Automated discrimination between very early Alzheimer disease and controls using an easy Z-score imaging system for multicenter brain perfusion single-photon emission tomography.
OBJECTIVE
In Alzheimer disease (AD), a peculiar regional cerebral blood flow (rCBF) abnormality has been reported in the posterior cingulate gyri and precunei, even at a very early stage. We performed a multicenter brain perfusion single-photon emission tomography (SPECT) study to evaluate the discrimination ability of an easy Z-score imaging system (eZIS) with a common normal data base between patients with very early AD at the stage of mild cognitive impairment and age-matched healthy controls.


METHODS
For a multicenter study, SPECT images of 40 patients with AD and 40 healthy volunteers were acquired from 4 gamma camera systems in 4 different institutions. Systematic differences of SPECT images between gamma cameras were corrected by using conversion maps calculated from the SPECT images of the same brain phantom. Receiver operating characteristic (ROC) analysis was performed to discriminate patients and controls by using a Z-score in the volume of interest (VOI), which had been defined as a region related to AD in subjects other than those in a multicenter study.


RESULTS
Bilateral posterior cingulate gyri, precunei, and parietal cortices were defined as a VOI showing rCBF reduction in very early AD. A new indicator of rCBF abnormality in the VOI provided 86% accuracy for distinction of AD and healthy controls in the multicenter study. The area under the ROC curve was 0.934.


CONCLUSIONS
Because an eZIS can use a common normal data base by converting site-specific SPECT data to the core data, the eZIS was useful for automated diagnosis of very early AD in routine studies in multiple institutions.
Matsuda
H
H
Department of Nuclear Medicine, Saitama Medical University Hospital, Japan. matsudah@saitama-med.ac.jp
Mizumura
S
S
Nagao
T
T
Ota
T
T
Iizuka
T
T
Nemoto
K
K
Takemura
N
N
Arai
H
H
Homma
A
A
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000523:psychology; D001921:Brain / Q000000981:diagnostic imaging; D002560:Cerebrovascular Circulation; D003071:Cognition; D005260:Female; D006179:Gyrus Cinguli / Q000098:blood supply; D006801:Humans; D008297:Male; D008568:Memory; D008875:Middle Aged; D010296:Parietal Lobe / Q000098:blood supply; D015899:Tomography, Emission-Computed, Single-Photon