Neurodegenerative
dementias are characterized by the abnormal accumulation of misfolded
proteins. However, its diagnostic criteria are still based on the clinical phenotype. The development of
biomarkers allowed in vivo detection of pathophysiological processes. This article aims to make a non-systematic review of the use of molecular neuroimaging as a
biomarker. Molecular neuroimaging is based on the use of radiotracers for image acquisition. The radiotracer most used in PET is 18F-fluorodeoxyglucose (FDG), with which it is possible to study the regional brain
glucose metabolism. The pattern of regional hypometabolism provides neuroanatomical information on the neurodegenerative process, which, in turn, has a good specificity for each type of
proteinopathy. FDG is very useful in the differential diagnosis of neurodegenerative
dementias through the regional pattern of involvement, including
dementia with Lewy bodies and the spectrum of
frontotemporal dementia. More recently, radiotracers with specific
ligands to some of the pathological
proteins have been developed.
Pittsburgh compound B (PIB) labeled with 11C and the
ligands that use 18F (
florbetapir,
florbetaben and
flutemetamol) are the most used radiotracers for the detection of insoluble β-
amyloid peptide in
Alzheimer's disease (AD). A first generation of
ligands for
tau protein has been developed, but it has some affinity for other non-
tau protein aggregates. A second generation has the advantage of having a higher affinity for hyperphosphorylated
tau protein, including in primary
tauopathies.