title: Test-retest repeatability of patterns of brain activation provoked by bladder filling.
abstract: OBJECTIVE
  To assess short-term repeatability of an fMRI protocol widely used to assess brain control of the bladder. fMRI offers the potential to discern incontinence phenotypes as well as the mechanisms mediating therapeutic response. If so, this could enable more targeted efforts to enhance therapy. Such data, however, require excellent test-retest repeatability.
  
  
  METHODS
  Fifty-nine older women (age ≥60 years) with urgency incontinence underwent two fMRI scans within 5-10 min with a concurrent bladder infusion/withdrawal protocol. Activity in three brain regions relevant to bladder control was compared using paired t tests and intra-class correlation.
  
  
  RESULTS
  There were no statistically significant differences in brain activity between the two consecutive scans in the regions of interest. Intra-class correlation was 0.19 in the right insula, 0.32 in the dorsal anterior cingulate cortex/supplementary motor area, and 0.44 in the medial pre-frontal cortex. Such correlations are considered fair or poor, but are comparable to those from studies of other repeated fMRI tasks.
  
  
  CONCLUSIONS
  This is the first evaluation of the repeatability of a bladder fMRI protocol. The technique used provides a framework for comparing different fMRI protocols applied to brain-bladder research. Despite universal patient response to the stimulus, brain response had limited repeatability within individuals. Improvement of the investigational protocol should magnify brain response and reduce variability. These results suggest that although analysis of fMRI data among groups of subjects yields valuable insight into bladder control, fMRI is not yet appropriate for evaluation of the brain's role in continence on an individual level.
authors: Division of Geriatric Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors: Becky D
authors: BD
authors: Clarkson
authors: Division of Geriatric Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors: Shachi
authors: S
authors: Tyagi
authors: Division of Geriatric Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors: Derek J
authors: DJ
authors: Griffiths
authors: Division of Geriatric Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors: Neil M
authors: NM
authors: Resnick
mesh_terms: D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging* / Q000502:physiology; D001931:Brain Mapping / Q000379:methods; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D015203:Reproducibility of Results; D001743:Urinary Bladder / Q000502:physiology*
keywords: fMRI; neuroimaging; reproducibility of results; test-retest reliability; urge; urinary incontinence; women