe APS in patients with HCC, APS needs to be treated.…”

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.…”