CT variants of the caudal vena cava in 121 small breed dogs

Abstract

Computed tomography is increasingly used as a treatment planning method in canine patients with diseases of the retroperitoneum, however, published information on normal variations in the caudal vena cava (CVC) are currently lacking. The objectives of this retrospective descriptive study were to characterize CVC variants using CT angiography in a sample of small breed dogs and localize the CVC bifurcations for each variant. Inclusion criteria were small breed dogs (weight ≤ 15) that underwent contrast‐enhanced CT scans of the CVC, abdominal aorta, and CVC tributaries. A total of 121 small breed dogs were sampled. Four right‐sided and one left‐sided CVC variations were identified: normal (88/121, 72.7%), caudal‐partial split (17/121, 14.0%), partial duplication (8/121, 6.6%), complete duplication (7/121, 5.8%), and left‐sidedness (1/121, 0.8%). The mean lumbar vertebral levels of the CVC bifurcation were L6.39 ± 0.41, L5.70 ± 0.35, L4.39 ± 0.42, L2.74 ± 0.38, and L6.4 in the normal, caudal‐partial split, partial duplication, complete duplication, and left‐sidedness types, respectively. The location of the CVC bifurcation, the relationship between the aortic trifurcation and the CVC bifurcation, and the location of the bilateral deep circumflex iliac veins with respect to the CVC bifurcation were significantly different among the right‐sided types (P ≤ .001). Bilateral deep circumflex iliac veins joined to the ipsilateral common iliac veins and the CVC in the caudal‐partial split and duplication types, respectively. The results of this study indicated that canine CVC variants may be frequent and should be considered during surgery or diagnostic imaging of the retroperitoneum.

Computed tomographic appearance of transcaval ureter in two dogs and three cats: A novel CVC congenital malformation

“…In human and veterinary medicine, congenital anomalies of the IVC/CVC are increasingly recognized in asymptomatic patients due to the increased use of cross-sectional imaging technique such as CT, offering simultaneous evaluation of the vascular system and urinary tract with the aid of uroangiographic ICM ( 30 ). Although the anomalies of the vessels and ureters are often clinically silent, it is important to recognize them in order to avoid potential complication during surgery and interventional radiology procedures ( 31 ).…”

“…The association of congenital anomalies of the IVC/CVC with other malformations is reported in both human and veterinary medicine, but the incidence is still unclear because these anomalies might be often underdiagnosed. Small-breed dogs was reported that 7% of patients with malformation of CVC might present with a concomitant extrahepatic portosystemic shunt, while a left-sided circumcaval ureter was reported in association with the transposition of the CVC ( 5 , 30 , 32 ). In the present case series, the only concomitant congenital anomaly found was duplication of the spleen in one patient; however, for the authors knowledge, this anomaly has never previously been associated with IVC/CVC malformations ( 37 ).…”

“…The second type consisted of a double-barrel gun sign with asymmetrical vascular branches, located right dorsal to the aorta. Previous studies have reported that asymmetry of venous diameters in cases of CVC duplication is secondary to a regression disorder of the supracardinal vein, which may be located dorsolaterally to the aorta in the caudal portion of the prerenal segment ( 30 , 32 ). Despite this theory was formulated for the duplication of IVC/CVC, the authors speculate that similar embryogenetic processes may also be involved in generating this particular pattern of congenital malformation.…”

Computed tomographic reference ranges of intrathoracic caudal vena cava ratios in sedated adult dogs without cardiac, pulmonary, or hypovolemic disease

“…The multitude of possible thoracic conformations and sizes among the canine population prohibits the use of an absolute CVC size measurement, and there can be wide variability in margin definition of the CVC which may create measurement error. Recent investigations have reported characteristics of anatomic CVC variations within the canine population (Bertolini et al., 2014 ; Choi et al., 2016 ; Ryu et al., 2019 ; Schwarz et al., 2009 ; Specchi et al., 2014 ). As a result, assessment of the intrathoracic CVC is often challenging, particularly for practitioners with less experience in evaluating thoracic radiographs and non‐imaging specialists.…”

Anatomical Characteristics of Duplicated Caudal Vena Cava in Cats—A Case Report

“…The CVC terminates dorso-caudally in the right cardiac atrium [8]. Based on the results of retrospective veterinary studies on domestic animals, many CVC variants have been described [9], and their presence significantly increases the risk of accompanying ureteric anomalies or portosystemic shunts (Table 1). In the case that the collateral system provides an adequate venous return, most congenital venous anomalies, including duplicated CVC (dCVC), remain silent and asymptomatic [4,10,11].…”