Prosthetic heart valve evaluation by magnetic resonance imaging
Prosthetic heart valve evaluation by magnetic resonance imaging
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DOI：
10.1016/s1010-7940(99)00215-8
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发表时间：
1999-09-01
影响因子：
3.4
通讯作者：
Pedersen, EM
中科院分区：
文献类型：
--
作者：
Hasenkam, JM;Ringgaard, S;Pedersen, EM
目的：评价磁共振成像（MRI）评价人工主动脉瓣下游速度场的潜力。此外，提供体外和患者双叶主动脉瓣假体的比较数据。研究方法：在7.0 T MRI扫描仪中设置脉动流回路，以研究25 mm主动脉双叶人工心脏瓣膜下游的流体速度数据。显示了速度场的三维表面图。在6名NYHA I级患者中，使用1.5 T MRI全身扫描仪研究了St. Jude Medical主动脉瓣下游的血流速度曲线。血流速度数据显示如上所述。结果如下：从瓣膜下游0.25瓣膜直径的体外研究中获得的流体速度曲线显示了流体速度横截面分布的重要细节。这种分布完全反映了瓣膜设计。人类的血流速度曲线相当平滑，在某些情况下，最高速度偏向右前升主动脉壁。结论：使用MRI技术显示和解释人工瓣膜下游获得的流体和血液速度数据在体外和体内都是可行的。具有直管和与试管长轴垂直取向的测试瓣膜的体外模型不需要与从人类获得的流体速度曲线兼容的流体速度曲线，这可能是由于人体几何形状复杂得多，以及瓣膜的可变对准。与升主动脉。随着MRI扫描仪质量的稳步提高，该技术在比较心脏瓣膜的体外和体内血流动力学评价方面具有重要的潜力。(C)1999 Elsevier Science B.V.保留所有权利。
Objective: To evaluate the potential of magnetic resonance imaging (MRI) for evaluation of velocity fields downstream of prosthetic aortic valves. Furthermore, to provide comparative data from bileaflet aortic valve prostheses in vitro and in patients. Methods: A pulsatile flow loop was set up in a 7.0 Tesla MRI scanner to study fluid velocity data downstream of a 25 mm aortic bileaflet heart valve prosthesis. Three dimensional surface plots of velocity fields were displayed. In six NYHA class I patients blood velocity profiles were studied downstream of their St. Jude Medical aortic valves using a 1.5 Tesla MRI whole-body scanner. Blood velocity data were displayed as mentioned above. Results: Fluid velocity profiles obtained from in vitro studies 0.25 valve diameter downstream of the valve exhibited significant details about the cross sectional distribution of fluid velocities. This distribution completely reflected the valve design. Blood velocity profiles in humans were considerably smoother and in some cases skewed with the highest velocities toward the anterior-right ascending aortic wall. Conclusion: Display and interpretation of fluid and blood velocity data obtained downstream of prosthetic valves is feasible both in vitro and in vivo using the MRI technique. An in vitro model with a straight tube and the test valve oriented orthogonally to the long axis of the test tube does not entail fluid velocity profiles which are compatible to those obtained from humans, probably due to the much more complex human geometry, and variable alignment of the valve with the ascending aorta. With the steadily improving quality of MRI scanners this technique has significant potential for comparative in vitro and in vivo hemodynamic evaluation of heart valves. (C) 1999 Elsevier Science B.V. All rights reserved.