Radiology, Northshore University HealthSystem, Evanston, IL, USA.
Radiology, Northwestern Memorial Hospital, Chicago, IL, USA.
J Cardiovasc Magn Reson. 2018 Feb 19;20(1):12. doi: 10.1186/s12968-018-0433-3.
Existing cine imaging techniques rely on balanced steady-state free precession (bSSFP) or spoiled gradient-echo readouts, each of which has limitations. For instance, with bSSFP, artifacts occur from rapid through-plane flow and off-resonance effects. We hypothesized that a prototype cine technique, radial fast interrupted steady-state (FISS), could overcome these limitations. The technique was compared with standard cine bSSFP for cardiac function, coronary artery conspicuity, and aortic valve morphology. Given its advantageous properties, we further hypothesized that the cine FISS technique, in combination with arterial spin labeling (ASL), could provide an alternative to phase contrast for visualizing in-plane flow patterns within the aorta and branch vessels.
The study was IRB-approved and subjects provided consent. Breath-hold cine FISS and bSSFP were acquired using similar imaging parameters. There was no significant difference in biplane left ventricular ejection fraction or cardiac image quality between the two techniques. Compared with cine bSSFP, cine FISS demonstrated a marked decrease in fat signal which improved conspicuity of the coronary arteries, while suppression of through-plane flow artifact on thin-slice cine FISS images improved visualization of the aortic valve. Banding artifacts in the subcutaneous tissues were reduced. In healthy subjects, dynamic flow patterns were well visualized in the aorta, coronary and renal arteries using cine FISS ASL, even when the slice was substantially thicker than the vessel diameter.
Cine FISS demonstrates several benefits for cardiovascular imaging compared with cine bSSFP, including better suppression of fat signal and reduced artifacts from through-plane flow and off-resonance effects. The main drawback is a slight (~ 20%) decrease in temporal resolution. In addition, preliminary results suggest that cine FISS ASL provides a potential alternative to phase contrast techniques for in-plane flow quantification, while enabling an efficient, visually-appealing, semi-projective display of blood flow patterns throughout the course of an artery and its branches.
现有的电影成像技术依赖于平衡稳态自由进动（bSSFP）或扰相梯度回波读出，每种技术都有其局限性。例如，在 bSSFP 中，由于快速的横过平面流动和离共振效应会产生伪影。我们假设一种原型电影技术，径向快速中断稳态（FISS），可以克服这些限制。该技术与标准电影 bSSFP 进行了心脏功能、冠状动脉显影和主动脉瓣形态的比较。鉴于其有利的特性，我们进一步假设电影 FISS 技术与动脉自旋标记（ASL）相结合，可以为可视化主动脉及其分支血管内的平面内流动模式提供替代相位对比的方法。
该研究获得了机构审查委员会的批准，受试者提供了同意。使用类似的成像参数获取屏气电影 FISS 和 bSSFP。两种技术之间的双平面左心室射血分数或心脏图像质量没有显著差异。与电影 bSSFP 相比，电影 FISS 显著降低了脂肪信号，提高了冠状动脉的显影，而在薄层电影 FISS 图像上抑制了平面内流动伪影，改善了主动脉瓣的可视化。皮下组织中的带状伪影减少。在健康受试者中，使用电影 FISS ASL 可以很好地可视化主动脉、冠状动脉和肾动脉中的动态流动模式，即使切片厚度明显大于血管直径。
与电影 bSSFP 相比，电影 FISS 显示出对心血管成像的多种优势，包括更好地抑制脂肪信号和减少平面内流动和离共振效应产生的伪影。主要缺点是时间分辨率略有下降（约 20%）。此外，初步结果表明，电影 FISS ASL 为平面内流量定量提供了一种替代相位对比技术的潜在方法，同时能够有效地、以吸引人的半投影方式显示整个动脉及其分支的血流模式。
