Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California, USA.
General Electric Healthcare, Calgary, Alberta, Canada.
Magn Reson Med. 2021 Oct;86(4):2234-2249. doi: 10.1002/mrm.28849. Epub 2021 May 25.
To develop and evaluate an efficient precontrast T mapping technique suitable for quantitative high-resolution whole-brain dynamic contrast-enhanced-magnetic resonance imaging (DCE-MRI).
Variable flip angle (VFA) T mapping was considered that provides 1 × 1 × 2 mm resolution to match a recent high-resolution whole-brain DCE-MRI protocol. Seven FAs were logarithmically spaced from 1.5° to 15°. T and M maps were estimated using model-based reconstruction. This approach was evaluated using an anatomically realistic brain tumor digital reference object (DRO) with noise-mimicking 3T neuroimaging and fully sampled data acquired from one healthy volunteer. Methods were also applied on fourfold prospectively undersampled VFA data from 13 patients with high-grade gliomas.
T -mapping precision decreased with undersampling factor R, althoughwhereas bias remained small before a critical R. In the noiseless DRO, T bias was <25 ms in white matter (WM) and <11 ms in brain tumor (BT). T standard deviation (SD) was <119.5 ms in WM (coefficient of variation [COV] ~11.0%) and <253.2 ms in BT (COV ~12.7%). In the noisy DRO, T bias was <50 ms in WM and <30 ms in BT. For R ≤ 10, T SD was <107.1 ms in WM (COV ~9.9%) and <240.9 ms in BT (COV ~12.1%). In the healthy subject, T bias was <30 ms for R ≤ 16. At R = 4, T SD was 171.4 ms (COV ~13.0%). In the prospective brain tumor study, T values were consistent with literature values in WM and BT.
High-resolution whole-brain VFA T mapping is feasible with sparse sampling, supporting its use for quantitative DCE-MRI.
开发并评估一种适用于定量高分辨率全脑动态对比增强磁共振成像（DCE-MRI）的高效预对比 T 映射技术。
考虑采用可变翻转角（VFA）T 映射技术，以提供 1×1×2mm 的分辨率，与最近的高分辨率全脑 DCE-MRI 方案相匹配。从 1.5°到 15°对数间隔 7 个 FA。使用基于模型的重建来估计 T 和 M 图谱。该方法使用具有噪声模拟 3T 神经影像学和从一名健康志愿者获得的全采样数据的解剖逼真脑肿瘤数字参考对象（DRO）进行了评估。该方法还应用于 13 例高级别胶质瘤患者的四倍前瞻性欠采样 VFA 数据。
T 映射精度随欠采样因子 R 降低，尽管在关键 R 之前，偏差仍然很小。在无噪声 DRO 中，脑白质（WM）中的 T 偏差<25ms，脑肿瘤（BT）中的 T 偏差<11ms。WM 中的 T 标准偏差（SD）<119.5ms（变异系数[COV]11.0%），BT 中的 T 标准偏差<253.2ms（COV12.7%）。在有噪声的 DRO 中，WM 中的 T 偏差<50ms，BT 中的 T 偏差<30ms。对于 R≤10，WM 中的 T SD<107.1ms（COV9.9%），BT 中的 T SD<240.9ms（COV12.1%）。在健康受试者中，R≤16 时 T 偏差<30ms。在 R=4 时，T SD 为 171.4ms（COV~13.0%）。在前瞻性脑肿瘤研究中，WM 和 BT 中的 T 值与文献值一致。
高分辨率全脑 VFA T 映射在稀疏采样下是可行的，支持其用于定量 DCE-MRI。
