FDG-PET and CSF phospho-tau for prediction of cognitive decline in mild cognitive impairment

Specific patterns of cortical glucose metabolism disturbances and increased CSF phospho-tau (p-tau181) concentrations could be demonstrated to predict cognitive decline and shift to dementia in amnestic mild cognitive impairment (MCI). But comparisons of both diagnostic tools have not been undertaken so far. The aim of the study was to compare 18F-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) findings and CSF phospho-tau (p-tau181) measurements in the prediction of cognitive deterioration and conversion to dementia in MCI. During follow-up (mean 19 months) eight of 16 patients (50%) showed progressive cognitive decline, and four patients shifted to dementia. Pathological FDG-PET and elevated p-tau181 levels both predicted deterioration. While p-tau181 was highly sensitive for cognitive decline, FDG-PET was superior in predicting conversion to clinical dementia in MCI patients.