PURPOSE We exploited 4-dimensional flow magnetic resonance imaging (4D Flow), combined with a standardized in vitro setting, to establish a comprehensive benchmark for the systematic hemodynamic comparison of surgical aortic bioprosthetic valves (BPVs). MATERIALS AND METHODS 4D Flow analysis was performed on two small sizes of three commercialized pericardial BPVs (Trifecta™ GT, Carpentier-Edwards PERIMOUNT Magna and Crown PRT®). Each BPV was tested over a clinically pertinent range of continuous flow rates within an in vitro MRI-compatible system, equipped with pressure transducers. In-house 4D Flow post-processing of the post-valvular velocity field included the quantification of BPV effective orifice area (EOA), transvalvular pressure gradients (TPG), kinetic energy and viscous energy dissipation. RESULTS The 4D Flow technique effectively captured the 3-dimensional flow pattern of each device. Trifecta exhibited the lowest range of velocity and kinetic energy, maximized EOA (p < 0.0001) and minimized TPGs (p ≤ 0.015) if compared with Magna and Crown, these reporting minor EOA difference s (p ≥ 0.042) and similar TPGs (p ≥ 0.25). 4D Flow TPGs estimations strongly correlated against ground-truth data from pressure transducers; viscous energy dissipation proved to be inversely proportional to the fluid jet penetration. CONCLUSION The proposed 4D Flow analysis pinpointed consistent hemodynamic differences among BPVs, highlighting the not negligible effect of device size on the fluidynamic outcomes. The efficacy of non-invasive 4D Flow MRI protocol could shed light on how standardize the comparison among devices in relation to their actual hemodynamic performances and improve current criteria for their selection.

中文翻译：

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外科生物瓣膜的4D Flow MRI血流动力学基准测试。

目的我们利用4维流式磁共振成像（4D Flow），结合标准化的体外设置，为外科主动脉生物瓣膜（BPV）的系统血流动力学比较建立了综合基准。材料与方法对两种小尺寸的三种商品化心包BPV（Trifecta™GT，Carpentier-Edwards PERIMOUNT Magna和CrownPRT®）进行4D流动分析。在配有压力传感器的体外MRI兼容系统中，在临床相关的连续流速范围内对每个BPV进行了测试。瓣膜后速度场的内部4D流后处理包括BPV有效孔口面积（EOA），跨瓣压力梯度（TPG），动能和粘性能量耗散的量化。结果4D流技术有效地捕获了每个设备的3D流模式。与麦格纳和克朗相比，Trifecta展示出最低的速度和动能范围，最大EOA（p <0.0001）和最小化TPG（p≤0.015），这些都报告较小的EOA差s（p≥0.042）和相似的TPG（p≥ 0.25）。4D Flow TPGs估算值与压力传感器的真实数据高度相关；粘性能量耗散与流体射流的渗透率成反比。结论拟议的4D流分析可准确指出BPV之间的一致血流动力学差异，强调了装置尺寸对流体动力学结果的不可忽略的影响。