Static and Dynamic MRI Combined with DTI in Evaluation Anatomy and Function of Levator Ani Muscles in Pelvic Organ Prolapse Women

Objective To evaluate the morphological and functional changes of levator ani muscles in women with pelvic organ prolapse(POP) using static,dynamic magnetic resonance(MR) imaging and diffusion tensor imaging(DTI).Methods Forty one women with POP(POP group) and 30 normal women(control group) were collected in the study.The morphology of levator ani muscles were measured on static MR imaging.Dynamic MR imaging was usedto evaluate functional abnormalities and to record.five measurements of supporting structures.DTI was used to determine fractional anisotropy(FA) changes.Results The levator hiatus showed enlarged as "O"shape in 12(29.3%) of 41 POP patients on static MR imaging and in 41 cases(100%) on dynamic MR imaging.Iliococcygeal muscle was showed as funnel-shape in 29 cases(70.7%)on static MR imaging,and basin shape in 34 cases(82.9%) on dynamic MR imaging.Atrophy or rupture of levator ani muscles were showed in 22 cases(53.7%).H line,M line and levator hiatus width of POP patients were bigger than that of controls on static MR imaging(P0.05).Levator plate angle(LPA),H line,M line and levator hiatus width of POP patients were bigger than that of controls on dynamic MR imaging(P0.05).Conclusion POP was associated with levator ani defects,decreased support function and pelvic floor laxity.Combined analysis of static,dynamic MR imaging and DTI allows identification of certain morphological abnormalities with specific dysfunction.