Abstract
Background:
Ultrasonography (US) is an amply sufficient, definite, and precise method for obtaining objective anatomical data on rabbit kidneys.

Aim:
The aim of the present study was to investigate in vivo the specific ultrasonographic anatomical features of kidneys in New Zealand White rabbits.

Methods:
Ten clinically healthy, sexually mature New Zealand White rabbits, weighing 2.8–3.5 kg, were investigated. The experiment was separated into two parts because the animals were divided into two groups—five males and five females. The male rabbits were studied with a diagnostic ultrasound system (model Vetus 80) equipped with a microconvex multifrequency transducer with a working frequency of 8–10 MHz and a radius of 20 mm, suited for Doppler US. Female animals were investigated with the US device Еsaote MyLabX8Vet and a microconvex multifrequency transducer with working frequency 5 MHz.

Results:
The in vivo longitudinal US anatomical scanning of the right kidney showed the anatomical contact of the organ with the caudate process of the liver, descending part of the duodenum, and the ascending colon. Within the renal medulla, five to eight hypoechoic renal pyramids with indistinct ends, terminating in the sharply delineated hyperechoic renal papilla, were observed. The longitudinal US imaging of the left kidney provided data about the organ’s multipyramidal features. The renal pyramids were five to eight, of hypoechoic profile, and terminated in the hyperechoic renal papilla and the adjacent renal crest. The color Doppler imaging of the right kidney identified two arterial branches—a dorsal primary and a ventral primary branch. The color Doppler mode of the left renal artery and its dorsal primary branch depicted a flow direction travelling away from the transducer of dark blue color. The interlobar arteries were visible in the vicinity of the renal pyramids.

Conclusion:
The data from the present investigation suggest a new aspect for the anatomy of the rabbit kidneys. These organs are multipyramidal organs, composed of renal pyramids, whose ends fuse in one renal papilla. The color Doppler provides the right and the left renal artery and their division into dorsal and ventral primary branches.

Key words: Doppler ultrasonography; Morphometry; Renal anatomy; Ultrasonography.