Assessment of Brainstem Functional Organization in Healthy Adults and Overactive Bladder Patients Using Ultra-High Field fMRI

Abstract

The pathophysiological mechanisms of overactive bladder syndrome (OAB) remain largely unknown, with major involvement of the central nervous system (CNS). The periaqueductal gray (PAG) is a brainstem area which is indicated to play an essential role in bidirectional communication between the bladder and the CNS. We aimed to assess consistency of PAG functional organization across different bladder sensory states in OAB patients. We propose, that PAG functional organization patterns across sensory states will differ between controls and OAB patients. We analyzed fMRI scans at 7 Tesla from six controls and two OAB patients. The Louvain module detection algorithm was applied to parcellate the PAG in empty and full bladder states. We assessed within-subject consistency and investigated differences in this consistency between both groups. High within-subject agreement of PAG parcellations between empty and full bladder states was demonstrated in both groups. Additionally, we showed that the correlations between PAG clusters in both bladder states were significantly different in patients compared to controls (p = 0.039). The methods introduced here offer a promising tool to assess functional organization of the PAG and understand the underlying pathology and the role of this region in OAB syndrome.

Is the insomnia phenotype the common denominator in LUTS during transition periods? An expert NOPIA research group review

“…24,25 The initial results from studies following these directions indicate that consistency of functional subdivisions of the PAG between empty and full bladder states differ significantly between healthy adults and OAB patients. 26…”

“…Innovative neuroimaging approaches enable detailed investigation of central mechanisms associated with LUT sensory processing in aging 24,25 . The initial results from studies following these directions indicate that consistency of functional subdivisions of the PAG between empty and full bladder states differ significantly between healthy adults and OAB patients 26 …”

How do we make progress in phenotyping patients with lower urinary tract such as overactive bladder and underactive detrusor, including using urine markers and microbiome data, to personalize therapy? ICI‐RS 2023—Part 2

“…37 Research utilizing 7 Tesla fMRI to assess the consistency of the functional organization of the PAG between empty and full bladder states has indicated that differences can be observed between healthy adults and OAB patients. 38 Currently, the optimization of SNS stimulation paradigms relies on observing motor responses associated with stimulation of the sacral nerves. However, it is probable that the therapeutic response predominantly arises from the stimulation of sensory nerve fibers.…”

“…Neuroimaging presents a tool to improve therapeutic strategies such as SNS by measuring CNS responses associated with the stimulation of sensory sacral nerve fibers. 38 To conclude, functional neuroimaging, in particular using ultrahigh field fMRI, will be an essential tool to improve our understanding of the heterogeneity of LUTS patient phenotypes. This will improve patient characterization and diagnostic procedures and will facilitate the identification of predictive factors associated with therapeutic effectivity.…”

Developing new ways to assess neural control of pelvic organ function in spinal conditions: ICI‐RS 2023

“…34 Neuroimaging studies have unraveled functional and structural differences in the CNS between healthy adults and patients with LUT dysfunction, such as idiopathic overactive bladder syndrome (OAB). 35,36 This potentially can fine-tune diagnostic procedures, identify predictors of outcome, and enable objective assessment of responses to therapeutic interventions. Evaluation of CNS activity during manipulation of bladder sensations (using automated bladder filling via a catheter) in spinal cord injury (SCI) patients has indicated that CNS processes associated with bladder sensations are, to some extent, present in brain areas associated with vagal afferents in patients with complete lesions between C7 and T5.…”