Multiparametric Pelvic-Floor Magnetic Resonance Imaging for the Staging of Anterior-Compartment Clinical Pelvic Organ Prolapse: A Prospective Study

Objective: This study aimed to evaluate the utility of multiparametric pelvic-floor magnetic resonance imaging (MRI) for identifying stage III–IV anterior-compartment clinical pelvic organ prolapse (POP) and guiding clinical management. Methods: In total, 123 women with confirmed anterior-compartment clinical POP were prospectively categorized into non-stage III–IV (n = 60) and stage III–IV (n = 63) groups. All participants underwent combined pelvic-floor static –dynamic MRI and T2 star (T2*) mapping. Levator ani muscle (LAM) injury was assessed. The perpendicular distance from the bladder base to the pubococcygeal line (B-PCL), H-line, M-line, levator hiatus area (LHA), levator plate angle, and iliococcygeal angle were measured at rest and maximum Valsalva. T2* values were measured in LAM. Univariate and logistic regression analyses were used to diagnose stage III–IV prolapse. The optimal model was compared with the conventional MRI-based “rule of three”. Results: Compared with the non-stage III–IV group, the stage III–IV group was significantly older in age; had higher Pelvic Floor Distress Inventory-20 scores; exhibited larger B-PCL, M-line, and LHA values at maximum Valsalva; and demonstrated lower pubovisceral muscle T2* values. Compared with the “rule of three”, the optimal multiparametric MRI-based model achieved an area under the curve of 0.802, with significantly higher sensitivity, modestly lower specificity, and superior overall accuracy. Conclusion: The multiparametric pelvic-floor MRI-based diagnostic model demonstrates superior performance in identifying stage III–IV anterior-compartment clinical POP. This model provides an objective imaging-based reference to support accurate POP staging and guide clinical management. Keywords: pelvic organ prolapse, magnetic resonance imaging, T2* mapping, diagnostic imaging, pelvic floor