title: Positional pelvic organ prolapse (POP) evaluation using open, weight-bearing magnetic resonance imaging (MRI).
abstract: BACKGROUND
  Magnetic resonance imaging (MRI) of patients with pelvic organ prolapse (POP) is completed in the supine position. Open magnetic resonance imaging (MRO) uses vertical magnets, allowing imaging in a variety of upright postures. This pilot study used MRO to evaluate the change of prolapse in different positions compared to non-prolapsed images.
  
  
  METHODS
  In total, 11 women (6 POP, 5 controls) aged 24 to 65 years had 12 MRO images (midline sagittal pelvic line) consecutively when supine, sitting and standing with a full and empty bladder. Lengths between the lowest point of the bladder to the pubococcygeal (PC) and pubopromontoreal (PP) lines in each image were compared, and the ratio of bladder area under the PC and PP lines to the total bladder area.
  
  
  RESULTS
  Significant elongation between the PC line and lowest point of the bladder was evident in subjects with POP comparing supine and standing images (p = 0.03), but not controls (p = 0.07). Similarly, this axis was significantly longer in cystocele subjects versus controls only in the standing position. Bladder area under the PC line was significantly increased between supine and standing positions only among subjects with cystocele (p < 0.01), and significantly larger among the study group in the standing position (p < 0.005), less significant in the supine position (p = 0.015), and not significant in the sitting position (p = 0.3).
  
  
  CONCLUSIONS
  MRO imaging allows us to investigate the effects of upright position and weight bearing on the staging of POP. Imaging patients when sitting and standing identified that significant changes occur in the maximal descent of the bladder.
authors.affiliation: Associate Member, Department of Urology, Lady Davis Carmel medical center, Technion Institute of Technology, Haifa, Israel;
authors.forename: Boris
authors.initials: B
authors.lastname: Friedman
authors.affiliation: Department of Urologic Sciences University of British Columbia, Canada;
authors.forename: Lynn
authors.initials: L
authors.lastname: Stothers
authors.affiliation: Clinical Assistant Professor, Division of Specialty Gynaecology, Dept. of Obstetrics and Gynaecology, University of British Columbia, Canada.
authors.forename: Darren
authors.initials: D
authors.lastname: Lazare
authors.affiliation: Department of Urologic Sciences University of British Columbia, Canada;
authors.forename: Andrew
authors.initials: A
authors.lastname: Macnab