Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, United States.
Department of Radiology, Anzhen Hospital, Capital Medical University, Beijing, China.
Sci Rep. 2019 Aug 9;9(1):11563. doi: 10.1038/s41598-019-47869-z.
This study aimed to develop a cardiorespiratory-resolved 3D magnetic resonance imaging (5D MRI: x-y-z-cardiac-respiratory) approach based on 3D motion tracking for investigating the influence of respiration on cardiac ventricular function. A highly-accelerated 2.5-minute sparse MR protocol was developed for a continuous acquisition of cardiac images through multiple cardiac and respiratory cycles. The heart displacement along respiration was extracted using a 3D image deformation algorithm, and this information was used to cluster the acquired data into multiple respiratory phases. The proposed approach was tested in 15 healthy volunteers (7 females). Cardiac function parameters, including the end-systolic volume (ESV), end-diastolic volume (EDV), stroke volume (SV), and ejection fraction (EF), were measured for the left and right ventricle in both end-expiration and end-inspiration. Although with the proposed 5D cardiac MRI, there were no significant differences (p > 0.05, t-test) between end-expiration and end-inspiration measurements of the cardiac function in volunteers, incremental respiratory motion parameters that were derived from 3D motion tracking, such as the depth, expiration and inspiration distribution, correlated (p < 0.05, correlation coefficient, Mann-Whitney) with those volume-based parameters of cardiac function and varied between genders. The obtained initial results suggested that this new approach allows evaluation of cardiac function during specific respiratory phases. Thus, it can enable investigation of effects related to respiratory variability and better assessment of cardiac function for studying respiratory and/or cardiac dysfunction.
本研究旨在开发一种基于三维运动跟踪的心肺分辨三维磁共振成像（5D MRI：x-y-z-心脏-呼吸）方法，以研究呼吸对心室功能的影响。开发了一种高加速的 2.5 分钟稀疏磁共振方案，用于通过多个心脏和呼吸周期连续采集心脏图像。使用三维图像变形算法提取沿呼吸的心脏位移，并使用该信息将采集的数据聚类到多个呼吸相位中。该方法在 15 名健康志愿者（7 名女性）中进行了测试。在呼气末和吸气末分别测量了左心室和右心室的心脏功能参数，包括收缩末期容积（ESV）、舒张末期容积（EDV）、每搏输出量（SV）和射血分数（EF）。尽管使用所提出的 5D 心脏 MRI，志愿者的心脏功能在呼气末和吸气末测量之间没有显著差异（p>0.05，t 检验），但从三维运动跟踪得出的增量呼吸运动参数，例如深度、呼气和吸气分布，与心脏功能的基于体积的参数相关（p<0.05，相关系数，Mann-Whitney），并且在性别之间有所不同。初步结果表明，这种新方法允许在特定呼吸相位评估心脏功能。因此，它可以研究与呼吸变化相关的影响，并更好地评估心脏功能，以研究呼吸和/或心脏功能障碍。
