SLICE LOCATION DEPENDENCE OF AORTIC REGURGITATION MEASUREMENTS WITH MR PHASE-VELOCITY MAPPING

Although several methods have been used clinically to assess aortic re gurgitation (AR), there is no ''gold standard'' for regurgitant volume measurement, Magnetic resonance phase velocity mapping (PVM) can be u sed for noninvasive blood flow measurements, To evaluate the accuracy of PVM in quantifying AR with a single imaging slice in the ascending aorta, in vitro experiments were performed by using a compliant aortic model, Attention was focused on determining the slice location that p rovided the best results, The most accurate measurements were taken be tween the aortic valve annulus and the coronary ostia where the measur ed (Y) and actual (X) flow rate had close agreement (Y = 0.954 x + 0.1 26, r(2) = 0.995, standard deviation of error = 0.139 L/min), Beyond t he coronary ostia, coronary flow and aortic compliance negatively affe cted the accuracy of the measurements, In vivo measurements taken on p atients with AR showed the same tendency with the in vitro results, In making decisions regarding patient treatment, diagnostic accuracy is very important, The results from this study suggest that higher accura cy is achieved by placing the slice between the aortic valve and the c oronary ostia and that this is the region where attention should be fo cused for further clinical investigation.