A review of the recent advances in neuroimaging of frontotemporal lobar degeneration

INTRODUCTION: The term "frontotemporal lobar degeneration" (FTLD) includes a large set of neurodegenerative diseases, which are heterogeneous in their genetic, pathologic and clinical aspects. This review will focus on the most recent contribution of neuroimaging tools on the diagnosis, characterization and pathogenesis of FTLD. EVIDENCE ACQUISITION: Scopus, Ovid, PubMed and MEDLINE were searched for articles published from January 2012 up to December 2014. Searches were limited to articles published in English. Frontotemporal lobar degeneration as a key word was always in the search queries in combination with logic AND, and at least one other key word. EVIDENCE SYNTHESIS: We found 91 papers of interest and reviewed their contents, finding in particular 4 major topics: the contribution of neuroimaging on the differential diagnosis; patients' functional characterization; new neuroimaging tools under development and pre-symptomatic genetic forms. CONCLUSIONS: Neuroimaging techniques have shown to be useful supporting tools in diagnosis, even if not always determinant to reach a conclusive decision, and quite important to identify phenocopies. At the moment, there is not a neuroimaging biomarker that could track the progressive course of dementias and the effect of therapies, but it is possible that in the future Diffusion Tensor Imaging and molecular imaging could fill this void. Monitoring the evolution of the pathology in vivo for at least 5 years is essential, and this would only be possible in a large multicenter study; asymptomatic forms would require even longer observation periods.