Color Doppler sonography of intrahepatic vascular shunts

The Portal Vein: A Comprehensive Review

Radiologists are familiar with the appearances of a normal portal vein; variations in its anatomy are commonplace and require careful consideration due to the implications for surgery. These alterations in portal vein anatomy have characteristic appearances that are clearly depicted on CT, MR, and US images. Similarly, there are numerous congenital and acquired disorders of the portal vein that are deleterious to its function and can be diagnosed by using imaging alone. Some of these conditions have subtle imaging features, and some are conspicuous at imaging but poorly understood or underrecognized. The authors examine imaging appearances of the portal vein, first by outlining the classic and variant anatomy and then by describing each of the disorders that impact portal vein function. The imaging appearances of portal vein abnormalities discussed in this review include (a) occlusion from and differentiation between bland thrombus and tumor in vein and the changes associated with resultant hepatic artery buffer response changes, cavernous transformation of the portal vein, and portal biliopathy; (b) ascending thrombophlebitis of the portal vein (pylephlebitis); (c) portal hypertension and its causes and sequelae; (d) the newly described disease entity portosinusoidal vascular disorder; and (e) intra- and extrahepatic shunts of the portal system, both congenital and acquired (including Abernethy malformations), and the associated risks. Current understanding of the pathophysiologic processes of each of these disorders is considered to aid the approach to reporting. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Congenital Intrahepatic Portosystemic Venous Shunt With an Associated Aneurysm: Sonographic Diagnosis

Intrahepatic portosystemic venous shunts with associated aneurysms are extremely rare anomalous communications between intrahepatic portal veins and systemic veins through intrahepatic venous channels. Intrahepatic portosystemic venous shunts are usually asymptomatic but can be the cause of hepatic encephalopathy and hypoglycemia, especially when a high degree of shunting exists. The sonographic incidental finding of an aneurysmal vascular connection between the left portal vein and left hepatic vein as diagnosed by sonography is presented and discussed. When evaluating patients with suspected symptoms of hepatobiliary disease, sonographers and radiologists should carefully scan and meticulously assess the liver for signs of abnormal venous communications.

Sonographic classification of draining pathways of obstructed hepatic veins in Budd-Chiari syndrome

PURPOSE

To describe and propose a sonographic classification of the blood-draining pathways of obstructed hepatic veins in Budd-Chiari syndrome.

METHODS

This retrospective study included 206 patients with hepatic vein obstructions who underwent sonographic examination. We evaluated the afflicted hepatic veins, as well as the course, orifice, blood flow direction of draining veins, and communicating branches. Results were classified and compared with digital subtraction angiography and computed tomography angiography.

RESULTS

Of 618 hepatic veins in 206 patients, 542 were obstructed. The blood-draining pathways were classified as hepatic vein-accessory hepatic vein (131/206), hepatic vein-hepatic vein/accessory hepatic+hepatic vein (49/206), and, less frequently, collateral pathways (26/206). Blood was drained from obstructed hepatic veins to the inferior vena cava, right atrium, para-umbilical veins, or hepatic subcapsular veins through communicating branches of various number and diameters. Doppler signals were obtained from the draining veins.

CONCLUSIONS

Sonography provides accurate information regarding the blood-draining pathways of obstructed hepatic veins in Budd-Chiari syndrome, which may be helpful for treatment and follow-up.

Imaging assessment of congenital and acquired abnormalities of the portal venous system

Abnormalities of the portal venous system are a heterogeneous group of conditions that can cause substantial morbidity and mortality and may lead to complications during surgery or percutaneous interventions involving the portal venous system. High-resolution computed tomography, ultrasonography, and magnetic resonance imaging permit a comprehensive, noninvasive evaluation of the portal venous system, enabling the detection of both structural and functional abnormalities. However, an understanding of the embryologic development of the normal portal venous anatomy and anatomic variants is essential to accurately interpret the imaging findings. Knowledge of the characteristic appearances of abnormalities of the portal venous system allows a more confident diagnosis, permitting timely treatment and more informed guidance of surgical procedures and percutaneous interventions, which may lead to an improved outcome.

Pictorial review. Hepatic vascular shunts: embryology and imaging appearances

The purpose of this pictorial review is to understand the embryological basis of the development of congenital hepatic vascular shunts and to review the multimodality imaging appearances of congenital and acquired hepatic vascular shunts. Hepatic vascular shunts are commonly seen in imaging. Familiarity with their characteristic appearances is important in order to accurately characterise these shunts and diagnose the underlying disorders.

Hepatic incidentalomas

Recent advances in multidetector-row computed tomography, magnetic resonance imaging, and ultrasonography have led to the detection of incidental hepatic lesions in both the oncology and nononcology patient population that in the past remained undiscovered. These incidental hepatic lesions have created a management dilemma for both clinicians and radiologists. In this review, guidelines concerning the diagnosis and management of some of the more common hepatic incidentalomas are presented.