Evaluation of the precision of magnetic resonance phase velocity mapping for blood flow measurements

Evaluating the in vivo accuracy of magnetic resonance phase velocity. mapping (PVM) is not straightforward because of the absence of a validated clinical flow quantification technique. The aim of this study was to evaluate PVM by investigating its precision, both in vitro and in vivo, in a 1.5 Tesla scanner In the former case, steady and pulsatile flow experiments were conducted using an aortic model under a variety of flow conditions (steady : 0.1-5.5 L/min, pulsatile. 10-75 mL/cycle). In the latter case, PVM measurements were taken in the ascending aorta often subjects, seven of which hem aortic regurgitation. Each velocity measurement was taken twice, with the slice perpendicular to the long axis of the aorta. Comparison between, the measured and true flow rates and volumes confirmed the high accuracy of PVM in measuring pou in vitro (p > 0.85). The in vitro precision of PVM was found to be very high (steady: y = 1.00x + 0.02. r = 0.999: pulsatile: y = 0.98x + 0.72. r = 0.997: x: measurement #1, y : measurement #2) and this was confirmed by Bland-Airman analysis. Of great clinical significance was the high level of the in vivo precision (y = 1.01x - 0.04. r = 0.993), confirmed statistically (p = 1.00). In conclusion. PVM provides repeatable bloodflow measurements. The high in vitro accuracy and precision, combined with the high in vivo precision, are key factors for the establishment of PVM as the gold-standard to quantify bloodflow.