Department of Neurology, Heimer Institute for Muscle Research, BG-University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany.
Department of Neurology, University Hospital St. Josef, Ruhr-University Bochum, Bochum, Germany.
J Neuromuscul Dis. 2021;8(6):949-962. doi: 10.3233/JND-210660.
Myotonic Dystrophies type 1 and type 2 are hereditary myopathies with dystrophic muscle degeneration in varying degrees. Differences in muscle diffusion between both diseases have not been evaluated yet.
To evaluate the ability of muscle diffusion tensor imaging (mDTI) and Dixon fat-quantification to distinguish between Myotonic Dystrophy (DM) type 1 and type 2 and if both diseases show distinct muscle involvement patterns.
We evaluated 6 thigh and 7 calf muscles (both legs) of 10 DM 1, 13 DM 2 and 28 healthy controls (HC) with diffusion tensor imaging, T1w and mDixonquant sequences in a 3T MRI scanner. The quantitative mDTI-values axial diffusivity (λ1), mean diffusivity (MD), radial diffusivity (RD) and fractional anisotropy (FA) as well as fat-fraction were analysed. CTG-triplet repeat-length of DM 1 patients was correlated with diffusion metrics and fat-fraction.
mDTI showed significant differences between DM 1 and DM 2 vs. healthy controls in diffusion parameters of the thigh (all p < 0.001) except for FA (p = 0.0521 / 0.8337). In calf muscles mDTI showed significant differences between DM 1 and DM 2 patients (all p < 0.0001) as well as between DM 1 patients and controls (all p = 0.0001). Thigh muscles had a significant higher fat-fraction in both groups vs. controls (p < 0.05). There was no correlation of CTG triplet length with mDTI values and fat-fraction.
mDTI reveals specific changes of the diffusion parameters and fat-fraction in muscles of DM 1 and DM 2 patients. Thus, the quantitative MRI methods presented in this study provide a powerful tool in differential diagnosis and follow-up of DM 1 and DM 2, however, the data must be validated in larger studies.
1 型和 2 型强直性肌营养不良症是具有不同程度肌肉变性的遗传性肌病。两种疾病之间的肌肉弥散差异尚未得到评估。
评估肌肉弥散张量成像（mDTI）和 Dixon 脂肪定量技术区分强直性肌营养不良（DM）1 型和 2 型的能力，以及两种疾病是否表现出不同的肌肉受累模式。
我们在 3T MRI 扫描仪上评估了 10 例 DM1、13 例 DM2 和 28 例健康对照者（HC）的 6 条大腿和 7 条小腿肌肉（双侧）的弥散张量成像、T1w 和 mDixonquant 序列。分析了定量 mDTI 值（λ1、MD、RD 和 FA）以及脂肪分数。DM1 患者的 CTG 三核苷酸重复长度与弥散指标和脂肪分数相关。
mDTI 在大腿肌肉的弥散参数方面显示出 DM1 和 DM2 与 HC 之间的显著差异（所有 p<0.001），除了 FA（p=0.0521/0.8337）。在小腿肌肉中，mDTI 在 DM1 和 DM2 患者之间（所有 p<0.0001）以及 DM1 患者和 HC 之间（所有 p=0.0001）均存在显著差异。大腿肌肉的脂肪分数在两组中均显著高于 HC（p<0.05）。CTG 三核苷酸长度与 mDTI 值和脂肪分数之间无相关性。
mDTI 显示出 DM1 和 DM2 患者肌肉的弥散参数和脂肪分数的特定变化。因此，本研究中提出的定量 MRI 方法为 DM1 和 DM2 的鉴别诊断和随访提供了有力的工具，但是，这些数据需要在更大的研究中进行验证。
