Imaging of experimental venous thrombus by means of Doppler and CEUS techniques in dogs

Venous thrombosis has been widely studied in humans, but not in dogs. This study was designed to evaluate a venous thrombus in dogs, from creation to solution, by means of various ultrasonographic techniques. Nine healthy Beagle dogs were included in the study. The venous thrombus was formatted by puncturing the lumen of the external jugular veins and then, the veins were examined with B-mode, color Doppler, pulsed-wave Doppler, and contrast-enhanced ultrasound (CEUS) techniques, at regular intervals, within 210-270 min after venipuncture. Haemodynamic parameters were calculated at two different locations, before and after the site of the thrombus formation. The existence of a thrombus was confirmed by CEUS technique. Thrombus volume and echogenicity were evaluated. The results showed that the visualization of the venous thrombus by color Doppler modality was not feasible in some veins. The blood volume was the parameter that could more precisely indicate the presence or absence of a thrombus. In cases where thrombus volume was less than 0.001 cm³, it was impossible to detect its presence using haemodynamic parameters. The CEUS imaging depicted accurately the size and shape of an anechoic venous thrombus, even when its volume was 0.001cm³.