Fast scan magnetic resonance imaging and Doppler ultrasonography of uteroplacental hemodynamics in the rhesus monkey (Macaca mulatta).

Fast scan magnetic resonance imaging, color Doppler ultrasonography, and magnetic resonance angiography were used to demonstrate the uteroplacental hemodynamics in rhesus monkeys. "Jets" of maternal blood spurting into the placenta were observed with, or without, the use of a contrast medium from 114 days to the term of pregnancy. Cumulative intravenous doses of cocaine hydrochloride brought about changes in the sequences of imaging of the maternal blood inflow to the placenta. These methods appear suitable for non-invasive monitoring of the effects of drugs on placental function.