Feasibility of neurite oriented diffusion and density imaging in thigh skeletal muscle of volunteers with knee pain: relationship with proton density fat fraction: a cross-sectional study

OBJECTIVES: To evaluate the microstructure changes in thigh skeletal muscles of volunteers with knee pain and to explore their relationship with the proton density fat fraction (PDFF), utilizing neurite oriented diffusion and density imaging (NODDI). MATERIALS AND METHODS: In this prospective study, we collected NODDI and mDIXON-quant images from the bilateral thigh skeletal muscles of 66 asymptomatic and 24 knee pain volunteers. To optimally match the raw data based on these variables and create asymptomatic group (HC, n = 24) and knee pain group (KP, n = 24), the MatchIt package was utilized. STATISTICAL TESTS: For the comparison of normally distributed data between the HC and KP groups, t-tests were utilized, while the Wilcoxon rank-sum test was applied for non-normally distributed data. Pearson coefficient was used to analyze the correlation between microstructure parameters of thigh skeletal muscle and PDFF. RESULTS: Statistically significant differences were observed in MD value of the left hamstrings between the HC and KP groups (p = 0.030), as well as in the FA value of the right quadriceps femoris (p = 0.026). Among volunteers experiencing knee pain, the V-intra value of the right hamstrings and the FA value of the right quadriceps femoris demonstrated a moderate positive correlation with PDFF (r = 0.661, p < 0.001; r = 0.724, p < 0.001). CONCLUSION: Microstructure differences in thigh skeletal myofibrils were detected in volunteers with knee pain compared to asymptomatic volunteers, and were more closely related to intramuscular fat infiltration.