Saporito Salvatore, van Assen Hans C, Houthuizen Patrick, Aben Jean-Paul M M, Strik Marc, van Middendorp Lars B, Prinzen Frits W, Mischi Massimo
Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands.
Department of Cardiology, Catharina Hospital Eindhoven, Eindhoven, the Netherlands.
J Magn Reson Imaging. 2016 Oct;44(4):956-63. doi: 10.1002/jmri.25225. Epub 2016 Mar 12.
To compare cine and tagged magnetic resonance imaging (MRI) for left ventricular dyssynchrony assessment in left bundle branch block (LBBB), using the time-to-peak contraction timing, and a novel approach based on cross-correlation.
We evaluated a canine model dataset (n = 10) before (pre-LBBB) and after induction of isolated LBBB (post-LBBB). Multislice short-axis tagged and cine MRI images were acquired using a 1.5 T scanner. We computed contraction time maps by cross-correlation, based on the timing of radial wall motion and of circumferential strain. Finally, we estimated dyssynchrony as the standard deviation of the contraction time over the different regions of the myocardium.
Induction of LBBB resulted in a significant increase in dyssynchrony (cine: 13.0 ± 3.9 msec for pre-LBBB, and 26.4 ± 5.0 msec for post-LBBB, P = 0.005; tagged: 17.1 ± 5.0 msec at for pre-LBBB, and 27.9 ± 9.8 msec for post-LBBB, P = 0.007). Dyssynchrony assessed by cine and tagged MRI were in agreement (r = 0.73, P = 0.0003); differences were in the order of time difference between successive frames of 20 msec (bias: -2.9 msec; limit of agreement: 10.1 msec). Contraction time maps were derived; agreement was found in the contraction patterns derived from cine and tagged MRI (mean difference in contraction time per segment: 3.6 ± 13.7 msec).
This study shows that the proposed method is able to quantify dyssynchrony after induced LBBB in an animal model. Cine-assessed dyssynchrony agreed with tagged-derived dyssynchrony, in terms of magnitude and spatial direction. J. MAGN. RESON. IMAGING 2016;44:956-963.
使用收缩峰值时间以及基于互相关的新方法，比较电影磁共振成像（MRI）和标记磁共振成像在左束支传导阻滞（LBBB）患者左心室不同步评估中的应用。
我们评估了一个犬类模型数据集（n = 10），分别在诱导孤立性LBBB之前（LBBB前）和之后（LBBB后）进行评估。使用1.5T扫描仪采集多层短轴标记和电影MRI图像。我们基于径向壁运动和圆周应变的时间，通过互相关计算收缩时间图。最后，我们将不同步性估计为心肌不同区域收缩时间的标准差。
诱导LBBB导致不同步性显著增加（电影成像：LBBB前为13.0±3.9毫秒，LBBB后为26.4±5.0毫秒，P = 0.005；标记成像：LBBB前为17.1±5.0毫秒，LBBB后为27.9±9.8毫秒，P = 0.007）。电影成像和标记MRI评估的不同步性具有一致性（r = 0.73，P = 0.0003）；差异在连续帧时间差20毫秒的范围内（偏差：-2.9毫秒；一致性界限：10.1毫秒）。得出了收缩时间图；电影成像和标记MRI得出的收缩模式具有一致性（每段收缩时间的平均差异：3.6±13.7毫秒）。
本研究表明，所提出的方法能够在动物模型中量化诱导LBBB后的不同步性。电影成像评估的不同步性在大小和空间方向上与标记成像得出的不同步性一致。《磁共振成像杂志》2016年；44：956 - 963。
