Weiss Kilian, Summermatter Severin, Stoeck Christian T, Kozerke Sebastian
Institute for Biomedical Engineering, University and ETH Zurich, Switzerland; Cardiology Division, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Magn Reson Med. 2014 Nov;72(5):1201-7. doi: 10.1002/mrm.25028. Epub 2013 Nov 20.
To study the influence of cardiac motion on point-resolved single voxel spectroscopy (PRESS) of the human heart and to propose an improved sequence design to compensate for cardiac motion-related signal losses.
Numerical simulations and in vivo measurements were performed to study motion effects in cardiac spectroscopy. Based on the findings, an improved PRESS sequence with reduced free induction decay spoiling areas was implemented. Myocardial triglyceride (TG) content as estimated with the improved PRESS sequence was compared with the default PRESS sequence commonly used for spectroscopy in nonmoving tissues that was provided by the manufacturer.
Numerical simulations and in vivo data show the importance of optimal trigger delays to avoid signal losses in cardiac spectroscopy. The improved PRESS sequence was found to yield a significantly reduced sensitivity to cardiac motion and trigger delay setting and provided a 1.7-fold increase in signal-to-noise ratio on average compared with the default PRESS sequence. Intrasubject variation of myocardial TG content was reduced with the improved sequence compared with the default PRESS sequence (coefficient of variation: 0.11 ± 0.03 versus 0.23 ± 0.06).
Improvement of the sequence design is essential to reduce the sensitivity of PRESS to cardiac motion.
研究心脏运动对人体心脏点分辨单体素磁共振波谱成像（PRESS）的影响，并提出一种改进的序列设计以补偿与心脏运动相关的信号损失。
进行数值模拟和体内测量以研究心脏磁共振波谱成像中的运动效应。基于这些发现，实施了一种具有减少自由感应衰减扰相区域的改进PRESS序列。将使用改进的PRESS序列估计的心肌甘油三酯（TG）含量与制造商提供的常用于非运动组织磁共振波谱成像的默认PRESS序列进行比较。
数值模拟和体内数据表明了最佳触发延迟在避免心脏磁共振波谱成像中信号损失方面的重要性。发现改进的PRESS序列对心脏运动和触发延迟设置的敏感性显著降低，与默认PRESS序列相比，平均信噪比提高了1.7倍。与默认PRESS序列相比，改进序列降低了心肌TG含量的受试者内变异（变异系数：0.11±0.03对0.23±0.06）。
改进序列设计对于降低PRESS对心脏运动的敏感性至关重要。
