Magnetic Resonance Imaging and Spectroscopy to Assess Leg Muscle Macrostructure and Microstructure in Healthy Older Women: A Feasibility Assessment

Abstract Background Advanced magnetic resonance (MR) scanning techniques, such as diffusion tensor imaging (DTI) and proton MR spectroscopy ( 1 H-MRS) permit microstructural evaluation of water diffusivity and intramyocellular lipid content, respectively. We aimed to determine the feasibility of performing advanced MR scanning (proton density [PD] weighted imaging, DTI, and 1 H-MRS) to evaluate properties of leg muscles in older women with respect to: (1) participant recruitment using three community-based strategies; (2) participant tolerance to the MRI scan acquisition protocol; and (3) scan acquisition and analyses protocols. Methods Recruitment feasibility was evaluated based on the number of participants enrolled using various strategies. Participant tolerance was feasible if the scanning session was uninterrupted and image artifacts were absent. Optimal PD imaging, DTI, and 1 H-MRS acquisition and analyses protocols were established. Results Nine women (mean age=71 years) were recruited over four months. The acquisition protocol was well tolerated by all participants. Adaptations were required for women with short stature and vertebral fracture risk. PD-weighted image analyses were improved by using the phased array uniformity enhancement filter to increase tissue contrast. Conclusions It is feasible to use a combination of MR scanning methods to evaluate muscle macrostructure and microstructure in the leg of older women. Our findings suggest that advanced MR scanning methods can be used for future studies interested in quantifying components of muscle structure in older women, but prospective studies are needed to confirm whether change in microstructure can be detected in response to an intervention.