Objective

MRI is a reliable and accurate technique to characterize rheumatoid arthritis. The aim of this study was to provide voxel-by-voxel 3D maps of the proton density fat fraction (PDFF), the T₁ of water (T_1W), the T₁ of fat (T_1F), the T₂* of water (T₂*_W), the T₂* of fat (T₂*_F) in the wrist bone marrow.

Materials and methods

The experiments were conducted on 14 healthy volunteers (mean age: 24 ± 4). The data were acquired at 1.5 T using two optimized four-echo 3D 1.2 × 1.2 × 1.2 mm³-isotropic spoiled gradient sequences. A repeatability study was carried out. The measurements were done using a homemade parametric viewer software.

Results

The inter-volunteer results were, on average: PDFF = 86 ± 3%, T_1W = 441 ± 113 ms, T_1F = 245 ± 19 ms, T₂*_W = 6 ± 1 ms and T₂*_F = 16 ± 3 ms. The coefficients of variation were for fat based biomarkers CV_PDFF < 5%, CV_T1F < 15% and CV_T2*F < 10% in the repeatability study.

Discussion

The protocol and quantification tool proposed in this study provide high-resolution voxel-by-voxel 3D maps of five biomarkers in the wrist in less than 4 min of acquisition.

中文翻译：

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腕骨髓中五种 MR 生物标志物的基于体素的映射

客观的

MRI 是表征类风湿性关节炎的可靠且准确的技术。本研究的目的是提供质子密度脂肪分数 (PDFF)、水的T ₁ ( T _1W )、脂肪的 T ₁ ( T _1F )、脂肪的T ₂ * 的逐体素 3D 图。水（Ť ₂ * _{w ^}），则Ť ₂的脂肪*（Ť ₂ * _˚F）在手腕骨髓。

材料和方法

实验是在 14 名健康志愿者（平均年龄：24 ± 4）上进行的。使用两个优化的四回波 3D 1.2 × 1.2 × 1.2 mm ³各向同性破坏梯度序列在 1.5 T 下采集数据。进行了重复性研究。测量是使用自制的参数查看器软件完成的。

结果

志愿者间的结果平均为：PDFF = 86 ± 3%，T _1W  = 441 ± 113 ms，T _1F  = 245 ± 19 ms，T ₂ * _W  = 6 ± 1 ms 和T ₂ * _F  = 16 ± 3 毫秒。 在重复性研究中，变异系数针对基于脂肪的生物标志物 CV _PDFF  < 5%、CV _{T 1F}  < 15% 和 CV _{T 2*F} < 10%。

讨论

本研究中提出的协议和量化工具可在不到 4 分钟的采集时间内提供手腕中五种生物标志物的高分辨率逐体素 3D 图。