OBJECTIVES Diffusion tensor cardiovascular magnetic resonance (DT-CMR) interrogates myocardial microstructure. Two frequently used in vivo DT-CMR techniques are motion-compensated spin echo (M2-SE) and stimulated echo acquisition mode (STEAM). Whilst M2-SE is strain-insensitive and signal to noise ratio efficient, STEAM has a longer diffusion time and motion compensation is unnecessary. Here we compare STEAM and M2-SE DT-CMR in patients. MATERIALS AND METHODS Biphasic DT-CMR using STEAM and M2-SE, late gadolinium imaging and pre/post gadolinium T1-mapping were performed in a mid-ventricular short-axis slice, in ten hypertrophic cardiomyopathy (HCM) patients at 3 T. RESULTS Adequate quality data were obtained from all STEAM, but only 7/10 (systole) and 4/10 (diastole) M2-SE acquisitions. Compared with STEAM, M2-SE yielded higher systolic mean diffusivity (MD) (p = 0.02) and lower fractional anisotropy (FA) (p = 0.02, systole). Compared with segments with neither hypertrophy nor late gadolinium, segments with both had lower systolic FA using M2-SE (p = 0.02) and trend toward higher MD (p = 0.1). The negative correlation between FA and extracellular volume fraction was stronger with STEAM than M2-SE (r2 = 0.29, p < 0.001 STEAM vs. r2 = 0.10, p = 0.003 M2-SE). DISCUSSION In HCM, only STEAM reliably assesses biphasic myocardial microstructure. Higher MD and lower FA from M2-SE reflect the shorter diffusion times. Further work will relate DT-CMR parameters and microstructural changes in disease.

中文翻译：

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肥厚型心肌病的弥散张量心血管磁共振：运动补偿自旋回波和受激回波技术的比较。

目的扩散张量心血管磁共振（DT-CMR）询问心肌的微观结构。体内常用的两种DT-CMR技术是运动补偿自旋回波（M2-SE）和受激回波采集模式（STEAM）。M2-SE对应变不敏感并且信噪比有效，而STEAM的扩散时间更长，因此不需要运动补偿。在这里，我们比较患者的STEAM和M2-SE DT-CMR。材料与方法10例肥厚型心肌病（HCM）患者以3 T的速度在心室中短轴切片上进行了使用STEAM和M2-SE的双相DT-CMR，晚期late成像和pre T1前/后映射。从所有STEAM获得了足够的质量数据，但只有7/10（收缩期）和4/10（舒张期）的M2-SE采集。与STEAM相比，M2-SE产生较高的收缩平均扩散率（MD）（p = 0.02）和较低的分数各向异性（FA）（p = 0.02，收缩期）。与既没有肥大也没有晚期g的节段相比，使用M2-SE均具有较低的收缩期FA的节段（p = 0.02）和趋向于更高的MD的趋势（p = 0.1）。使用STEAM，FA和细胞外体积分数之间的负相关性强于M2-SE（r2 = 0.29，p <0.001 STEAM vs. r2 = 0.10，p = 0.003 M2-SE）。讨论在HCM中，只有STEAM才能可靠地评估双相心肌的微结构。M2-SE的较高MD和较低FA反映了较短的扩散时间。进一步的工作将涉及DT-CMR参数和疾病的微结构变化。使用M2-SE的两个节段的收缩期FA较低（p = 0.02），而MD的趋势则较高（p = 0.1）。使用STEAM，FA和细胞外体积分数之间的负相关性强于M2-SE（r2 = 0.29，p <0.001 STEAM vs. r2 = 0.10，p = 0.003 M2-SE）。讨论在HCM中，只有STEAM才能可靠地评估双相心肌的微结构。M2-SE的较高MD和较低FA反映了较短的扩散时间。进一步的工作将涉及DT-CMR参数和疾病的微结构变化。使用M2-SE的两个节段的收缩期FA较低（p = 0.02），而MD的趋势则较高（p = 0.1）。使用STEAM，FA和细胞外体积分数之间的负相关性强于M2-SE（r2 = 0.29，p <0.001 STEAM vs. r2 = 0.10，p = 0.003 M2-SE）。讨论在HCM中，只有STEAM才能可靠地评估双相心肌的微结构。M2-SE的较高MD和较低FA反映了较短的扩散时间。进一步的工作将涉及DT-CMR参数和疾病的微结构变化。M2-SE的较高MD和较低FA反映了较短的扩散时间。进一步的工作将涉及DT-CMR参数和疾病的微结构变化。M2-SE的较高MD和较低FA反映了较短的扩散时间。进一步的工作将涉及DT-CMR参数和疾病的微结构变化。