Page 6 - Clinical Connections- Summer 2021
P. 6

RVC RESEARCH    STUDY    VETERINARY SERVICES       RVC.AC.UK
         Clinical Research

        DIAGNOSTIC IMAGING OF PORTOSYSTEMIC
        SHUNTS


        Mark Plested, Staff Clinician in Veterinary Diagnostic Imaging, and Randi Drees, Associate Professor in
        Veterinary Diagnostic Imaging
             he imaging of portosystemic    allows an excellent overview of the   Over the past few years, the diagnostic
             shunts is a hot topic in the world   anatomy.                      imaging team at the Queen Mother
        T of veterinary radiology, with a     Accurately determining the morphology   Hospital for Animals (QMHA) set out to
        large number of research articles being   of portosystemic shunts, including their   further characterise the morphology of
        published on the subject in the last 10   origin and insertion, is important for   intrahepatic portosystemic shunts – a
        years. Following a gradual transition from   preoperative planning and minimising   rarer form of shunt that typically occurs
        ultrasound to CT as the diagnostic test of   surgical times in these patients. The   in large breed dogs. Intrahepatic shunts
        choice, the variations and complexities   majority of research so far has focused   are challenging to diagnose and fully
        of portosystemic shunts have become   on the classification of extrahepatic   assess using ultrasonography, due to the
        increasingly clear. CT images can provide   portosystemic shunts – those anomalous   complex anatomy of the portal veins and
        a highly detailed assessment of the   connections between the portal vein and   the systemic hepatic veins within the liver.
        abdominal vasculature, and the ability   the systemic circulation that occur most   No comprehensive assessment of the
        to reconstruct images in multiple planes   commonly in small breed dogs.  appearance of intrahepatic shunts in CT


























































         Figure 1: The newly introduced classification system for intrahepatic portosystemic shunts determines the shunt type based on the insertion of the
         abnormal connection via an existing hepatic vein. These schematic drawings and corresponding CT angiography images show examples of subtypes
         for single right divisional intrahepatic shunts: connecting to the systemic venous circulation via the right lateral (A, B) and caudate (C, D) hepatic vein
         respectively.

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