Ingle R Reeve, Santos Juan M, Overall William R, McConnell Michael V, Hu Bob S, Nishimura Dwight G
Magnetic Resonance Systems Research Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California, USA.
Magn Reson Med. 2015 May;73(5):1764-74. doi: 10.1002/mrm.25291. Epub 2014 May 7.
To develop a self-gated alternating repetition time balanced steady-state free precession (ATR-SSFP) pulse sequence for fat-suppressed cardiac cine imaging.
Cardiac gating is computed retrospectively using acquired magnetic resonance self-gating data, enabling cine imaging without the need for electrocardiogram (ECG) gating. Modification of the slice-select rephasing gradients of an ATR-SSFP sequence enables the acquisition of a one-dimensional self-gating readout during the unused short repetition time (TR). Self-gating readouts are acquired during every TR of segmented, breath-held cardiac scans. A template-matching algorithm is designed to compute cardiac trigger points from the self-gating signals, and these trigger points are used for retrospective cine reconstruction. The proposed approach is compared with ECG-gated ATR-SSFP and balanced steady-state free precession in 10 volunteers and five patients.
The difference of ECG and self-gating trigger times has a variability of 13 ± 11 ms (mean ± SD). Qualitative reviewer scoring and ranking indicate no statistically significant differences (P > 0.05) between self-gated and ECG-gated ATR-SSFP images. Quantitative blood-myocardial border sharpness is not significantly different among self-gated ATR-SSFP ( 0.61±0.15 mm -1), ECG-gated ATR-SSFP ( 0.61±0.15 mm -1), or conventional ECG-gated balanced steady-state free precession cine MRI ( 0.59±0.15 mm -1).
The proposed self-gated ATR-SSFP sequence enables fat-suppressed cardiac cine imaging at 1.5 T without the need for ECG gating and without decreasing the imaging efficiency of ATR-SSFP.
研发一种用于脂肪抑制心脏电影成像的自门控交替重复时间平衡稳态自由进动（ATR-SSFP）脉冲序列。
使用采集到的磁共振自门控数据进行回顾性心脏门控计算，从而实现无需心电图（ECG）门控的电影成像。对ATR-SSFP序列的层面选择重聚梯度进行修改，能够在未使用的短重复时间（TR）期间采集一维自门控读出信号。在分段屏气心脏扫描的每个TR期间采集自门控读出信号。设计一种模板匹配算法，根据自门控信号计算心脏触发点，这些触发点用于回顾性电影重建。将所提出的方法与10名志愿者和5名患者的ECG门控ATR-SSFP及平衡稳态自由进动进行比较。
ECG和自门控触发时间的差异具有13±11 ms（均值±标准差）的变异性。定性的评估者评分和排名表明，自门控和ECG门控的ATR-SSFP图像之间无统计学显著差异（P>0.05）。自门控ATR-SSFP（0.61±0.15 mm -1）、ECG门控ATR-SSFP（0.61±0.15 mm -1）或传统ECG门控平衡稳态自由进动心脏电影磁共振成像（0.59±0.15 mm -1）之间的定量血-心肌边界清晰度无显著差异。
所提出的自门控ATR-SSFP序列能够在1.5 T场强下实现脂肪抑制心脏电影成像，无需ECG门控且不降低ATR-SSFP的成像效率。
