Variations in blood flow waveforms in stenotic renal arteries by 2D phase-contrast cine MRI

Waveform variations in blood now measurements through stenotic renal arteri es have been reported already with echo Doppler studies. We studied these v ariations with MRI in 14 patients (mean age, 60 years) with suspected renal arterial stenosis (24 patent arteries, four occluded). Flow measurements w ere successful in 15 arteries and unsuccessful in nine, due to practical li mitations. Seven healthy younger volunteers (mean age, 28 years) and five h ealthy older volunteers (mean age, 58 years) were recruited for comparison purposes. In patients, the severity of stenoses was also assessed by digita l subtraction angiography and intraarterially measured transstenotic pressu re drops. We found now patterns to be statistically significantly (P < 0.01 ) age-related. Younger healthy subjects showed shorter wave duration, highe r diastolic now. and total blood now per minute. Also, with increasing sten osis severity, the systolic wave became more damped and the systolic wave d uration became statistically significantly (P = .03) longer.