Brain SPECT Study of Detrusor Overactivity and Healthy men in Urine Withholding

The disorder of bladder storage would result in storage symptoms of lower urinary tract, such as urinary incontinence, increased daytime frequency and nocturia. And urinary incontinence has long been acknowledged to be a major health problem in the elderly and a common deficit associated with many cerebral disorders. The aim of the study is to identify the brain areas, which control the bladder storage by 99mTc-HMPAO SPECT with Neurological Statistical Image Analysis Software (NEUROSTAT). SPECT scans were performed on twenty-five patients with some storage symptoms of lower urinary tract, among which nineteen patients were with detrusor overactivity (DO) (Group II) and six patients were with normal detrusor function (Group III), and fifteen healthy volunteers (Group I). All the subjects were male and right-handed, and were scanned twice under two conditions: resting state and urine withholding state. NEUROSTAT was adopted to analyze the difference in rCBF between groups and states. The results were displayed on Z-score images at a significance threshold of P < 0.05 with correction for multiple comparisons. No region reached significant threshold in comparison of Group II and III in resting state. There were significant increases in tracer activity in bilateral inferior frontal gyri and the right middle temporal gyrus in urine withholding state as compared with resting state in Group I and III（P < 0.05 with correction for multiple comparisons, the corresponding Z value was more than 4.476 for Group I, more than 4.414 for Group III）. Among the regions, the right inferior frontal gyrus was distinctly prominent at both Z-score and the extent. In Group II, only the left middle temporal gyrus and middle frontal gyrus were activated significantly in urine withholding state as compared with resting（P < 0.05 with correction for multiple comparisons, the corresponding Z value was more than 4.35）. The study indicated that bilateral inferior frontal gyri and the right middle temporal gyrus were associated with the control of bladder storage. Especially, the right inferior frontal gyrus played a more important role in cerebral control of bladder storage, inhibiting the contraction of detrusor in urine storage.