Morphologic and Doppler Findings from Hepatic Ultrasonography of Normal Cynomolgus Monkeys (Macaca fascicularis).

The present study evaluated the anatomic and ultrasonographic features of the liver in normal cynomolgus monkeys (Macaca fascicularis). Healthy, male, cynomolgus monkeys from Cambodia (n = 25; mean age, 58.1 mo) were sedated with ketamine (7 mg/kg) and examined by using 2D and Doppler ultrasonography. We measured the diameters of the vascular structures and bile duct, determined the velocities of the hepatic artery and portal vein, and calculated the resistance index of the hepatic artery. Vessel diameters were: proper hepatic artery, 1.4 mm (range, 1.0-1.9 mm); main portal vein, 4.4 mm (range, 2.4-6.0 mm); and common bile duct, 1.5 mm (range, 1.0-2.4 mm). The mean peak systolic velocity of the proper hepatic artery was 75.4 cm/s, and the resistance index was 0.54. The mean velocity of the main portal vein was 19.3 cm/s. All Doppler ultrasonographic findings, including the peak systolic velocity, end-diastolic velocity, and resistance index of the proper hepatic artery and the main portal vein velocity were independent of body weight. These findings have the potential to serve as references for determining the health status of the liver from cynomolgus monkeys.