Correlation of right frontal hypoperfusion and urinary dysfunction in iNPH: A SPECT study§


  • Eric Rovner led the review process.

  • Disclosure information: None of the authors have financial support relevant to the study. All authors have no conflict of interests.

  • §

    Ethics: All patients gave informed consent before participating in the study. The present study was approved by the Ethics Committee at Sakura Medical Center, Toho University.

  • Imaging Statistical Analysis was made with a 3D-SSP software by Dr. Uchida.

  • Author Roles: Ryuji Sakakibara: Design, organization, analysis, and execution of the study. Yoshitaka Uchida: Statistical analysis of the study. Kazunari Ishii, Hiromitsu Kazui, Masaaki Hashimoto, Masaaki Ishikawa, Tatsuhiko Yuasa, Masahiko Kishi, Emina Ogawa, Fuyuki Tateno, Tomoyuki Uchiyama, Tatsuya Yamamoto, Tomonori Yamanishi, Hitoshi Terada: Execution of the study.



To elucidate the pathophysiology of urinary dysfunction in idiopathic normal-pressure hydrocephalus (iNPH) by single-photon emission computed tomography (SPECT) and statistical brain mapping.


Urinary symptoms were observed and N-isopropyl-p-[123I]-iodoamphetamine (IMP)-SPECT imaging was performed in 97 patients with clinico-radiologically definite iNPH. The patients included 56 men and 41 women; mean age, 74 years. The statistical difference in normalized mean tracer counts was calculated and visualized between patients with urinary dysfunction of severer degrees (>grade 2/4) and milder degrees (<grade 1/4) according to the urinary subscales of the iNPH grading scales.


There was a significant decrease in tracer activity in the right-side-dominant bilateral frontal cortex and the left inferior temporal gyrus in the severe urinary dysfunction group (P < 0.05). In order to minimize the effects of gait and cognitive dysfunction, we performed similar analysis among subjects with little or no such dysfunction, and obtained the same results (P < 0.05) as described above.


Urinary dysfunction was found to be closely related with right frontal hypoperfusion in iNPH using [123I]-IMP SPECT. This right frontal area is one of the critical areas for regulating micturition. While secondary incontinence can result from gait disturbance or dementia, there may also be a neurogenic mechanism underlying urinary dysfunction, which is a significant burden in patients with iNPH and their caregivers. Neurourol. Urodynam. 31:50–55, 2012. © 2011 Wiley Periodicals, Inc.