Radiotracers for Amyloid Imaging in Neurodegenerative Disease: State-of-the-Art and Novel Concepts

The pathological accumulation of different peptides is the common base of many neurodegenerative processes, such as Alzheimer's disease (AD). AD is characterized by amyloid deposits which may cause alterations in neurotransmission, activation of inflammatory mechanisms, neuronal death and cerebral atrophy. Diagnosis in vivo is challenging as the criteria rely mainly on clinical manifestations, which become evident only in a late stage of the disease. While AD can currently be definitively confirmed by postmortem histopathologic examination, in vivo imaging may improve the clinician's ability to identify AD at the earliest stage. In this regard, the detection of cerebral amyloid plaques with positron emission tomography (PET) is likely to improve diagnosis and allow for a prompt start of an effective therapy. Many PET imaging probes for AD-specific pathological modifications have been developed and proved effective in detecting amyloid deposits in vivo. We here review the current knowledge on PET imaging in the detection of amyloid deposits and their application in the diagnosis of AD.