Heskamp Linda, Schlaffke Lara, Forsting Johannes, Sleutjes Boudewijn T H M, Goedee H Stephan, Froeling Martijn
Center for Image Sciences, Precision Imaging Group, Division Imaging & Oncology, University Medical Centre Utrecht, Utrecht, The Netherlands.
Department of Neurology, BG-University Hospital Bergmannsheil gGmbH, Bochum, Germany.
Physiol Rep. 2025 Mar;13(6):e70247. doi: 10.14814/phy2.70247.
Fasciculations, a hallmark of motor neuron diseases, also occur in healthy individuals, highlighting the need to understand fasciculation intensity and distribution. Motor unit MRI (MUMRI) can assess fasciculations in large volumes but is not widely applied. We hypothesize that a more common MRI technique, diffusion tensor imaging (DTI), can also detect fasciculation when correcting for low signal-to-noise ratios and signal variability. We first systematically compared MUMRI and DTI in upper leg muscles of healthy subjects (n = 5). Secondly, we retrospectively determined fasciculation intensity and distribution in lower extremity muscles of 30 healthy subjects using DTI (n = 30). DTI and MUMRI had comparable sensitivity (75%) and precision (80%) to expert reviews. In our healthy cohort, fasciculations were more prevalent in the lower legs than upper legs (13.9 ± 11.5% vs. 9.8 ± 6.3%, p = 0.011), particularly in the soleus (9.3 ± 8.1%). This effect persisted after normalizing for muscle volume (7.2 ± 5.1%/dm vs. 2.9 ± 1.8%/dm, p < 0.001). Lower leg fasciculations were larger compared to upper leg fasciculations (0.81 ± 0.31 cm vs. 0.54 ± 0.15 cm, p < 0.001). Longitudinal analysis showed consistent fasciculation distribution over 8 months (n = 13, ICC = 0.803). In conclusion, muscle DTI detects fasciculations in all lower extremity muscles, enabling retrospective analysis of existing datasets and reducing the need for prospective MUMRI studies if muscle DTI is already acquired.
肌束震颤是运动神经元疾病的一个标志，也会出现在健康个体中，这凸显了了解肌束震颤强度和分布的必要性。运动单元磁共振成像（MUMRI）可以评估大面积的肌束震颤，但尚未得到广泛应用。我们推测，一种更常用的磁共振成像技术——扩散张量成像（DTI），在纠正低信噪比和信号变异性后，也能够检测到肌束震颤。我们首先系统地比较了健康受试者（n = 5）大腿肌肉中的MUMRI和DTI。其次，我们回顾性地使用DTI确定了30名健康受试者下肢肌肉的肌束震颤强度和分布（n = 30）。DTI和MUMRI在敏感性（75%）和精确度（80%）方面与专家评估结果相当。在我们的健康队列中，小腿的肌束震颤比大腿更普遍（13.9±11.5%对9.8±6.3%，p = 0.011），尤其是比目鱼肌（9.3±8.1%）。在对肌肉体积进行归一化后，这种效应仍然存在（7.2±5.1%/dm对2.9±1.8%/dm，p < 0.001）。与大腿的肌束震颤相比，小腿的肌束震颤更大（0.81±0.31厘米对0.54±0.15厘米，p < 0.001）。纵向分析显示，在8个月内肌束震颤分布一致（n = 13，组内相关系数 = 0.803）。总之，肌肉DTI能够检测到所有下肢肌肉的肌束震颤，从而能够对现有数据集进行回顾性分析，并且如果已经获取了肌肉DTI数据，则无需进行前瞻性MUMRI研究。
