title: The potential utility of non-invasive imaging to monitor restoration of bladder structure and function following subtotal cystectomy (STC).
abstract: BACKGROUND
  Restoration of normal bladder volume and function (i.e., bioequivalent bladder) are observed within 8 weeks of performing subtotal cystectomy (STC; removal of ~70 % of the bladder) in 12-week old rats. For analysis of bladder function in rodents, terminal urodynamic approaches are largely utilized. In the current study, we investigated the potential for Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scans to noninvasively track restoration of structure and function following STC.
  
  
  METHODS
  Twelve week old female Fisher F344 rats underwent STC and were scanned via CT and/or MRI 2, 4, 8, and 12 weeks post-STC, followed by urodynamic testing. After euthanasia, bladders were excised for histological processing.
  
  
  RESULTS
  MRI scans demonstrated an initial decline followed by a time-dependent increase to normal bladder wall thickness (BWT) by 8 weeks post-STC. Masson's trichrome staining showed a lack of fibrosis post-STC, and also revealed that the percent of smooth muscle in the bladder wall at 2 and 4 weeks positively correlated with pre-operative baseline BWT. Moreover, increased BWT values before STC was predictive of improved bladder compliance at 2 and 4 weeks post-STC. Cystometric studies indicated that repeated MRI manipulation (i.e. bladder emptying) apparently had a negative impact on bladder capacity and compliance. A "window" of bladder volumes was identified 2 weeks post-STC via CT scanning that were commensurate with normal micturition pressures measured in the same animal 6 weeks later.
  
  
  CONCLUSIONS
  Taken together, the data indicate some limitations of "non-invasive" imaging to provide insight into bladder regeneration. Specifically, mechanical manipulation of the bladder during MRI appears to negatively impact the regenerative process per se, which highlights the importance of terminal cystometric studies.
authors.affiliation: Wake Forest Institute for Regenerative Medicine, 391 Technology Way, Winston-Salem, NC, 27101, USA. david.m.burmeister3.vol@mail.mil.
authors.forename: David
authors.initials: D
authors.lastname: Burmeister
authors.affiliation: Wake Forest Institute for Regenerative Medicine, 391 Technology Way, Winston-Salem, NC, 27101, USA. bimjhanabishwokarma@fas.harvard.edu.
authors.forename: Bimjhana
authors.initials: B
authors.lastname: Bishwokarma
authors.affiliation: Wake Forest Institute for Regenerative Medicine, 391 Technology Way, Winston-Salem, NC, 27101, USA. tameraboushwareb@gmail.com.
authors.forename: Tamer
authors.initials: T
authors.lastname: AbouShwareb
authors.affiliation: Wake Forest Department of Biomolecular Imaging, Medical Center Blvd, Winston-Salem, NC, 27157, USA. jdolson3@earthlink.net.
authors.forename: John
authors.initials: J
authors.lastname: Olson
authors.affiliation: Wake Forest Institute for Regenerative Medicine, 391 Technology Way, Winston-Salem, NC, 27101, USA. hercom11@students.ecu.edu.
authors.forename: Maja
authors.initials: M
authors.lastname: Herco
authors.affiliation: Wake Forest Department of Biomolecular Imaging, Medical Center Blvd, Winston-Salem, NC, 27157, USA. jtan@wakehealth.edu.
authors.forename: Josh
authors.initials: J
authors.lastname: Tan
authors.affiliation: Wake Forest Institute for Regenerative Medicine, 391 Technology Way, Winston-Salem, NC, 27101, USA. kea@aias.au.dk.
authors.forename: Karl-Erik
authors.initials: KE
authors.lastname: Andersson
authors.affiliation: Wake Forest Institute for Regenerative Medicine, 391 Technology Way, Winston-Salem, NC, 27101, USA. gjc8w@virginia.edu.|Departments of Biomedical Engineering and Orthopaedic Surgery, and Laboratory of Regenerative Therapeutics, University of Virginia, 415 Lane Road, Charlottesville, VA, 22908, USA. gjc8w@virginia.edu.
authors.forename: George
authors.initials: G
authors.lastname: Christ
mesh_terms: D000818:Animals; D015653:Cystectomy / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D012038:Regeneration / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods*; D001743:Urinary Bladder / Q000033:anatomy & histology / Q000502:physiology* / Q000601:surgery*