Purpose: Urological chronic pelvic pain syndromes have refractory bladder or pelvic pain as the dominant symptom. This has been attributed to changes in the central nervous system caused by a chronic barrage of noxious stimuli. We developed what is to our knowledge a novel challenge protocol that induced bladder distention in study participants to reproduce pain and urinary symptoms. We tested to see whether it could discriminate between persons with urological chronic pelvic pain syndrome-like symptoms and asymptomatic controls.
Materials and methods: We recruited 10 female twin pairs who were discordant for urological chronic pelvic pain syndrome-like symptoms. Before scanning each twin urinated to completion and then consumed 500 cc water. Each twin was scanned with our resting state functional magnetic resonance imaging protocol immediately and approximately 50 minutes after consumption. Time series were extracted from the right and left periaqueductal gray, and the right and left amygdala subregions. We performed the repeated measures 2-sample t-test to assess differences in connectivity between symptomatic and asymptomatic twins before and after bladder distention.
Results: Group by condition interaction effects were found from the periaqueductal gray to the right cerebellum VIIIa, the amygdala, the right premotor cortex/supplementary motor area and the insular cortex, and between the amygdala and the frontal pole/medial orbital frontal cortex, the hypothalamus, the insular cortex, the thalamus and the anterior cingulate cortex.
Conclusions: These findings demonstrate that our noninvasive bladder distention protocol can detect differences in the processing of urinary sensation between twins discordant for lower urinary tract pain.
Kleinhans NM, Yang CC, Strachan ED, Buchwald DS, Maravilla KR. Alterations in Connectivity on Functional Magnetic Resonance Imaging with Provocation of Lower Urinary Tract Symptoms: A MAPP Research Network Feasibility Study of Urological Chronic Pelvic Pain Syndromes. J Urol. 2016 Mar;195(3):639-45. PMC5035686.