18F-FDG PET for Prediction of Conversion to Alzheimer's Disease Dementia in People with Mild Cognitive Impairment: An Updated Systematic Review of Test Accuracy.
Journal of Alzheimer's disease : JAD
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Grbic-Smailagic, N., Lafortune, L., Kelly, S., Hyde, C., & Brayne, C. (2018). 18F-FDG PET for Prediction of Conversion to Alzheimer's Disease Dementia in People with Mild Cognitive Impairment: An Updated Systematic Review of Test Accuracy.. Journal of Alzheimer's disease : JAD, 64 (4), 1175-1194. https://doi.org/10.3233/jad-171125
Background A previous Cochrane systematic review concluded there is insufficient evidence to support the routine use of ¹⁸F-FDG PET in clinical practice in people with Mild Cognitive Impairment (MCI). Objectives To –update the evidence and reassess ¹⁸F-FDG-PET’s accuracy for detecting people with MCI at baseline who would clinically convert to AD dementia at follow-up. Methods A systematic review including comprehensive search of electronic databases from January 2013 to July 2017, to update original searches (1999 to 2013). All key review steps, including quality assessment using QUADAS 2, were performed independently and blindly by two review authors. Meta-analysis could not be conducted due to heterogeneity across studies. Results When all included studies were examined across all semi-quantitative and quantitative metrics, exploratory analysis for conversion of MCI to AD dementia (n=24) showed highly variable accuracy – half the studies failed to meet four or more of the seven sets of QUADAS 2 criteria. Variable accuracy for all metrics was also found across eleven newly included studies, published in the last 5 years (range: sensitivity 56-100%, specificity 24-100%). The most consistently high sensitivity and specificity values (approximately ≥80%) were reported for the sc-SPM (single case statistical parametric mapping) metric in 6 out of 8 studies. Conclusion Systematic and comprehensive assessment of studies of 18FDG-PET for prediction of conversion from MCI to AD dementia reveals many studies have methodological limitations according to the Cochrane diagnostic test accuracy gold standards, and shows accuracy remains highly variable, including in the most recent studies. There is some evidence, however, of higher and more consistent accuracy in studies using computer aided metrics, such as sc-SPM, in specialised clinical settings. Robust, methodologically sound prospective longitudinal cohort studies with long (≥5 years) follow-up, larger consecutive samples, and defined baseline threshold(s) are needed to test these promising results. Further evidence of the clinical validity and utility of 18F-FDG PET in people with MCI is needed. Key words Mild cognitive impairment, 18F-FDG PET, test accuracy, predictive value, conversion, Alzheimer’s Disease dementia
Brain, Humans, Alzheimer Disease, Disease Progression, Fluorodeoxyglucose F18, Positron-Emission Tomography, Neuropsychological Tests, Cognitive Dysfunction
National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care East of England (Grant number: RG74482).
External DOI: https://doi.org/10.3233/jad-171125
This record's URL: https://www.repository.cam.ac.uk/handle/1810/280542