Vadakkumpadan Fijoy, Arevalo Hermenegild, Trayanova Natalia A
Institute for Computational Medicine and the Department of Biomedical Engineering, Johns Hopkins University, USA.
J Vis Exp. 2013 Jan 8(71):50125. doi: 10.3791/50125.
Patient-specific simulations of heart (dys)function aimed at personalizing cardiac therapy are hampered by the absence of in vivo imaging technology for clinically acquiring myocardial fiber orientations. The objective of this project was to develop a methodology to estimate cardiac fiber orientations from in vivo images of patient heart geometries. An accurate representation of ventricular geometry and fiber orientations was reconstructed, respectively, from high-resolution ex vivo structural magnetic resonance (MR) and diffusion tensor (DT) MR images of a normal human heart, referred to as the atlas. Ventricular geometry of a patient heart was extracted, via semiautomatic segmentation, from an in vivo computed tomography (CT) image. Using image transformation algorithms, the atlas ventricular geometry was deformed to match that of the patient. Finally, the deformation field was applied to the atlas fiber orientations to obtain an estimate of patient fiber orientations. The accuracy of the fiber estimates was assessed using six normal and three failing canine hearts. The mean absolute difference between inclination angles of acquired and estimated fiber orientations was 15.4 °. Computational simulations of ventricular activation maps and pseudo-ECGs in sinus rhythm and ventricular tachycardia indicated that there are no significant differences between estimated and acquired fiber orientations at a clinically observable level.The new insights obtained from the project will pave the way for the development of patient-specific models of the heart that can aid physicians in personalized diagnosis and decisions regarding electrophysiological interventions.
旨在实现心脏治疗个性化的患者特异性心脏（功能失调）功能模拟，因缺乏用于临床获取心肌纤维方向的体内成像技术而受到阻碍。本项目的目标是开发一种从患者心脏几何结构的体内图像估计心脏纤维方向的方法。分别从一个正常人类心脏的高分辨率离体结构磁共振（MR）和扩散张量（DT）MR图像（称为图谱）重建了心室几何结构和纤维方向的精确表示。通过半自动分割从体内计算机断层扫描（CT）图像中提取患者心脏的心室几何结构。使用图像变换算法，将图谱心室几何结构变形以匹配患者的结构。最后，将变形场应用于图谱纤维方向以获得患者纤维方向的估计值。使用六个正常犬心脏和三个衰竭犬心脏评估了纤维估计的准确性。获取的和估计的纤维方向倾斜角之间的平均绝对差值为15.4°。窦性心律和室性心动过速时心室激活图和伪心电图的计算模拟表明，在临床可观察水平上，估计的和获取的纤维方向之间没有显著差异。该项目获得的新见解将为开发患者特异性心脏模型铺平道路，这些模型可帮助医生进行个性化诊断以及有关电生理干预的决策。
