MAGNETIC-RESONANCE VELOCITY-MEASUREMENTS IN SMALL ARTERIES - COMPARISON WITH DOPPLER ULTRASONIC MEASUREMENTS IN THE AORTAS OF NORMAL RABBITS

RATIONALE AND OBJECTIVES. Magnetic resonance imaging (MRI) can be used to measure motion. This study compares MRI blood flow velocity measurements to Doppler ultrasound velocity measurements in an animal model. MATERIALS AND METHODS. Blood flow in the abdominal aortas of nine normal rabbits was measured using 16-frame, velocity-resolved MRI and Doppler ultrasound. The MRI data were processed into velocity spectra to aid in their interpretation. RESULTS. Maximum velocity measurements made by rangegated Doppler ultrasound were predicted by the maximum velocity values derived from MR velocity spectra with a slope of 0.861, an intercept of -2.78 cm/second, and an R-value of 0.935 in 70 measurements. CONCLUSIONS. Despite the longer time required for the MR measurement, the MR velocity measurement may be useful in the assessment of deep vessels or those obscured by other structures, which are difficult to measure with ultrasound.