Cingulate cortex hypoperfusion predicts Alzheimer's disease in mild cognitive impairment.
BACKGROUND
Mild cognitive impairment (MCI) was recently described as a heterogeneous group with a variety of clinical outcomes and high risk to develop Alzheimer's disease (AD). Regional cerebral blood flow (rCBF) as measured by single photon emission computed tomography (SPECT) was used to study the heterogeneity of MCI and to look for predictors of future development of AD.


METHODS
rCBF was investigated in 54 MCI subjects using Tc-99m hexamethylpropyleneamine oxime (HMPAO). An automated analysis software (BRASS) was applied to analyze the relative blood flow (cerebellar ratios) of 24 cortical regions. After the baseline examination, the subjects were followed clinically for an average of two years. 17 subjects progressed to Alzheimer's disease (PMCI) and 37 subjects remained stable (SMCI). The baseline SPECT ratio values were compared between PMCI and SMCI. Receiver operating characteristic (ROC) analysis was applied for the discrimination of the two subgroups at baseline.


RESULTS
The conversion rate of MCI to AD was 13.7% per year. PMCI had a significantly decreased rCBF in the left posterior cingulate cortex, as compared to SMCI. Left posterior cingulate rCBF ratios were entered into a logistic regression model for ROC curve calculation. The area under the ROC curve was 74%-76%, which indicates an acceptable discrimination between PMCI and SMCI at baseline.


CONCLUSIONS
A reduced relative blood flow of the posterior cingulate gyrus could be found at least two years before the patients met the clinical diagnostic criteria of AD.
Huang
Chaorui
C
Karolinska Institutet, Department of Clinical Neuroscience, Occupational Therapy and Elderly Care Research (NEUROTEC), Divison of Geriatric Medicine, Huddinge University Hospital, Sweden. chaorui.huang@neurotec.ki.se
Wahlund
Lars-Olof
LO
Svensson
Leif
L
Winblad
Bengt
B
Julin
Per
P
D000544:Alzheimer Disease / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation; D003072:Cognition Disorders / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006179:Gyrus Cinguli / Q000098:blood supply* / Q000000981:diagnostic imaging*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon
D019690:Technetium Tc 99m Exametazime