Gorodisky Lior, Agmon Yoram, Porat Moshe, Abadi Sobhi, Lessick Jonathan
Department of Electrical Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
Cardiology Department, Rambam Health Care Campus, Haaliya Street, 31096, Haifa, Israel.
Int J Cardiovasc Imaging. 2018 May;34(5):793-802. doi: 10.1007/s10554-017-1290-0. Epub 2017 Dec 19.
To test the feasibility of assessing mitral regurgitation (MR) severity using cardiac magnetic resonance (CMR) 4D velocity vectors to quantify regurgitant volume (RVol) by analysis of the proximal flow convergence, compared to Doppler based proximal isovelocity surface area (PISA) and CMR volume-based methods. In a prospectively designed study, 27 patients with various grades of MR underwent CMR and echo-Doppler on the same day. By CMR, multiple slices were obtained parallel to the mitral valve by phase-contrast imaging, using 3D velocity vectors, as well as short-axis cine images for left and right ventricular volume measurements. Using dedicated software developed in our laboratory, the perimeter of the proximal flow convergence region was semi-automatically measured for each temporal phase, and for each short-axis slice. The CMR-PISA RVol was calculated as the sum of PISA perimeters throughout systole, multiplied by slice width. For comparison, CMR-volumetric RVol was calculated by 2 methods: Volumetric (difference between left and right ventricular stroke volumes) and Flow-based (stroke volume -aortic flow). Echo-PISA RVol was calculated by echo-Doppler based PISA method. RVol by CMR-PISA correlated highly with echo-PISA (r = 0.87) and with CMR-volumetric (r = 0.86) and CMR-flow (r = 0.72). For comparison Doppler-RVol and CMR-volume-based RVol had r = 0.83. On average CMR-PISA was 16 ± 25 ml less than echo-PISA, but 12 ± 22 ml larger than CMR-volumetric RVol. The observed 3D shape of the PISA envelope by 4D-CMR resembled a hemiellipsoid rather than a hemisphere. This feasibility study suggests that CMR-based 4D-PISA may be able to assess MR severity quantitatively without any geometric assumptions.
为了测试使用心脏磁共振成像（CMR）4D速度矢量通过分析近端血流汇聚来量化反流容积（RVol）以评估二尖瓣反流（MR）严重程度的可行性，并与基于多普勒的近端等速表面积（PISA）法和基于CMR容积的方法进行比较。在一项前瞻性设计的研究中，27例不同程度MR患者于同一天接受了CMR和超声多普勒检查。通过CMR，利用3D速度矢量通过相位对比成像获得平行于二尖瓣的多个层面图像，以及用于测量左、右心室容积的短轴电影图像。使用我们实验室开发的专用软件，对每个时间相位和每个短轴层面半自动测量近端血流汇聚区域的周长。CMR-PISA法计算的RVol为整个收缩期PISA周长之和乘以层面厚度。为作比较，CMR容积法计算的RVol采用两种方法：容积法（左、右心室每搏量之差）和基于流量法（每搏量-主动脉流量）。超声-PISA法计算的RVol采用基于超声多普勒的PISA法。CMR-PISA法计算的RVol与超声-PISA法（r = 0.87）、CMR容积法（r = 0.86）和CMR流量法（r = 0.72）高度相关。作比较，多普勒-RVol与基于CMR容积法的RVol的相关性为r = 0.83。平均而言，CMR-PISA法计算的RVol比超声-PISA法少16±25 ml，但比CMR容积法计算的RVol多12±22 ml。4D-CMR观察到的PISA包络的3D形状类似半椭球体而非半球体。这项可行性研究表明，基于CMR的4D-PISA法或许能够在无需任何几何假设的情况下定量评估MR严重程度。
