Department of Radiology, Wonju Severance Christian Hospital, Wonju College of Medicine, Yonsei University of Korea, Wonju 26426, Republic of Korea.
Department of Rehabilitation Medicine, Wonju Severance Christian Hospital, Wonju College of Medicine, Yonsei University of Korea, Wonju 26426, Republic of Korea.
Tomography. 2024 Mar 1;10(3):368-377. doi: 10.3390/tomography10030029.
(1) Background: The intravoxel incoherent motion (IVIM) model can provide information about both molecular diffusion and blood flow for the evaluation of skeletal muscle inflammation. MRI-based fat quantification is advantageous for assessing fat infiltration in skeletal muscle. (2) Purpose: We aimed to quantitatively measure various parameters associated with IVIM diffusion-weighted imaging (DWI) and fat quantification in the muscles of patients with polymyositis and dermatomyositis using magnetic resonance imaging and to investigate the relationship between these parameters and electromyography (EMG) findings. (3) Material and methods: Data were retrospectively evaluated for 12 patients with polymyositis and dermatomyositis who underwent thigh MRI, including IVIM-DWI and fat quantification. The IVIM-derived parameters included the pure diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (). Fat fraction values were assessed using the six-point Dixon technique. Needle EMG was performed within 9 days of the MRI. (4) Results: The values (19.02 ± 4.87%) in muscles with pathological spontaneous activity on EMG were significantly higher than those (14.60 ± 5.31) in muscles without pathological spontaneous activity ( < 0.027). There were no significant differences in D, D*, ADC, or fat fraction between muscles with and without pathologic spontaneous activity. Significant negative correlations were observed between fat fraction and amplitude ( = -0.402, < 0.015) and between fat fraction and duration ( = -0.360, < 0.031). (5) Conclusion: The current study demonstrates that IVIM-DWI and fat quantification using 3.0 T MRI may aid in predicting EMG findings in patients with polymyositis and dermatomyositis and promote the pathophysiological study of idiopathic inflammatory myopathies.
（1）背景：体素内不相干运动（IVIM）模型可提供评估骨骼肌炎症的分子扩散和血流信息。基于 MRI 的脂肪定量有利于评估骨骼肌脂肪浸润。（2）目的：我们旨在使用磁共振成像定量测量多发性肌炎和皮肌炎患者肌肉中与 IVIM 扩散加权成像（DWI）和脂肪定量相关的各种参数，并研究这些参数与肌电图（EMG）发现之间的关系。（3）材料和方法：回顾性评估了 12 例接受大腿 MRI 检查的多发性肌炎和皮肌炎患者的数据，包括 IVIM-DWI 和脂肪定量。IVIM 衍生参数包括纯扩散系数（D）、假性扩散系数（D*）和灌注分数（）。脂肪分数值采用六点 Dixon 技术评估。MRI 后 9 天内进行针状 EMG。（4）结果：在 EMG 上具有病理性自发性活动的肌肉中的值（19.02±4.87%）明显高于在没有病理性自发性活动的肌肉中的值（14.60±5.31%）（<0.027）。具有和不具有病理性自发性活动的肌肉之间的 D、D*、ADC 或脂肪分数没有显著差异。脂肪分数与振幅呈显著负相关（= -0.402，<0.015），脂肪分数与持续时间呈显著负相关（= -0.360，<0.031）。（5）结论：本研究表明，使用 3.0T MRI 的 IVIM-DWI 和脂肪定量可能有助于预测多发性肌炎和皮肌炎患者的 EMG 发现，并促进特发性炎症性肌病的病理生理学研究。
