Relevance of functional neuroimaging in the progression of mild cognitive impairment.
OBJECTIVE
To assess whether combining neuropsychological tests and cerebral blood flow markers improves progression accuracy from mild cognitive impairment (MCI) to Alzheimer's disease (AD) than each of them on its own.


METHODS
Forty-two patients were investigated prospectively, undergoing baseline and 3-year follow-up neuropsychological tests and neuroimaging with Tc-ECD-SPECT. Twenty-one patients had developed AD while 21 retained their initial diagnosis. The relative blood flow and cognitive differences were studied. Validity parameters, multivariant analysis and logistic regression model were calculated.


RESULTS
Patients who deteriorated showed lower scoring than stable subjects in some neuropsychological tests (p = 0.03-0.001) and in relative blood flow in selected regions (8-10%). Low cognitive test scoring and low relative blood flow in some regions showed sensibilities and specificities from 70% to 86% for the diagnosis of early Alzheimer's disease. The relative risk of progression to AD was up to 4.7 times higher for these patients (p = 0.0001). The left frontal relative blood flow, the CAMCOG and orientation scoring were the best data to predict the risk of progression to AD.


CONCLUSIONS
The combination of functional imaging and neuropsychological tests can diagnose with high sensitivity and specificity if a patient is suffering cognitive impairment in its early stages, and may aid in predicting the risk of developing dementia.
Cabranes
José A
JA
Department of Nuclear Medicine, Hospital Clínico San Carlos, Madrid, Spain. jcabranes.hcsc@salud.madrid.org
De Juan
Ramón
R
Encinas
Marta
M
Marcos
Alberto
A
Gil
Pedro
P
Fernández
Cristina
C
De Ugarte
Carmen
C
Barabash
Ana
A
D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D003072:Cognition Disorders / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000523:psychology; D003545:Cysteine / Q000031:analogs & derivatives*; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D009483:Neuropsychological Tests; D015609:Organotechnetium Compounds; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D015899:Tomography, Emission-Computed, Single-Photon
D015609:Organotechnetium Compounds; C059659:technetium Tc 99m bicisate; D003545:Cysteine