A novel infusion-drainage device to assess lower urinary tract function in neuro-imaging.
OBJECTIVE
To evaluate the applicability and precision of a novel infusion-drainage device (IDD) for standardized filling paradigms in neuro-urology and functional magnetic resonance imaging (fMRI) studies of lower urinary tract (LUT) function/dysfunction.


METHODS
The IDD is based on electrohydrostatic actuation which was previously proven feasible in a prototype setup. The current design includes hydraulic cylinders and a motorized slider to provide force and motion. Methodological aspects have been assessed in a technical application laboratory as well as in healthy subjects (n=33) and patients with LUT dysfunction (n=3) undergoing fMRI during bladder stimulation. After catheterization, the bladder was pre-filled until a persistent desire to void was reported by each subject. The scan paradigm comprised automated, repetitive bladder filling and withdrawal of 100 mL body warm (37 °C) saline, interleaved with rest and sensation rating. Neuroimaging data were analysed using Statistical Parametric Mapping version 12 (SMP12).


RESULTS
Volume delivery accuracy was between 99.1±1.2% and 99.9±0.2%, for different flow rates and volumes. Magnetic resonance (MR) compatibility was demonstrated by a small decrease in signal-to-noise ratio (SNR), i.e. 1.13% for anatomical and 0.54% for functional scans, and a decrease of 1.76% for time-variant SNR. Automated, repetitive bladder-filling elicited robust (P = 0.05, family-wise error corrected) brain activity in areas previously reported to be involved in supraspinal LUT control. There was a high synchronism between the LUT stimulation and the blood oxygenation level-dependent (BOLD) signal changes in such areas.


CONCLUSIONS
We were able to develop an MR-compatible and MR-synchronized IDD to routinely stimulate the LUT during fMRI in a standardized manner. The device provides LUT stimulation at high system accuracy resulting in significant supraspinal BOLD signal changes in interoceptive and LUT control areas in synchronicity to the applied stimuli. The IDD is commercially available, portable and multi-configurable. Such a device may help to improve precision and standardization of LUT tasks in neuro-imaging studies on supraspinal LUT control, and may therefore facilitate multi-site studies and comparability between different LUT investigations in the future.
Neuro-Urology, Spinal Cord Injury Centre & Research, University of Zürich, Balgrist University Hospital, Zürich, Switzerland.|Department of Urology, University Hospital Basel, Basel, Switzerland.
Lorenz
L
Leitner
Neuro-Urology, Spinal Cord Injury Centre & Research, University of Zürich, Balgrist University Hospital, Zürich, Switzerland.
Matthias
M
Walter
Department of Neuroradiology, University Hospital Zürich, Zürich, Switzerland.|UCLA Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA, USA.
Behnaz
B
Jarrahi
Neuro-Urology, Spinal Cord Injury Centre & Research, University of Zürich, Balgrist University Hospital, Zürich, Switzerland.
Johann
J
Wanek
Aroflex AG, Märstetten, Switzerland.
Jörg
J
Diefenbacher
Department of Neuroradiology, University Hospital Zürich, Zürich, Switzerland.
Lars
L
Michels
Department of Brain Repair and Rehabilitation, Institute of Neurology, University College London, London, UK.
Martina D
MD
Liechti
Department of Neuroradiology, University Hospital Zürich, Zürich, Switzerland.
Spyros S
SS
Kollias
Neuro-Urology, Spinal Cord Injury Centre & Research, University of Zürich, Balgrist University Hospital, Zürich, Switzerland.
Thomas M
TM
Kessler
Neuro-Urology, Spinal Cord Injury Centre & Research, University of Zürich, Balgrist University Hospital, Zürich, Switzerland.
Ulrich
U
Mehnert
D000328:Adult; D003950:Diagnostic Techniques, Urological / Q000295:instrumentation*; D004322:Drainage / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D001743:Urinary Bladder / Q000000981:diagnostic imaging* / Q000503:physiopathology*
bladder filling; functional magnetic resonance imaging (fMRI); interoception; lower urinary tract; magnetic resonance compatibility; visceral stimulation