Multimodal MRI assessment of levator ani function in women: Comparison with the Modified Oxford Scale.

INTRODUCTION: This study aimed to establish a more comprehensive and precise method for assessing levator ani muscle (LAM) strength in women by examining the correlation of LAM width, the three-dimensional fat analysis calculation technique (3D-FACT), and intravoxel incoherent motion (IVIM) parameters with Modified Oxford Scale (MOS) grade. METHODS: Baseline characteristics, MOS grades and multimodal magnetic resonance imaging (MRI) data were collected in this retrospective study of 326 female participants. Participants were grouped by MOS grade, and compared using appropriate parametric or non-parametric tests. Correlations between MRI parameters and MOS grade were assessed using Pearson or Spearman coefficients and partial correlation analysis, adjusting for confounders. RESULTS: LAM width, proton density fat fraction (PDFF), transverse relaxation rate (R2*), slow diffusion coefficient (D), and perfusion fraction (f) differed significantly between MOS-based strength groups, while a significant difference in the fast diffusion coefficient (D*) was isolated to the iliococcygeus muscle. MOS grade was positively correlated with levator ani width and D values, and inversely correlated with PDFF and R2*. DISCUSSION: This study demonstrates that quantitative MRI parameters (LAM width, D, PDFF, R2*), showing correlation with MOS grade, serve as valuable biomarkers for assessing LAM function in women. CONCLUSION: Multimodal MRI with 3D-FACT and IVIM shows potential for assessing LAM function in females.