PET-FDG test-retest reliability during a visual discrimination task in schizophrenia.
OBJECTIVE
Reliability of assessment is important in any kind of neuropsychiatric study, but is particularly pivotal in schizophrenia research where symptom instability is common.


METHODS
Two fluorodeoxyglucose PET scans, 1 week apart, were carried out in schizophrenic patients while they were performing a simple visual discrimination task. Subject and scan conditions were held constant. Regional metabolic rates of glucose utilization were calculated as absolute and scaled; they were compared using correlational statistics.


RESULTS
Average differences between scans were 5-9% for the parietal and occipital cortices, but 1-3% for other cortical areas, differences comparable with reported variances in normal controls.


CONCLUSIONS
These results suggest that test-retest variance in metabolic imaging in schizophrenia is relatively low and that task performance increases metabolic stability in brain areas unrelated to task performance.
Maryland Psychiatric Research Center, Baltimore.
H H
HH
Holcomb
N G
NG
Cascella
D R
DR
Medoff
E A
EA
Gastineau
H
H
Loats
G K
GK
Thaker
R R
RR
Conley
R F
RF
Dannals
H N
HN
Wagner
C A
CA
Tamminga
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging*; D003847:Deoxyglucose / Q000031:analogs & derivatives*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000503:physiopathology; D014055:Tomography, Emission-Computed; D014796:Visual Perception
D019788:Fluorodeoxyglucose F18; D003847:Deoxyglucose