Ultrasonographic, Radiographic, and CT Features of a Segmental Caudal Vena Cava Aplasia in a Cat

ABSTRACT A 10‐year‐old neutered male domestic shorthair cat presented with acute lethargy, dysorexia, and a single episode of vomiting. Abdominal ultrasound revealed an anomalous and slightly tortuous course of the caudal vena cava (CdVC), just cranial to the junction of the renal veins. Thoracic radiographs showed an abnormally enlarged azygos vein. CT showed the absence of the prehepatic CdVC segment, with postrenal caval blood being shunted to a distended right azygos vein. Segmental CdVC aplasia should be considered in the evaluation of abdominal vascular anomalies in cats, particularly on CT angiography.