Evaluation of cortical activity associated with filling of urinary bladder using functional magnetic resonance imaging
Abstract
The aim of the study was to assess: 1. the feasibility of a novel method combining functional magnetic resonance imaging (fMrI) evaluation of the central nervous system with synchronously performed filling cystometry, 2. fMrI evaluation of brain cortical activity associated with filling of the urinary bladder. Methods: Aurodynamic system was adapted to enable synchronous filling cystometry with fMrI.
Fourteen female volunteers with no urological disorder (20-68 yrs) were enrolled. Standard filling cystometry protocol was extended to strengthen the afferent sensory signal: the sensory activation was elicited by cyclic phases of filling and emptying.
Synchronously with extended cystometry, cortical activity was evaluated using fMrI. To yield representative data, we repeated each examination after 4-6 weeks having 28 data sets for analysis at the end.
All examinations were performed on 3T scanner using gradient-echo ePI sequence. Results: Adjustments of the urodynamic system enabled successful implementation of synchronous filling cystometry with fMrI evaluation of cortical activity.
All urodynamic records presented normal findings. Twenty four data sets were evaluated by an independent component analysis.
The fMrI data were interpreted considering the synchronous cystometry record. The following cortical activity was detected: middle and inferior frontal gyrus, angular gyrus, posterior and anterior cingulate gyrus and subcortical grey nuclei.
Conclusion: fMrI evaluation of cortical activity associated with evaluation of the lower urinary tract function is an experimental method with a number of technical difficulties. Synchronous urodynamic examination is a feasible method that facilitates precise interpretation of fMrI data acquired.
The presented study demonstrates the activity of the central nervous system structures associated with filling of the urinary bladder.