Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA.
IEEE Trans Med Imaging. 2012 May;31(5):1051-60. doi: 10.1109/TMI.2012.2184799. Epub 2012 Jan 18.
Technological limitations pose a major challenge to acquisition of myocardial fiber orientations for patient-specific modeling of cardiac (dys)function and assessment of therapy. 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.
技术限制对获取心肌纤维方向提出了重大挑战，这对于心脏（功能）障碍的患者特异性建模和治疗评估至关重要。本项目的目的是开发一种从患者心脏几何形状的体内图像估计心脏纤维方向的方法。从正常人心的高分辨率离体结构磁共振（MR）和扩散张量（DT）MR 图像中，分别准确地重建了心室几何形状和纤维方向，这些图像被称为图谱。通过半自动分割，从患者的体内计算机断层扫描（CT）图像中提取患者心脏的心室几何形状。使用图像变换算法，将图谱心室几何形状变形以匹配患者的心室几何形状。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。使用六只正常犬心和三只衰竭犬心评估纤维估计的准确性。获得的和估计的纤维方向的倾斜角之间的平均绝对差异为 15.4°。窦性节律和室性心动过速的心室激活图和伪 ECG 的计算模拟表明，在临床可观察的水平上，估计的纤维方向与获得的纤维方向之间没有显著差异。
