Noninvasive technique to evaluate the muscle fiber characteristics using q-space imaging
Noninvasive technique to evaluate the muscle fiber characteristics using q-space imaging
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DOI：
10.1371/journal.pone.0214805
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发表时间：
2019-04-04
期刊：
影响因子：
3.7
通讯作者：
Nakamura, Masaya
中科院分区：
文献类型：
--
作者：
Hata, Junichi;Nakashima, Daisuke;Nakamura, Masaya
背景骨骼肌包括快肌纤维和慢肌纤维。胫前肌(TA)主要由快肌纤维组成，而比目鱼肌(SOL)主要由慢肌纤维组成。然而，没有一种非侵入性的方法可以适当地研究肌肉的特征。监测骨骼肌特性有助于评估力量训练和疾病对骨骼肌的影响。目的本研究旨在探讨Q空间成像在小鼠体内能否区分TA和SOL。方法采用7-Tesla磁共振成像系统和低温探头对8只小鼠右小腿进行磁共振成像。对TA和SOL进行评估。Q空间成像，视野10 mm×10 mm，矩阵48×48，层厚1000µm，有10个b值，范围为0~4244 S/mm(2)，每个b值均有三个方向的扩散编码。结果Q空间成像的半峰全宽和峰度图显示快肌纤维(肌球蛋白重链II)和慢肌纤维(肌球蛋白重链I)的信号强度与免疫组织学结果一致。在定量方面，半峰全宽和峰度均可代表TA的细胞直径大于SOL的免疫组织学结果(P<；0.01)。结论q空间成像可以根据细胞直径的不同而清楚地区分TA和SOL。这项技术是一种很有前途的无创估计骨骼肌纤维类型比率的方法，它可以进一步发展成为肌肉特性的指标。
BackgroundSkeletal muscles include fast and slow muscle fibers. The tibialis anterior muscle (TA) is mainly composed of fast muscle fibers, whereas the soleus muscle (SOL) is mainly composed of slow muscle fibers. However, a noninvasive approach for appropriately investigating the characteristics of muscles is not available. Monitoring of skeletal muscle characteristics can help in the evaluation of the effects of strength training and diseases on skeletal muscles.PurposeThe present study aimed to determine whether q-space imaging can distinguish between TA and SOL in in vivo mice.MethodsIn vivo magnetic resonance imaging of the right calves of mice (n = 8) was performed using a 7-Tesla magnetic resonance imaging system with a cryogenic probe. TA and SOL were assessed. q-space imaging was performed with a field of view of 10 mm x 10 mm, matrix of 48 x 48, and section thickness of 1000 mu m. There were ten b-values ranging from 0 to 4244 s/mm(2), and each b-value had diffusion encoding in three directions. Magnetic resonance imaging findings were compared with immunohistological findings.ResultsFull width at half maximum and Kurtosis maps of q-space imaging showed signal intensities consistent with immunohistological findings for both fast (myosin heavy chain II) and slow (myosin heavy chain I) muscle fibers. With regard to quantification, both full width at half maximum and Kurtosis could represent the immunohistological findings that the cell diameter of TA was larger than that of SOL (P < 0.01).Conclusionq-space imaging could clearly differentiate TA from SOL using differences in cell diameters. This technique is a promising method to noninvasively estimate the fiber type ratio in skeletal muscles, and it can be further developed as an indicator of muscle characteristics.