Noninvasive technique to evaluate the muscle fiber characteristics using q-space imaging

Abstract

Background Skeletal 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. Purpose The present study aimed to determine whether q-space imaging can distinguish between TA and SOL in in vivo mice. Methods In 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 × 10 mm, matrix of 48 × 48, and section thickness of 1000 μm. 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. Results Full 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). Conclusion q-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.

Assessing the variability of 23Na MRI in skeletal muscle tissue: Reproducibility and repeatability of tissue sodium concentration measurements in the lower leg at 3 T

“…26,27 For example, muscle cells in tibialis anterior can exhibit a larger diameter than those of soleus muscle. 28 The phantom measurements showed that B 0 correction could partially improve the quantitative accuracy and reproducibility between the two different sites. Thus we performed B 0 correction for the in vivo data.…”

Laurel Attenuates Dexamethasone-Induced Skeletal Muscle Atrophy In Vitro and in a Rat Model

“…As body weight loss observed after DEX treatment is primarily attributable to skeletal muscle atrophy [ 30 ], the reduction in body weight and the associated reduction in gastrocnemius and tibialis anterior mass found in our DEX-treated rats were not incomprehensible. Gastrocnemius and tibialis anterior are skeletal muscles with relatively more fast-twitch fibers and fewer slow-twitch fibers, whereas the soleus is the opposite [ 31 , 32 ]. DEX has been shown to act primarily on muscles that contain type IIb fast-twitch fibers [ 33 ].…”

“…In this study, muscle atrophy was observed only in gastrocnemius and tibialis anterior, which may be associated with increased expression of atrogin-1/MAFbx and MuRF1, but not in soleus, which is consistent with previous findings [ 33 ]. Although the weight of the extensor digitorum longus tended to decrease in the DEX group compared with the control group, the extensor digitorum longus is a smaller muscle that lies deeper than gastrocnemius and tibialis anterior muscles, and the difference was difficult to identify after DEX-induced muscle atrophy [ 31 , 33 ]. Based on the previous research and our findings, we suggest that DEX-induced fast-twitch muscle atrophy may be associated with increased expression of atrogin-1/MAFbx and MuRF1.…”

MRI in the assessment of adipose tissues and muscle composition: how to use it

“…In fact, the non-specificity of muscular T1 and T2 times limits the ability to reproducibly determine fiber type composition in clinical routine. More recent investigations have however presented encouraging approaches utilizing quantitative methods of diffusion-weighted MR (q-space imaging) and were able to differentiate different muscles (by their fiber composition) in mice (33).…”