A Low-Order Parametric Description of Left Ventricular Kinematics
A Low-Order Parametric Description of Left Ventricular Kinematics
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DOI：
10.1007/s13239-014-0191-9
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发表时间：
2014-12-01
影响因子：
1.8
通讯作者：
Secomb, Timothy W.
中科院分区：
文献类型：
--
作者：
Moulton, Michael J.;Secomb, Timothy W.
左心室（LV）在整个心脏周期的变形的近似描述是在三个时间相关参数的条件下开发的。与舒张末期相对应的参考构型被表示为厚壁长形球体。通过使用长球面坐标，定义了一个三参数的映射族来表示左室壁的变形形状，同时相同地保持壁体积。这三个参数分别代表恒定内体积的伸长、减小内体积的收缩和扭转。利用健康受试者的超声心动图数据说明了其可行性。通过拟合舒张末期长轴图像上左室心内膜和心外膜表面的观测点来定义参考构型。为了与36个左室区域的散斑跟踪超声心动图获得的纵向应变、周向应变和旋转（LS、CS和R）最拟合，获得了定义左室运动学参数的时间序列。比较超声心动图测量的左室基底、中壁和心内膜和心外膜顶点的CS、LS和R。拟合峰值应变与实测值的均方根偏差分别为0.06 （LS）和0.08 （CS）。收缩时左室容积变化的拟合和测量结果非常吻合。在正常和病理心脏中可能很明显的应变的周向变化在这里没有表现出来。结果表明，基于超声心动图数据的左室心肌变形场低阶描述是可行的。这样的描述为LV力学的低阶模型和最终的LV力学参数实时分析提供了基础。
An approximate description for the deformation of the left ventricle (LV) throughout the cardiac cycle is developed in terms of three time-dependent parameters. The reference configuration, corresponding to end-diastole, is represented as a thick-walled prolate spheroid. By using prolate spheroidal coordinates, a three-parameter family of mappings is defined to represent the deformed shapes of the LV wall, while identically conserving wall volume. The three parameters represent lengthening with constant internal volume, contraction with reduction of internal volume, and torsion. Feasibility is illustrated using echocardiography data from a healthy subject. The reference configuration was defined by fitting observed points on LV endocardial and epicardial surfaces in long-axis images at end diastole. Timecourses of parameters defining LV kinematics were obtained for best fit to longitudinal strains, circumferential strains and rotations (LS, CS and R) obtained from speckle tracking echocardiography at 36 LV regions. Fitted versus echocardiography- measured CS, LS and R were compared at the LV base, mid-wall and apex at the endocardium and epicardium. The RMS deviation between fitted and measured peak strains was 0.06 (LS) and 0.08 (CS). Fitted and measured LV volume changes during contraction agreed closely. Circumferential variations in strain, which may be significant in normal and pathological hearts, are not represented here. The results demonstrate feasibility of a low-order description of the deformation field in the LV myocardium, based on echocardiographic imaging data. Such a description provides a basis for low-order models of LV mechanics and eventual real-time patient-specific analysis of LV mechanical parameters.