Department of Diagnostic, Interventional and Pediatric Radiology (DIPR), Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Translation Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland.
Magn Reson Med. 2023 Sep;90(3):922-938. doi: 10.1002/mrm.29680. Epub 2023 Apr 27.
To develop a free-running 3D radial whole-heart multiecho gradient echo (ME-GRE) framework for cardiac- and respiratory-motion-resolved fat fraction (FF) quantification.
(N = 8) readouts optimized for water-fat separation and quantification were integrated within a continuous non-electrocardiogram-triggered free-breathing 3D radial GRE acquisition. Motion resolution was achieved with pilot tone (PT) navigation, and the extracted cardiac and respiratory signals were compared to those obtained with self-gating (SG). After extra-dimensional golden-angle radial sparse parallel-based image reconstruction, FF, R *, and B maps, as well as fat and water images were generated with a maximum-likelihood fitting algorithm. The framework was tested in a fat-water phantom and in 10 healthy volunteers at 1.5 T using N = 4 and N = 8 echoes. The separated images and maps were compared with a standard free-breathing electrocardiogram (ECG)-triggered acquisition.
The method was validated in vivo, and physiological motion was resolved over all collected echoes. Across volunteers, PT provided respiratory and cardiac signals in agreement (r = 0.91 and r = 0.72) with SG of the first echo, and a higher correlation to the ECG (0.1% of missed triggers for PT vs. 5.9% for SG). The framework enabled pericardial fat imaging and quantification throughout the cardiac cycle, revealing a decrease in FF at end-systole by 11.4% ± 3.1% across volunteers (p < 0.0001). Motion-resolved end-diastolic 3D FF maps showed good correlation with ECG-triggered measurements (FF bias of -1.06%). A significant difference in free-running FF measured with N = 4 and N = 8 was found (p < 0.0001 in sub-cutaneous fat and p < 0.01 in pericardial fat).
Free-running fat fraction mapping was validated at 1.5 T, enabling ME-GRE-based fat quantification with N = 8 echoes in 6:15 min.
开发一种自由运行的 3D 径向全心脏多回波梯度回波（ME-GRE）框架，用于心脏和呼吸运动分辨脂肪分数（FF）定量。
（N=8）优化用于水脂分离和定量的读出信号被整合到连续非心电图触发的自由呼吸 3D 径向 GRE 采集。运动分辨率通过导频音（PT）导航实现，并将提取的心脏和呼吸信号与自门控（SG）获得的信号进行比较。在多维黄金角径向稀疏并行图像重建后，使用最大似然拟合算法生成 FF、R*和 B 图，以及脂肪和水图像。该框架在 1.5T 下的水脂体模和 10 名健康志愿者中进行了测试，使用 N=4 和 N=8 个回波。将分离的图像和地图与标准的自由呼吸心电图（ECG）触发采集进行比较。
该方法在体内得到验证，并在所有采集的回波上都能分辨生理运动。在志愿者中，PT 提供的呼吸和心脏信号与第一回波的 SG 一致（r=0.91 和 r=0.72），与 ECG 的相关性更高（PT 触发漏检率为 0.1%，SG 为 5.9%）。该框架能够在整个心动周期内进行心包脂肪成像和定量，显示志愿者的心衰末期 FF 降低了 11.4%±3.1%（p<0.0001）。运动分辨舒张末期 3D FF 地图与 ECG 触发测量具有良好的相关性（FF 偏差为-1.06%）。在 N=4 和 N=8 时，自由运行的 FF 测量值存在显著差异（皮下脂肪 p<0.0001，心包脂肪 p<0.01）。
在 1.5T 下验证了自由运行的脂肪分数映射，实现了使用 N=8 个回波在 6:15 分钟内进行 ME-GRE 基础的脂肪定量。
Zotero 插件