ObjectiveThe aim of this study was to explore the prognostic values of biomarkers of neurodegeneration as measured by magnetic resonance imaging (MRI) and amyloid burden as measured by amyloid positron emission tomography (PET) in predicting conversion to Alzheimer's disease (AD) in patients with mild cognitive impairment (MCI).MethodsPubMed and EMBASE databases were searched for structural MRI or amyloid PET imaging studies published between January 2000 and July 2014 that reported conversion to AD in patients with MCI. Means and standard deviations or individual numbers of biomarkers with positive or negative status at baseline and corresponding numbers of patients who had progressed to AD at follow-up were retrieved from each study. The effect size of each biomarker was expressed as Hedges's g.ResultsTwenty-four MRI studies and 8 amyloid PET imaging studies were retrieved. 674 of the 1741 participants (39%) developed AD. The effect size for predicting conversion to AD was 0.770 [95% confidence interval (CI) 0.607–0.934] for across MRI and 1.316 (95% CI 0.920–1.412) for amyloid PET imaging (p<0.001). The effect size was 1.256 (95% CI 0.902–1.609) for entorhinal cortex volume from MRI.ConclusionOur study suggests that volumetric MRI measurement may be useful for the early detection of AD.

Alzheimer's disease (AD) has an insidious onset with a slowly progressive course. Mild cognitive impairment (MCI) is an intermediate stage between cognitively normal and AD. In particular, amnestic MCI is considered as a prodromal stage of AD. MCI may therefore be a target for the prediction of who will develop AD prediction. Several markers during the prodromal MCI stage, including neuropsychological tests, have been proposed for the prediction of AD. However, no Print ISSN 1738-3684 / On-line ISSN 1976 OPEN ACCESS Copyright © 2017 Korean Neuropsychiatric Association 205single study has included enough data to provide a reliable predictor of AD. The International Working Group (IWG) and National Institute on Aging Alzheimer's Association (NIA-AA) has proposed several biomarkers as diagnostic criteria for MCI, including cerebro spinal fluid (CSF) amyloid beta (Aβ) and tau, atrophy on MRI, glucose metabolism on [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) and fibrillar Aβ burden on amyloid PET. 1,2 FDG-PET has been suggested to be the strongest predictor for progression from MCI to AD, 3 however, its high costs may limit its widespread adoption. A CSF assessment requires a lumbar puncture, which is regarded an invasive procedure, although it is widely implemented without problems in the elderly. In contrast, MRI is noninvasive, widely used in clinical settings and also could be easily performed. Atrophy measurements on MRI have been used to predict the progression to AD inpatients with MCI since the 1990s. Most studies have

Alzheimer's disease (AD) has an insidious onset with a slowly progressive course. Mild cognitive impairment (MCI) is an intermediate stage between cognitively normal and AD. In particular, amnestic MCI is considered as a prodromal stage of AD. MCI may therefore be a target for the prediction of who will develop AD prediction. Several markers during the prodromal MCI stage, including neuropsychological tests, have been proposed for the prediction of AD. However, no Print ISSN 1738-3684 / On-line ISSN 1976 OPEN ACCESS Copyright © 2017 Korean Neuropsychiatric Association 205single study has included enough data to provide a reliable predictor of AD. The International Working Group (IWG) and National Institute on Aging Alzheimer's Association (NIA-AA) has proposed several biomarkers as diagnostic criteria for MCI, including cerebro spinal fluid (CSF) amyloid beta (Aβ) and tau, atrophy on MRI, glucose metabolism on [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) and fibrillar Aβ burden on amyloid PET. 1,2 FDG-PET has been suggested to be the strongest predictor for progression from MCI to AD, 3 however, its high costs may limit its widespread adoption. A CSF assessment requires a lumbar puncture, which is regarded an invasive procedure, although it is widely implemented without problems in the elderly. In contrast, MRI is noninvasive, widely used in clinical settings and also could be easily performed. Atrophy measurements on MRI have been used to predict the progression to AD inpatients with MCI since the 1990s. Most studies have

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