Objective

To establish and optimize a stable 3 Tesla (T) glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging protocol for assessing the articular cartilage of the tibiotalar joint in healthy volunteers and patients after a sustained injury to the ankle.

Methods

Using Bloch–McConnell simulations, we optimized the sequence protocol for a 3 T MRI scanner for maximum gagCEST effect size within a clinically feasible time frame of less than 07:30 min. This protocol was then used to analyze the gagCEST effect of the articular cartilage of the tibiotalar joint of 17 healthy volunteers and five patients with osteochondral lesions of the talus following ankle trauma. Reproducibility was tested with the intraclass correlation coefficient.

Results

The mean magnetization transfer ratio asymmetry (MTR_asym), i.e., the gagCEST effect size, was significantly lower in patients than in healthy volunteers (0.34 ± 1.9% vs. 1.49 ± 0.11%; p < 0.001 [linear mixed model]). Intra- and inter-rater reproducibility was excellent with an average measure intraclass correlation coefficient (ICC) of 0.97 and a single measure ICC of 0.91 (p < 0.01).

Discussion

In this feasibility study, pre-morphological tibiotalar joint cartilage damage was quantitatively assessable on the basis of the optimized 3 T gagCEST imaging protocol that allowed stable quantification gagCEST effect sizes across a wide range of health and disease in clinically feasible acquisition times.

中文翻译：

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使用 3 T gagCEST 成像检测胫距关节早期软骨退化：可行性研究。

客观的

建立和优化稳定的 3 特斯拉 (T) 糖胺聚糖化学交换饱和转移 (gagCEST) 成像协议，用于评估健康志愿者和踝关节持续损伤后患者胫距关节的关节软骨。

方法

使用 Bloch-McConnell 模拟，我们优化了 3 T MRI 扫描仪的序列协议，以在小于 07:30 分钟的临床可行时间范围内获得最大的 gagCEST 效应大小。然后使用该协议来分析 17 名健康志愿者和 5 名踝外伤后距骨骨软骨病变患者的胫距关节软骨的 gagCEST 效应。用组内相关系数测试可重复性。

结果

患者的平均磁化转移比不对称性 (MTR _asym )，即 gagCEST 效应大小，显着低于健康志愿者（0.34 ± 1.9% 与 1.49 ± 0.11%；p  < 0.001 [线性混合模型]）。内部和内部评估者的可重复性非常好，平均测量类内相关系数 (ICC) 为 0.97，单一测量 ICC 为 0.91 ( p  < 0.01)。

讨论

在这项可行性研究中，基于优化的 3 T gagCEST 成像协议对形态学前的胫距关节软骨损伤进行了定量评估，该协议允许在临床可行的采集时间内在广泛的健康和疾病范围内稳定量化 gagCEST 效应大小。