Purpose

To assess the correlation of peripheral nerve and skeletal muscle magnetization transfer ratio (MTR) with demographic variables.

Methods

In this study 59 healthy adults evenly distributed across 6 decades (mean age 50.5 years ±17.1, 29 women) underwent magnetization transfer imaging and high-resolution T2-weighted imaging of the sciatic nerve at 3 T. Mean sciatic nerve MTR as well as MTR of biceps femoris and vastus lateralis muscles were calculated based on manual segmentation on six representative slices. Correlations of MTR with age, body height, body weight, and body mass index (BMI) were expressed by Pearson coefficients. Best predictors for nerve and muscle MTR were determined using a multiple linear regression model with forward variable selection and fivefold cross-validation.

Results

Sciatic nerve MTR showed significant negative correlations with age (r = −0.47, p < 0.001), BMI (r = −0.44, p < 0.001), and body weight (r = −0.36, p = 0.006) but not with body height (p = 0.55). The multiple linear regression model determined age and BMI as best predictors for nerve MTR (R² = 0.40). The MTR values were different between nerve and muscle tissue (p < 0.0001), but similar between muscles. Muscle MTR was associated with BMI (r = −0.46, p < 0.001 and r = −0.40, p = 0.002) and body weight (r = −0.36, p = 0.005 and r = −0.28, p = 0.035). The BMI was selected as best predictor for mean muscle MTR in the multiple linear regression model (R² = 0.26).

Conclusion

Peripheral nerve MTR decreases with higher age and BMI. Studies that assess peripheral nerve MTR should consider age and BMI effects. Skeletal muscle MTR is primarily associated with BMI but overall less dependent on demographic variables.

中文翻译：

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外周神经与骨骼肌的磁化传递比

目的

评估周围神经和骨骼肌磁化传递比 (MTR) 与人口统计学变量的相关性。

方法

在这项研究中，59 名健康成人均匀分布在 6 个年代（平均年龄 50.5 岁 ±17.1 岁，29 名女性）接受了 3 T 的坐骨神经磁化转移成像和高分辨率 T2 加权成像。平均坐骨神经 MTR 和 MTR基于对六个代表性切片的手动分割计算了股二头肌和股外侧肌的肌肉量。MTR 与年龄、身高、体重和体重指数 (BMI) 的相关性由 Pearson 系数表示。使用具有前向变量选择和五重交叉验证的多元线性回归模型确定神经和肌肉 MTR 的最佳预测因子。

结果

坐骨神经 MTR 与年龄 (r = -0.47, p  < 0.001)、BMI (r = -0.44, p  < 0.001) 和体重 (r = -0.36, p  = 0.006) 呈显着负相关，但与身高无关( p  = 0.55)。多元线性回归模型将年龄和 BMI 确定为神经 MTR 的最佳预测因子 (R ²  = 0.40)。神经和肌肉组织的 MTR 值不同 ( p  < 0.0001)，但肌肉之间的 MTR 值相似。肌肉 MTR 与 BMI (r = -0.46, p  < 0.001 and r = -0.40, p  = 0.002) 和体重 (r = -0.36, p  = 0.005 and r = -0.28, p = 0.035)。在多元线性回归模型中，BMI 被选为平均肌肉 MTR 的最佳预测因子（R ²  = 0.26）。

结论

周围神经 MTR 随年龄和 BMI 升高而降低。评估周围神经 MTR 的研究应考虑年龄和 BMI 影响。骨骼肌 MTR 主要与 BMI 相关，但总体上较少依赖人口统计变量。