Reyhan Meral, Wang Zhe, Li Ming, Kim Hyun J, Gupta Himanshu, Lloyd Steven G, Dell'Italia Louis J, Denney Thomas, Ennis Daniel B
Biomedical Physics Interdepartmental Program, University of California, Los Angeles, California, USA.
Department of Bioengineering, University of California, Los Angeles, California, USA.
J Magn Reson Imaging. 2015 Aug;42(2):400-6. doi: 10.1002/jmri.24811. Epub 2014 Nov 19.
To evaluate the relationship between left ventricular (LV) twist, shear, and twist-per-volume and the severity of mitral regurgitation (MR). Primary MR is a valvular disorder that induces LV dysfunction. There exist several measures of LV rotational mechanics, but it remains unclear which measure of LV dysfunction best accords with the severity of MR. We hypothesized that LV systolic twist-per-volume slope would decrease with increasing severity of MR because of both decreases in rotational mechanics and increases in stroke volumes.
Normal subjects (n = 54), moderate MR patients (n = 29), and severe MR patients (n = 54) were studied. Magnetic resonance imaging (MRI) was performed on a 1.5T scanner and grid-tagged LV images were collected at the LV base and LV apex. Measures of LV rotational mechanics were derived from tagged images using Fourier Analysis of STimulated echoes (FAST).
Peak systolic twist-per-volume slope was significantly different for all pairwise comparisons (P < 0.0001) and compared to normal subjects (-0.14 ± 0.05°/mL) was decreased in moderate MR (-0.12 ± 0.04°/mL) and further decreased in severe MR (-0.07 ± 0.03°/mL).
Peak systolic twist-per-volume slope significantly decreased with increasing severity of MR and is therefore a suitable quantitative imaging biomarker for LV dysfunction in patients with MR.
评估左心室（LV）扭转、剪切力和单位容积扭转与二尖瓣反流（MR）严重程度之间的关系。原发性MR是一种导致左心室功能障碍的瓣膜疾病。存在多种左心室旋转力学测量方法，但尚不清楚哪种左心室功能障碍测量方法与MR严重程度最相符。我们假设，由于旋转力学下降和每搏量增加，左心室收缩期单位容积扭转斜率会随着MR严重程度的增加而降低。
研究了正常受试者（n = 54）、中度MR患者（n = 29）和重度MR患者（n = 54）。在1.5T扫描仪上进行磁共振成像（MRI），并在左心室基部和左心室尖部采集带网格标记的左心室图像。使用刺激回波的傅里叶分析（FAST）从标记图像中得出左心室旋转力学测量值。
所有两两比较的收缩期峰值单位容积扭转斜率均有显著差异（P < 0.0001），与正常受试者相比（-0.14±0.05°/mL），中度MR患者（-0.12±0.04°/mL）降低，重度MR患者（-0.07±0.03°/mL）进一步降低。
收缩期峰值单位容积扭转斜率随MR严重程度增加而显著降低，因此是MR患者左心室功能障碍的合适定量成像生物标志物。
