Delineation of normal human left ventricular twist throughout systole by tagged cine magnetic resonance imaging
Delineation of normal human left ventricular twist throughout systole by tagged cine magnetic resonance imaging
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DOI：
10.3109/10976640009148678
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发表时间：
2000-01-01
影响因子：
6.4
通讯作者：
Bundy, JM
中科院分区：
文献类型：
--
作者：
Lorenz, CH;Pastorek, JS;Bundy, JM
左心室肌的肌原纤维缩短和斜向纤维取向导致左心室的扭转运动。心脏磁共振成像（MRI）的进步使得有可能无创地标记心肌，并通过心动周期跟踪这种运动（扭转），但关于其完整的收缩时间过程的数据很少。本研究的目的是利用标记的电影MRI描绘正常人心室扭转的收缩时间过程。对10名健康受试者进行了标记电影MRI。计算10名志愿者相对于短轴质心的平均收缩期扭转角。评估研究间、观察者内和观察者间变异性。等容收缩时，心室扭转均为逆时针方向。在收缩后期，右室基底段改变方向，顺时针旋转，而心尖段继续逆时针旋转。旋转中点为心室长度的45 ± 8%。在80%收缩期，平均短净心室扭转（心尖-基底）为12.6 ± 1.5度。四个壁段显示扭曲不均匀性（外侧壁，20.6 +/- 1.7度;前壁，17.5 +/- 5.1度;下壁，8.8 +/- 4.9度;间隔，3.5 +/- 2.4度）。前壁和侧壁的ht isr显著高于其他壁（p < 0.01）。在等容收缩后，扭转在整个收缩期稳定增加，而扭转显示率变化。研究间、观察者内和观察者间的平均差异小于2.1度。受试者之间扭转的密切相似性以及低研究间和观察者间/观察者内变异表明扭转是心肌功能的稳健参数。在收缩期，扭转变化平稳，这可能在最大限度地减少氧气消耗方面发挥作用。这些数据可以作为比较疾病中局部心肌功能改变的基线。
Myofibril shortening and the oblique fiber orientation of the left ventricular myocardium results in a twisting motion of the left ventricle. Advances in cardiac magnetic resonance imaging (MRI) have made it possible to label the myocardium noninvasively and track this motion (twist) through the cardiac cycle, but little data exist on its complete systolic time course. The purpose of this study tvas to delineate the normal human systolic time course of ventricular twist using tagged cine-MRI. Tagged cine-MRI was performed in 10 healthy subjects. The mean systolic twist angle relative to the short axis centroid for the 10 volunteers was calculated. Interstudy and intra- and inter-observer variability were assessed. During isovolumic contraction, all ventricular twist was counter-clockwise. Later in systole, rite basal segments changed direction and rotated in a clockwise direction, whereas the apical segments continued counterclockwise rotation. The midpoint for rotation was 45 +/- 8% of ventricular length. The mean short mis net ventricular twist (apex-base) at 80% systole was 12.6 +/- 1.5 degrees. The four wall segments showed heterogeneity in twist (lateral wall, 20.6 +/- 1.7 degrees; anterior wall, 17.5 +/- 5.1 degrees; inferior wall, 8.8 +/- 4.9 degrees; septum, 3.5 +/- 2.4 degrees). The anterior and lateral walls demonstrated significantly higher ht isr than the other walls (p < 0.01). Torsion increased steadily throughout systole after isovolumic contraction, whereas twist displayed rate changes. The mean interstudy and intra- and interobserver differences were less than 2.1 degrees. The close similarity in twist between subjects and the low interstudy and inter/intraobserver variation indicates that twist is a robust parameter of myocardial function. Torsion varies smoothly during systole, which may play a role in minimizing oxygen consumption. These data cart serve as a baseline from which to compare alterations in regional myocardial function in disease.