Measurement of myocardial mechanics in mice before and after infarction using multislice displacement-encoded MRI with 3D motion encoding
Measurement of myocardial mechanics in mice before and after infarction using multislice displacement-encoded MRI with 3D motion encoding
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DOI：
10.1152/ajpheart.00632.2004
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发表时间：
2005-03-01
影响因子：
4.8
通讯作者：
Epstein, FH
中科院分区：
文献类型：
--
作者：
Gilson, WD;Yang, ZQ;Epstein, FH
心脏MRI是一种准确、无创的评估小鼠心脏结构和功能的方法。除了常规成像外，MRI组织跟踪方法还可以量化心肌力学的许多方面，包括心内位移、应变、扭转和扭转。在本研究中，我们开发并应用了一种基于位移编码成像的新型脉冲序列，该脉冲序列使用受激回波（DENSE）实现了多层覆盖、高空间分辨率和三维位移编码。采用该方法测定C57B1/6小鼠在心肌梗死后1 d及基线时的心肌力学。在基线时，平均收缩跨壁周应变为- 0.14 +/- 0.02，平均收缩径向应变为0.30 +/- 0.05。心包下至心内膜下的周向和径向应变在基线时的变化（P < 0.05）。梗死后1天，梗死心肌和非梗死心肌的三维位移和应变均显著降低。梗死也使归一化收缩扭转从基线值1.35 +/- 0.27度/mm （R = 0.99）降至0.07 +/- 0.54度/mm （R = 0.96, P < 0.05）。高密度磁共振成像（DENSE MRI）可在4.7 T扫描时间< 1 h内评估小鼠心脏的三维心肌力学，可应用于基因工程小鼠心肌力学的研究。
Cardiac MRI is an accurate, noninvasive modality for assessing the structure and function of the murine heart. In addition to conventional imaging, MRI tissue tracking methods can quantify numerous aspects of myocardial mechanics, including intramyocardial displacement, strain, twist, and torsion. In the present study, we developed and applied a novel pulse sequence based on displacement-encoded imaging using stimulated echoes (DENSE) that achieves multislice coverage, high spatial resolution, and three-dimensional (3D) displacement encoding. With the use of this technique, myocardial mechanics of C57B1/6 mice were measured at baseline and 1 day after experimental myocardial infarction. At baseline, the mean systolic transmural circumferential strain was - 0.14 +/- 0.02 and the mean systolic radial strain was 0.30 +/- 0.05. Changes in circumferential and radial strains from the subepicardium to the subendocardium were detected at baseline (P < 0.05). One day after infarction, significantly reduced 3D displacements and strain were detected in infarcted and noninfarcted myocardium. Infarction also reduced normalized systolic torsion from its baseline value of 1.35 +/- 0.27degrees/mm ( R = 0.99) to 0.07 +/- 0.54 degrees/mm (R = 0.96, P < 0.05). DENSE MRI can assess the 3D myocardial mechanics of the murine heart in < 1 h of scan time at 4.7 T and may be applied to studies of myocardial mechanics in genetically engineered mice.