Imaging and fluid biomarkers in frontotemporal dementia

Most of the validated biomarkers in frontotemporal dementia (FTD) are used to differentiate patients with FTD from patients with Alzheimer disease or from control individualsCurrently validated biomarkers in FTD include grey matter atrophy, alterations in brain metabolism as detected by 18F-fluorodeoxyglucose-PET and cerebrospinal fluid levels of amyloid-β1–42, phospho-tau181 and total-tau.New imaging biomarkers, detected via techniques such as arterial spin labelling and diffusion tensor imaging, are sensitive to the subtle changes that precede grey matter atrophy in FTD, potentially enabling use in diagnosis and disease monitoringPromising fluid biomarkers include neurofilament light chain (for staging, monitoring and prognosis in all FTD subtypes) and dipeptide-repeat proteins and progranulin (for target engagement in gene-specific forms of FTD)Reliable biomarkers that differentiate between tau pathology and TDP-43 pathology are still needed, to facilitate trials of disease-modifying treatmentsFuture research should focus on the multimodal combination of fluid and imaging biomarkers, as well as the harmonization of biomarker collection and analysis protocols