Amyloid deposits and response to shunt surgery in idiopathic normal-pressure hydrocephalus

Kotaro Hiraoka, Wataru Narita, Hirokazu Kikuchi, Toru Baba, Shigenori Kanno, Osamu Iizuka, Manabu Tashiro, Shozo Furumoto, Nobuyuki Okamura, Katsutoshi Furukawa, Hiroyuki Arai, Ren Iwata, Etsuro Mori, Kazuhiko Yanai

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


Abstract Objectives In previous studies, patients with idiopathic normal-pressure hydrocephalus (iNPH) occasionally showed Alzheimer's pathology in frontal lobe cortical biopsy during cerebrospinal fluid shunt surgery or intracranial pressure monitoring. In clinical practice, the differential diagnosis of iNPH from Alzheimer's disease (AD) can be problematic, particularly because some iNPH cases exhibit AD comorbidity. In this study, we evaluated amyloid deposition in the brains of patients with iNPH before shunt surgery, and investigated the association between brain amyloid deposits and clinical improvement following the surgery. Materials & methods Amyloid imaging was performed in patients with iNPH or AD and also in healthy control subjects by using positron emission tomography (PET) and a radiolabeled pharmaceutical compound, 11C-BF227. Using the cerebellar hemispheres as reference regions, the standard uptake value ratio (SUVR) of the neocortex was estimated and used as an index for amyloid deposition. In patients with iNPH, clinical symptoms were assessed before shunt surgery and 3 months after surgery. Results Five of the 10 patients with iNPH had neocortical SUVRs that were as high as those of AD subjects, whereas the SUVRs of the 5 patients were as low as those of healthy controls. A significant inverse correlation between neocortical SUVRs and cognitive improvements after shunt surgery was observed in iNPH. Conclusions The amount of amyloid deposits ranges widely in the brains of patients with iNPH and is associated with the degree of cognitive improvement after shunt surgery.

Original languageEnglish
Article number13858
Pages (from-to)124-128
Number of pages5
JournalJournal of the neurological sciences
Issue number1-2
Publication statusPublished - 2015 Sept 15


  • Alzheimer's disease
  • Amyloid
  • Dementia
  • Idiopathic normal-pressure hydrocephalus
  • Positron emission tomography (PET)
  • Shunt surgery

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology


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