Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA.
Siemens Medical Solutions USA, Inc., Los Angeles, California, USA.
Magn Reson Med. 2021 Dec;86(6):3182-3191. doi: 10.1002/mrm.28935. Epub 2021 Jul 26.
To develop a single-scan method for -corrected T mapping and apply it for free-breathing (FB) cardiac MR multitasking without electrocardiogram (ECG) triggering.
One dual flip-angle (2FA) inversion recovery (IR)-FLASH scan provides two observations of (apparent T ) corresponding to two distinct combinations of the nominal FA α and . Spatiotemporally coregistered T and spin history maps are obtained by fitting the 2FA signal model. T estimate accuracy and repeatability for single flip-angle (1FA) and 2FA IR-FLASH sequence MR multitasking were evaluated at 3T. A T phantom was first imaged on the scanner table, then on two human subjects' thoraxes in both breath-hold (BH) and FB conditions. IR-turbo spin echo (IR-TSE) static phantom T measurements served as reference. In 10 healthy subjects, myocardial T was evaluated with ECG-free, FB multitasking sequences alongside ECG-triggered BH MOLLI.
For phantom-on-table T estimates, 2FA agreed better with IR-TSE (intraclass correlation coefficient [ICC] = 0.996, mean error ± SD = -1.6% ± 1.9%) than did 1FA (ICC = 0.922; mean error ± SD = -4.3% ± 12%). For phantom-on-thorax, 2FA was more repeatable and robust to respiration than 1FA (coefficient of variation [CoV] = 1.2% 2FA, = 11.3% 1FA). In vivo, in intrasession T repeatability, 2FA (septal CoV = 2.4%, six-segment CoV = 4.4%) outperformed 1FA (septal CoV = 3.1%, six-segment CoV = 5.5%). In six-segment T homogeneity, 2FA (CoV = 7.9%) also outperformed 1FA (CoV = 11.1%).
The 2FA IR-FLASH improves T estimate accuracy and repeatability over 1FA IR-FLASH, and enables single-scan -corrected T mapping without BHs or ECG when used with MR multitasking.
开发一种用于校正 T 映射的单次扫描方法，并将其应用于无需心电图 (ECG) 触发的自由呼吸 (FB) 心脏磁共振多任务成像。
单次双翻转角 (2FA) 反转恢复 (IR)-FLASH 扫描可提供两个对应于名义翻转角 (FA)α和的两个不同组合的观测值（表观 T）。通过拟合 2FA 信号模型，获得时空配准的 T 和自旋历史图。在 3T 上评估了单翻转角 (1FA) 和 2FA IR-FLASH 序列多任务成像的 T 估计准确性和可重复性。首先在扫描仪台上对 T 体模进行成像，然后在两个人体胸部进行屏气 (BH) 和 FB 两种条件下的成像。IR-涡轮自旋回波 (IR-TSE) 静态体模 T 测量作为参考。在 10 名健康受试者中，使用无 ECG、FB 多任务成像序列评估心肌 T，同时进行 ECG 触发 BH MOLLI。
对于体模台上的 T 估计值，2FA 与 IR-TSE 的一致性更好（组内相关系数 [ICC] = 0.996，平均误差 ± SD = -1.6% ± 1.9%），而 1FA 的一致性较差（ICC = 0.922；平均误差 ± SD = -4.3% ± 12%）。对于体模在胸部的情况，2FA 比 1FA 更具可重复性且对呼吸更稳健（变异性 [CoV] = 1.2% 2FA，= 11.3% 1FA）。在体内，在单次扫描 T 重复性方面，2FA（间隔 CoV = 2.4%，六节段 CoV = 4.4%）优于 1FA（间隔 CoV = 3.1%，六节段 CoV = 5.5%）。在六节段 T 均匀性方面，2FA（CoV = 7.9%）也优于 1FA（CoV = 11.1%）。
2FA IR-FLASH 提高了 T 估计的准确性和重复性，优于 1FA IR-FLASH，并且当与磁共振多任务成像结合使用时，可以在不进行 BH 和 ECG 的情况下实现单次扫描校正 T 映射。
