Magnetic Resonance Imaging of the Pelvic Floor Muscle Morphology in Women with Stress Urinary

Park, Yan Il; Kim, Kang Won; Min, Kyung Dae; Gwon, Dong Deuk; Jung, Yong Yeon

Abstract

This study was designed to define static and dynamic magnetic resonance imaging (MRI) appearance of changes in bladder neck and levator ani muscle, and find out clinical significance of this method compared with valsalva leak point pressure (VLPP) in patients with stress urinary incontinence. Thirteen patients were studied with supine static MR imaging through axial and sagittal pelvic imaging in the first and second procedures and then were examined with dynamic MR imaging through static and then dynamic midline sagittal imaging in the third procedure. We evaluated the changes in bladder neck and levator ani muscle of stress urinary incontinece patients from these MR imaging. Patients were divided into two groups according to their responses to VLPP; the group 1 (n=8) with VLPP below 60 cmH2O and the group 2 (n=5) with VLPP above 60 cmH2O. We analyzed the data taken comparing MR imaging results with VLPP results. On supine static and dynamic MRI, there were beak shaped changes in the bladder neck in 5 patients (62.5%) of group 1, 1 patients (20%) of group 2 and funnel shaped change or non-specific changes in the rest cases of group 2. The degenerative changes of leveator ani muscle were observed in 4 patients (50%) from group 1. But we could not observe patients (0%) from group 2. Supine static/dynamic MRI and complementing VLPP with urodynamic study not only provide valuable support to basic concepts of the pathophysiology of stress urinary incontinence but also help to establish normal findings of female paraurethral and bladder neck anatomy.