Department of Biomedical Engineering, University of Virginia Health System, Charlottesville, Virginia.
Department of Medicine, Cardiovascular Division, University of Virginia Health System, Charlottesville, Virginia.
Magn Reson Med. 2019 Aug;82(2):706-720. doi: 10.1002/mrm.27763. Epub 2019 Apr 21.
To develop a continuous-acquisition cardiac self-gated spiral pulse sequence and a respiratory motion-compensated reconstruction strategy for free-breathing cine imaging.
Cine data were acquired continuously on a 3T scanner for 8 seconds per slice without ECG gating or breath-holding, using a golden-angle gradient echo spiral pulse sequence. Cardiac motion information was extracted by applying principal component analysis on the gridded 8 × 8 k-space center data. Respiratory motion was corrected by rigid registration on each heartbeat. Images were reconstructed using a low-rank and sparse (L+S) technique. This strategy was evaluated in 37 healthy subjects and 8 subjects undergoing clinical cardiac MR studies. Image quality was scored (1-5 scale) in a blinded fashion by 2 experienced cardiologists. In 13 subjects with whole-heart coverage, left ventricular ejection fraction (LVEF) from SPiral Acquisition with Respiratory correction and Cardiac Self-gating (SPARCS) was compared to that from a standard ECG-gated breath-hold balanced steady-state free precession (bSSFP) cine sequence.
The self-gated signal was successfully extracted in all cases and demonstrated close agreement with the acquired ECG signal (mean bias, -0.22 ms). The mean image score across all subjects was 4.0 for reconstruction using the L+S model. There was good agreement between the LVEF derived from SPARCS and the gold-standard bSSFP technique.
SPARCS successfully images cardiac function without the need for ECG gating or breath-holding. With an 8-second data acquisition per slice, whole-heart cine images with clinically acceptable spatial and temporal resolution and image quality can be acquired in <90 seconds of free-breathing acquisition.
开发一种连续采集的心脏自门控螺旋脉冲序列和一种呼吸运动补偿重建策略，用于自由呼吸电影成像。
在 3T 扫描仪上连续采集电影数据，每片 8 秒，无需心电图门控或屏气，使用黄金角度梯度回波螺旋脉冲序列。通过对网格化的 8×8 k 空间中心数据应用主成分分析，提取心脏运动信息。通过在每个心跳上进行刚性配准来校正呼吸运动。使用低秩稀疏（L+S）技术重建图像。该策略在 37 名健康受试者和 8 名接受临床心脏磁共振研究的受试者中进行了评估。由 2 名有经验的心脏病专家以盲法对图像质量进行评分（1-5 分）。在 13 名具有全心脏覆盖的受试者中，SPiral Acquisition with Respiratory correction and Cardiac Self-gating（SPARCS）的左心室射血分数（LVEF）与标准心电图门控屏气平衡稳态自由进动（bSSFP）电影序列进行了比较。
在所有情况下都成功提取了自门控信号，并且与采集的心电图信号具有很好的一致性（平均偏差，-0.22ms）。所有受试者的平均图像评分在使用 L+S 模型重建时为 4.0。SPARCS 得出的 LVEF 与金标准 bSSFP 技术具有良好的一致性。
SPARCS 成功地在无需心电图门控或屏气的情况下成像心脏功能。使用每片 8 秒的数据采集，在<90 秒的自由呼吸采集时间内，可以获得具有临床可接受的空间和时间分辨率以及图像质量的全心脏电影图像。
