Chatzimavroudis G P, Oshinski J N, Franch R H, Walker P G, Yoganathan A P, Pettigrew R I
Department of Chemical Engineering, Cleveland State University, Ohio, USA.
J Cardiovasc Magn Reson. 2001;3(1):11-9. doi: 10.1081/jcmr-100000142.
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 of ten subjects, seven of which had 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 flow 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-Altman 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 blood flow 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 blood flow.
由于缺乏经过验证的临床血流定量技术，评估磁共振相速度映射（PVM）的体内准确性并非易事。本研究的目的是通过在1.5特斯拉扫描仪中研究其体外和体内的精度来评估PVM。在前一种情况下，使用主动脉模型在各种血流条件下进行稳定和搏动血流实验（稳定：0.1 - 5.5升/分钟；搏动：10 - 75毫升/周期）。在后一种情况下，对10名受试者的升主动脉进行PVM测量，其中7名患有主动脉瓣反流。每次速度测量进行两次，切片垂直于主动脉的长轴。测量的和真实的流速及流量之间的比较证实了PVM在体外测量血流方面的高精度（p > 0.85）。发现PVM的体外精度非常高（稳定：y = 1.00x + 0.02，r = 0.999；搏动：y = 0.98x + 0.72，r = 0.997；x：测量值#1，y：测量值#2），这通过布兰德 - 奥特曼分析得到了证实。具有重大临床意义的是体内精度水平很高（y = 1.01x - 0.04，r = 0.993），经统计学证实（p = 1.00）。总之，PVM提供了可重复的血流测量。高体外准确性和精度，再加上高体内精度，是将PVM确立为血流定量“金标准”的关键因素。
