title: Identification of diabetes-related dementia: Longitudinal perfusion SPECT and amyloid PET studies.
abstract: OBJECTIVE
  We attempted to identify a dementia subgroup with characteristics associated with diabetes mellitus (DM)-related metabolic abnormalities, referred to as diabetes-related dementia, using longitudinal single photon emission computed tomography (SPECT) and Pittsburgh compound-B (PiB) positron emission tomography (PET).
  
  
  METHODS
  We classified 175 patients with clinically diagnosed Alzheimer disease (AD) and DM into 4 subgroups based on brain imaging in a 2013 study. Among them, we investigated follow-up SPECT studies in 29 patients of an AD group showing decreased regional cerebral blood flow (rCBF) of the parietotemporal lobe on initial SPECT and 18 patients of a diabetes-related dementia group showing neither decreased rCBF of the parietotemporal lobe nor cerebrovascular disease, which is strongly associated with DM-related factors. Eleven of them underwent PiB PET.
  
  
  RESULTS
  Follow-up SPECT showed more profound rCBF reduction in the parietotemporal lobe and other areas of the AD group, whereas follow-up SPECT showed an rCBF reduction in small areas of the frontotemporal and limbic lobes of the diabetes-related dementia group. Six of 9 patients with diabetes-related dementia were negative or equivocal for PiB binding.
  
  
  CONCLUSIONS
  A subset of a dementia subgroup with characteristics predominantly associated with DM-related factors may underlie a pathophysiology different from AD, although these patients were clinically diagnosed as having AD. The identification of diabetes-related dementia may be necessary for considering an appropriate therapy and prevention in clinical practice.
authors.affiliation: Department of Geriatric Medicine, Tokyo Medical University, Tokyo, Japan.
authors.forename: Raita
authors.initials: R
authors.lastname: Fukasawa
authors.affiliation: Department of Geriatric Medicine, Tokyo Medical University, Tokyo, Japan. Electronic address: h-hanyu@tokyo-med.ac.jp.
authors.forename: Haruo
authors.initials: H
authors.lastname: Hanyu
authors.affiliation: Department of Geriatric Medicine, Tokyo Medical University, Tokyo, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Shimizu
authors.affiliation: Department of Geriatric Medicine, Tokyo Medical University, Tokyo, Japan.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Kanetaka
authors.affiliation: Department of Geriatric Medicine, Tokyo Medical University, Tokyo, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Sakurai
authors.affiliation: Department of Geriatric Medicine, Tokyo Medical University, Tokyo, Japan; Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ishii
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000503:physiopathology; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D003704:Dementia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D048909:Diabetes Complications; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D049268:Positron-Emission Tomography; D015899:Tomography, Emission-Computed, Single-Photon
keywords: Alzheimer disease; Dementia; Diabetes mellitus; Diabetes-related dementia; Pittsburgh compound-B PET; Single photon emission CT