Ultrasonic Cardiovascular Measurements in Small Animals

Genetic manipulation is a developing tool in cardiovascular research, and much of this work isdone in mice. Ultrasound equipment designed for use on humans is not suitable for non-invasivemonitoring of cardiovascular parameters in mice due to small organ size (5 mm dia heart) and high heartrates (400-600 bpm). We propose to develop an instrument to measure cardiac output and myocardialfunction non-invasively in mice and other small animals. The goal is to achieve measurementsresolutions on the order of l ms in time, 0.1 mm in cardiac dimensions, and l cm/s in blood flow velocity.A miniature high frequency (20 MHz) ultrasonic transducer and pulsed Doppler instrumentation will bedesigned to measure aortic blood flow velocity and a high resolution M-mode echocardiograph (at 20MHz) will be designed to measure cardiac dimensions and motion. The ultrasonic transmitter-receiverportions of the Doppler/M-mode and real time digital signal processing hardware will be interfaced witha personal computer for display and analysis. The system will be validated using static phantoms andtested on mice. In Phase II we will integrate these parts into a versatile computer-based ultrasonicmeasurement and analysis system for small animals ranging from mice to rabbits.