MAPT and frontotemporal dementia: Additional tests sometimes used in the assessment of patients with FTD include fluorodeoxyglucose (FDG)-PET or amyloid-PET to rule out Alzheimer disease (AD), and lumbar puncture to rule out FTD mimics such as inflammatory or infectious diseases, or to rule out AD using CSF biomarkers for amyloid beta and phospho-tau [38].