Sinusas A J, Papademetris X, Constable R T, Dione D P, Slade M D, Shi P, Duncan J S
Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520-8042, USA.
Am J Physiol Heart Circ Physiol. 2001 Aug;281(2):H698-714. doi: 10.1152/ajpheart.2001.281.2.H698.
A comprehensive three-dimensional (3-D) shape-based approach for quantification of regional myocardial deformations was evaluated in a canine model (n = 8 dogs) with the use of cine magnetic resonance imaging. The shape of the endocardial and epicardial surfaces was used to track the 3-D trajectories of a dense field of points over the cardiac cycle. The shape-based surface displacements are integrated with a continuum biomechanics model incorporating myofiber architecture to estimate both cardiac- and fiber-specific endocardial and epicardial strains and shears for 24 left ventricular regions. Whereas radial and circumferential end-systolic strains were fairly uniform, there was a significant apex-to-base gradient in longitudinal strain and radial-longitudinal shear. We also observed transmural epicardial-to-endocardial gradients in both cardiac- and fiber-specific strains. The increase in endocardial strain was accompanied by increases in radial-longitudinal shear and radial-fiber shears in the endocardium, supporting previous theories of regional myocardial deformation that predict considerable sliding between myocardial fibers.
利用电影磁共振成像技术，在犬类模型（n = 8只犬）中评估了一种基于三维（3-D）形状的区域心肌变形量化综合方法。心内膜和心外膜表面的形状用于跟踪心动周期中密集点场的三维轨迹。基于形状的表面位移与包含肌纤维结构的连续生物力学模型相结合，以估计24个左心室区域的心脏特异性和纤维特异性心内膜及心外膜应变和剪切力。虽然径向和圆周方向的收缩末期应变相当均匀，但纵向应变和径向-纵向剪切力存在显著的从心尖到心底的梯度。我们还观察到心脏特异性和纤维特异性应变在心外膜到心内膜的跨壁梯度。心内膜应变的增加伴随着心内膜中径向-纵向剪切力和径向-纤维剪切力的增加，支持了先前关于区域心肌变形的理论，该理论预测心肌纤维之间会有相当大的滑动。
