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Abstract

Background: Weakness or damage to the pelvic floor muscles results in pelvic organ prolapse (POP), which affects 50% of women >50 years old. Posture and gravity impact organ position and symptom severity. Current limitations of clinical examination and restriction to imaging in the supine position impact accurate diagnosis and disease staging. Open upright magnetic resonance imaging (MRO), allows images of patients sitting, standing, and supine. In this dissertation it is hypothesized that MRO images will allow improved detection of the presence and extent of prolapse. Methods: A Paramed Medical Systems 0.5 T upright Open MRI scanner (MRO) was used to obtain axial and sagittal T2-weighted pelvic scans in women when supine, sitting, and standing. Symptomatic women with POP and asymptomatic controls were studied. The protocol developed obtains good quality images efficiently in all three positions. Validated reference lines were used to identify where POP was present in the same patient in different positions and to grade its severity. A manual segmentation methodology was developed using Analyze 12.0 software to construct 3D models of the female pelvis from 2D images to enhance the visualization of complex pelvic anatomy. Results: Forty women (20 with POP and 20 asymptomatic controls) were studied. Detection of POP in standing versus supine images in symptomatic women was 50% vs. 5% for cystocele and 35% vs. 25% for vaginal prolapse, indicating improved visualization of gravity-dependent POP with MRO standing imaging. Image comparison indicated that the extent of prolapse is best evaluated in the standing position using the pubococcygeal reference line. These images better identify downward movement in the anterior and posterior compartments. No appreciable benefit was afforded by seated images. Conclusion: The findings support the hypothesis that MRO imaging of POP patients is relevant to improving the detection and quantification of POP. The MRO protocol developed for standing images in women with POP demonstrated feasibility allowing supine, sitting, and standing imaging of changes in pelvic floor anatomy in upright positioning. When compared with supine images, standing images better identify the presence and extent of POP. 3D image modeling allows more comprehensive visualization of complex female pelvic anatomy.