3D MRI Biomarkers for Predicting Pelvic Organ Prolapse Risk and Severity

To identify 3D MRI-derived biomarkers of the cardinal ligament (CL) and uterosacral ligament (USL) for pelvic organ prolapse (POP) risk and stress urinary incontinence (SUI), and to evaluate their correlations with prolapse severity.

Female patients undergoing pelvic MRI at *** Hospital (2021-2023) were grouped into POP and control cohorts. MRI data underwent 3D reconstruction (Mimics software) and modeling (Geomagic/Solidworks) to precisely measure ligament parameters.

Women with POP had longer postmenopausal intervals, and higher parity but similar age, Body Mass Index (BMI), Lean Body Mass (LBM) and Body Surface Area (BSA). CL volume, surface area, mass, and maximal thickness were significantly reduced in POP (all $p<0.001$ ); USL metrics did not differ. Total CL mass achieved the highest discrimination for POP (AUC 0.78; sensitivity 73%, specificity 80%). CL dimensions correlated inversely with prolapse severity and SUI ( $r=-0.368$ to -0.442; $p<0.01$ ), whereas USL metrics showed no significant correlations. Bulbospongiosus muscle thickness was included due to its potential role in urethral support and continence mechanisms. Multivariate modeling retained parity (OR 4.5), CL thickness and bulbospongiosus muscle thickness (strong protective $OR<0.01$ ), left levator ani defects (OR 0.13), and levator ani asymmetry (OR 24) as independent predictors.

3D MRI quantification of CL metrics (volume, area, mass) offers noninvasive biomarkers for POP and SUI risk prediction, unlike USL morphology. These markers improve pelvic floor failure understanding and enable early POP risk identification.