Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Three The Abd omen 311
Fig. 3-74 Longitudinal sonograms
of the cranial abdomen of a 10-
month-old male Yorkshire Terrier
with a history of stunted growth,
dementia, and elevated liver enzyme
values. There is a large vessel (small
white arrows) originating from the
portal vein (PV) that communicated
with the caudal vena cava (CVC).
This is indicative of an extrahepatic
portacaval shunt. Diagnosis:
Extrahepatic portacaval shunt.
Fig. 3-75 Longitudinal sonograms
of the liver of a 5-year-old male
mixed breed dog with a history of
respiratory distress of 3 weeks duration.
There is marked hepatic venous
distention. This is indicative of
venous obstruction, which may be
associated with an intrathoracic
(cardiac or caudal mediastinal)
mass, pericardial disease, or right
heart failure. Diagnosis: Right heart
failure secondary to heartworms.
Arteriovenous Fistula. Ultrasonography has been used to document arteriovenous fistula
in dogs. Anechoic, irregular, tortuous tubular structures were identified adjacent to or
within the liver. Depending upon where these are in the liver, they may be confused with
dilated intrahepatic bile ducts except for the blood flow, which can be identified with some
forms of Doppler imaging. 318-321 Doppler examination will usually demonstrate unidirectional,
continuous, and usually pulsatile flow within these structures. 318