RESUMO
BACKGROUND: Diagnosing Alzheimer's disease (AD) in its earliest stages is important for therapeutic and support planning. Similarly, being able to predict who will convert from mild cognitive impairment (MCI) to AD would have clinical implications. OBJECTIVES: The goals of this study were to identify features from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database associated with the conversion from MCI to AD, and to characterize the temporal evolution of that conversion. METHODS: We screened the publically available ADNI longitudinal database for subjects with MCI who have developed AD (cases: n=305), and subjects with MCI who have remained stable (controls: n=250). Analyses included 1,827 features from laboratory assays (n=12), quantitative MRI scans (n=1,423), PET studies (n=136), medical histories (n=72), and neuropsychological tests (n=184). Statistical longitudinal models identified features with significant differences in longitudinal behavior between cases and matched controls. A multiple-comparison adjusted log-rank test identified the capacity of the significant predictive features to predict early conversion. RESULTS: 411 features (22.5%) were found to be statistically different between cases and controls at the time of AD diagnosis; 385 features were statistically different at least 6 months prior to diagnosis, and 28 features distinguished early from late conversion, 20 of which were obtained from neuropsychological tests. In addition, 69 features (3.7%) had statistically significant changes prior to AD diagnosis. CONCLUSION: Our results characterized features associated with disease progression from MCI to AD, and, in addition, the log-rank test identified features which are associated with the risk of early conversion.
Assuntos
Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/psicologia , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/psicologia , Progressão da Doença , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Seguimentos , Humanos , Estudos Longitudinais , Imageamento por Ressonância Magnética/tendências , Masculino , Testes Neuropsicológicos , Fatores de TempoRESUMO
An 11-year-old boy presented with a femur fracture, bone hypomineralization, and hypophosphatemia, suggesting tumor-induced rickets. Conventional radiologic techniques including magnetic resonance skeletal survey did not identify a tumor. Magnetic resonance gradient echo recall imaging demonstrated a 3-cm iliac tumor, the resection of which rapidly reversed metabolic abnormalities. This technique may be useful in identifying elusive tumors associated with tumor-induced rickets.