Calarnou Pauline, Ogier Augustin C, Roy Christopher W, Rocca Angela, Abdurashidova Tamila, Ledoux Jean-Baptiste, Hullin Roger, Bustin Aurélien, Yerly Jérôme, van Heeswijk Ruud B
Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
Cardiology Service, Cardiovascular Department, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.
Magn Reson Med. 2025 Oct;94(4):1577-1591. doi: 10.1002/mrm.30588. Epub 2025 Jun 2.
To implement a navigator-gated free-breathing 2D radial joint T-T mapping technique for the myocardium at 3T, and to characterize the impact of the navigator rejection on the precision and accuracy of the T and T maps.
The proposed technique, named PARMANav (for PArametric Radial Mapping with Navigator gating), collects 25 lung-liver navigator-gated electrocardiogram (ECG)-triggered single-shot radial gradient-recalled echo (GRE) images with five magnetization preparations. Source images were reconstructed using compressed sensing. Extended-phase-graph simulations were used to generate an acquisition-specific joint T-T dictionary. The impact of the number of rejected navigators on the relaxation times was assessed in numerical simulations. The influence of the navigator acceptance window width (NAWW) and heart rate on the relaxation times was assessed in phantom studies, 10 healthy volunteers, and 3 patients. The relaxation times were compared to routine T and T mapping values.
The numerical simulations showed negligible dependence on the number of rejected navigators (<6% T-T variation). In the phantom, PARMANav T-T values were stable across heart rates: the T-T coefficient of variation (CoV) was <3%. As expected from literature, in-vivo PARMANav T-T values were higher than routine values (T = 1331 ± 53 ms, T = 46.1 ± 2.5 ms vs. T = 1095 ± 81 ms, T = 38.7 ± 2.9 ms, p < 0.001), while the PARMANav T CoV was significantly reduced. No myocardial T-T values or CoV trend was observed for the different NAWW. Feasibility in patients was demonstrated, where high-quality maps were obtained.
PARMANav allows for precise and accurate joint T-T mapping without requiring breath holding. Through-plane motion artifacts were avoided with a navigator that did not impact the accuracy or precision of the resulting maps.
在3T条件下，为心肌实施一种导航门控自由呼吸二维径向联合T-T映射技术，并描述导航器剔除对T和T映射的精度和准确性的影响。
所提出的技术名为PARMANav（用于带导航门控的参数化径向映射），收集25幅肺-肝导航门控心电图（ECG）触发的单次激发径向梯度回波（GRE）图像，具有五种磁化准备。源图像使用压缩感知进行重建。扩展相位图模拟用于生成特定采集的联合T-T字典。在数值模拟中评估被剔除导航器数量对弛豫时间的影响。在体模研究、10名健康志愿者和3名患者中评估导航器接受窗口宽度（NAWW）和心率对弛豫时间的影响。将弛豫时间与常规T和T映射值进行比较。
数值模拟显示对被剔除导航器数量的依赖性可忽略不计（T-T变化<6%）。在体模中，PARMANav的T-T值在不同心率下稳定：T-T变异系数（CoV）<3%。正如文献所预期的，体内PARMANav的T-T值高于常规值（T = 1331±53 ms，T = 46.1±2.5 ms对比T = 1095±81 ms，T = 38.7±2.9 ms，p < 0.001），而PARMANav的T CoV显著降低。对于不同的NAWW，未观察到心肌T-T值或CoV趋势。在患者中证明了可行性，获得了高质量的映射图。
PARMANav允许在无需屏气的情况下进行精确准确的联合T-T映射。通过使用不影响所得映射图准确性或精度的导航器避免了层面间运动伪影。
