Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA.
School of Medicine, University Medical Line, Stanford University, Stanford, CA, USA.
MAGMA. 2023 Dec;36(6):857-867. doi: 10.1007/s10334-023-01116-9. Epub 2023 Sep 4.
To develop two spiral-based bSSFP pulse sequences combined with L + S reconstruction for accelerated ungated, free-breathing dynamic cardiac imaging at 1.5 T.
Tiny golden angle rotated spiral-out and spiral-in/out bSSFP sequences combined with view-sharing (VS), compressed sensing (CS), and low-rank plus sparse (L + S) reconstruction were evaluated and compared via simulation and in vivo dynamic cardiac imaging studies. The proposed methods were then validated against the standard cine, in terms of quantitative image assessment and qualitative quality rating.
The L + S method yielded the least residual artifacts and the best image sharpness among the three methods. Both spiral cine techniques showed clinically diagnostic images (score > 3). Compared to standard cine, there were significant differences in global image quality and edge sharpness for spiral cine techniques, while there was significant difference in image contrast for the spiral-out cine but no significant difference for the spiral-in/out cine. There was good agreement in left ventricular ejection fraction for both the spiral-out cine (- 1.6 [Formula: see text] 3.1%) and spiral-in/out cine (- 1.5 [Formula: see text] 2.8%) against standard cine.
Compared to the time-consuming standard cine (~ 5 min) which requires ECG-gating and breath-holds, the proposed spiral bSSFP sequences achieved ungated, free-breathing cardiac movies at a similar spatial (1.5 × 1.5 × 8 mm) and temporal resolution (36 ms) per slice for whole heart coverage (10-15 slices) within 45 s, suggesting the clinical potential for improved patient comfort or for imaging patients with arrhythmias or who cannot hold their breath.
开发两种基于螺旋的 bSSFP 脉冲序列，结合 L+S 重建，用于在 1.5T 下加速非门控、自由呼吸的动态心脏成像。
通过模拟和体内动态心脏成像研究，评估和比较了微小黄金角旋转螺旋出和螺旋进/出 bSSFP 序列，结合视图共享（VS）、压缩感知（CS）和低秩稀疏（L+S）重建。然后，将这些方法与标准电影进行了对比，从定量图像评估和定性质量评分两个方面进行了验证。
L+S 方法产生的残余伪影最少，图像锐度最好。两种螺旋电影技术均显示出临床诊断图像（评分>3）。与标准电影相比，螺旋电影技术在整体图像质量和边缘锐度方面有显著差异，而在螺旋出电影中图像对比度有显著差异，而在螺旋进/出电影中则没有显著差异。螺旋出电影（-1.6 [公式：见正文] 3.1%）和螺旋进/出电影（-1.5 [公式：见正文] 2.8%）的左心室射血分数与标准电影有很好的一致性。
与需要心电图门控和屏气的耗时的标准电影（约 5 分钟）相比，所提出的螺旋 bSSFP 序列在相同的空间（1.5×1.5×8mm）和时间分辨率（36ms）下，每片（10-15 片）实现了非门控、自由呼吸的心脏电影，全心脏覆盖范围在 45 秒内完成，这表明该技术具有改善患者舒适度的临床潜力，或者用于成像心律失常或无法屏气的患者。
