Localization and quantification of intramuscular damage using statistical parametric mapping and skeletal muscle parcellation

Abstract

In the present study, we proposed an original and robust methodology which combines the spatial normalization of skeletal muscle images, the statistical parametric mapping (SPM) analysis and the use of a specific parcellation in order to accurately localize and quantify the extent of skeletal muscle damage within the four heads of the quadriceps femoris. T2 maps of thigh muscles were characterized before, two (D2) and four (D4) days after 40 maximal isometric electrically-evoked contractions in 25 healthy young males. On the basis of SPM analysis of coregistrated T2 maps, the alterations were similarly detected at D2 and D4 in the superficial and distal regions of the vastus medialis (VM) whereas the proportion of altered muscle was higher in deep muscle regions of the vastus lateralis at D4 (deep: 35 ± 25%, superficial: 23 ± 15%) as compared to D2 (deep: 18 ± 13%, superficial: 17 ± 13%). The present methodology used for the first time on skeletal muscle would be of utmost interest to detect subtle intramuscular alterations not only for the diagnosis of muscular diseases but also for assessing the efficacy of potential therapeutic interventions and clinical treatment strategies.

Spatial difference can occur between activated and damaged muscle areas following electrically‐induced isometric contractions

“…On the contrary, regarding the VL muscle, activated and damaged areas were spatially different thereby suggesting that intramuscular shear stress could be the accounting factor of the damage occurring during the NMES session as previously suggested (Fouré et al . ,b). In other words, tissues other than active muscle fibres such as connective tissues and/or intracellular structural elements such as costameres could be altered during damaging contractions (Crameri et al .…”

“…As previously described (Fouré et al . ), a multi‐step method was performed for intra‐ and inter‐subject normalizations using Advanced Normalization Tools (ANTs library). Both intra‐ and inter‐subject normalizations were partly based on anatomical landmarks manually selected on T 1 ‐weighted images.…”

“…Surprisingly, T 2 increases in muscles directly located beneath the stimulation electrodes were reported as muscle‐specific for knee extensors (Fouré et al . ) and localized in the superficial part of the vastus medialis (VM) and the deep part of the vastus lateralis (VL).…”

“…T 2 mapping performed immediately and within days after NMES might provide key information as long as the issue of 3‐D co‐registration of magnetic resonance (MR) images can be addressed (Fouré et al . , ).…”

Fast measurement of the quadriceps femoris muscle transverse relaxation time at high magnetic field using segmented echo-planar imaging

“…It is well established that the profile (endurance/explosive) and/or the training status of the volunteers (from recreationally active volunteers performing an unaccustomed exercise to volunteers trained in endurance exercises) can contribute to the interindividual difference in relative contribution of the QF muscle during an exercise performed at 60% MVC . In that way, the combination of sSE‐EPI sequence with a newly developed methodology based on statistical parametric mapping would allow accurately localizing muscle activation according to the muscle contraction modality ( e.g. voluntary vs. electrically evoked or concentric vs. eccentric).…”