Department of Diagnostic and Interventional Radiology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Berlin, Germany.
J Cardiovasc Magn Reson. 2019 Sep 19;21(1):60. doi: 10.1186/s12968-019-0570-3.
This study develops a model-based myocardial T1 mapping technique with sparsity constraints which employs a single-shot inversion-recovery (IR) radial fast low angle shot (FLASH) cardiovascular magnetic resonance (CMR) acquisition. The method should offer high resolution, accuracy, precision and reproducibility.
The proposed reconstruction estimates myocardial parameter maps directly from undersampled k-space which is continuously measured by IR radial FLASH with a 4 s breathhold and retrospectively sorted based on a cardiac trigger signal. Joint sparsity constraints are imposed on the parameter maps to further improve T1 precision. Validations involved studies of an experimental phantom and 8 healthy adult subjects.
In comparison to an IR spin-echo reference method, phantom experiments with T1 values ranging from 300 to 1500 ms revealed good accuracy and precision at simulated heart rates between 40 and 100 bpm. In vivo T1 maps achieved better precision and qualitatively better preservation of image features for the proposed method than a real-time CMR approach followed by pixelwise fitting. Apart from good inter-observer reproducibility (0.6% of the mean), in vivo results confirmed good intra-subject reproducibility (1.05% of the mean for intra-scan and 1.17, 1.51% of the means for the two inter-scans, respectively) of the proposed method.
Model-based reconstructions with sparsity constraints allow for single-shot myocardial T1 maps with high spatial resolution, accuracy, precision and reproducibility within a 4 s breathhold. Clinical trials are warranted.
本研究开发了一种基于模型的心肌 T1 映射技术，具有稀疏约束，采用单次反转恢复（IR）径向快速低角度采集（FLASH）心血管磁共振（CMR）采集。该方法应具有高分辨率、准确性、精度和可重复性。
所提出的重建方法直接从欠采样的 k 空间估计心肌参数图，该 k 空间由 IR 径向 FLASH 连续测量，屏气 4 秒，并根据心脏触发信号进行回顾性排序。对参数图施加联合稀疏约束，以进一步提高 T1 精度。验证涉及实验性体模和 8 名健康成年受试者的研究。
与 IR 自旋回波参考方法相比，在模拟心率为 40 至 100bpm 时，T1 值范围为 300 至 1500ms 的体模实验具有良好的准确性和精度。与实时 CMR 方法后进行像素拟合相比，体内 T1 图具有更好的精度和图像特征的定性保留。除了良好的观察者间可重复性（平均值的 0.6%）外，体内结果还证实了所提出方法的良好的受试者内可重复性（同一扫描内的平均值的 1.05%，两次扫描之间的平均值分别为 1.17%和 1.51%）。
具有稀疏约束的基于模型的重建允许在 4 秒屏气时间内实现单次心肌 T1 图的高空间分辨率、准确性、精度和可重复性。需要进行临床试验。
