Abstract
Transcutaneous abdominal ultrasound was performed in six adult African Giant Rats (AGR) of both sexes (3 males and 3 females) with mean weight of 825.0 ± 166.0g. Prior to imaging, they were anaesthetized with intra-peritoneal injections of 5mg.kg of 2% Xylazine Hydrochloride and 10mg/kg of 5% Ketamine hydrochloride to facilitate proper restraint. Each rat was examined sonographically using portable ultrasound machine with a 10.0 MHz linear transducer. Measurements such as Dorso-ventral Length of the liver (DVL), Cranio-caudal Length of the liver (CCL), Gall Bladder Long axis (GBLA) and Gall Bladder Short Axis (GBSA) were determined sonographically. Other measurements taken are Stomach Diameter (SD), Stomach Wall Thickness (SWT), Intestinal Wall Thickness (IWT), Right Kidney Long Axis (RKLA), Right Kidney Short Axis (RKSA), Left Kidney Long Axis (LKLA) and Left Kidney Short Axis (LKSA), Uterine Wall Thickness (UWT) and Uterine Diameter (UD). Result showed that the liver of AGR is moderately echogenic and is hypoechoic relatively to the renal capsule. The hepatic vessels appear as anaechoic strands coursing through the liver, while the gall bladder is anaechoic. The stomach is multilayered with the lumen somewhat hyperechoic. The caecum is large and the lumen contains hyperechoic material. Other segments of the intestine were difficult to identify. The kidneys are oval in shape with homogenously gray hyperechoic cortex, while the medulla is hypoechoic. The ovaries of AGR are not visualized with the ultrasound machine. The uterine serosa and endometrium are hyperechoic, the lumen is somewhat hypoechoic. This is the first study describing the sonographic features of major abdominal structures in the AGR. Result of this study can serve as baseline data for further ultrasound studies of the abdomen in domestic and wild rodents

Key words: Abdomen, Ultrasound, African Giant rats, Cricetomys gambianus