Clinical information and FDG PET scan data will be electronically transferred in a secure and confidential manner to the GLIMPS database at TARGET of the RUG, where the image-based classification algorithm will be performed. Individual physicians of the departments of Neurology, Geriatrics, or Nuclear Medicine of each participating center will each receive a username and password which they can use to access the GLIMPS database. Each participating center has its own center number under which all patients of that center can be uploaded. Before patient information can be stored in the database, patients have to be informed about the purpose of the project and they have to sign informed consent for the anonymous storage of their patient data. Inclusion criteria for the GLIMPS project are patients who are suspected of having a neurodegenerative brain disease and in whom the physician has a clinical reason to perform an FDG PET scan. After informed consent, clinical and scan information can be uploaded to the GLIMPS database. In this database, each patient will receive a GLIMPS number. This number will need to be stored together with the medical chart of the patient, in order to inform the referring physician which patient belongs to which number. In this way the referring physician can access the own patient population so that necessary additions or repeated studies can be added. The data of patients of the other centers are not accessible. After complete upload of all necessary data, the image-based classification algorithm will be applied by the researchers of the GLIMPS project and feedback will be given within two weeks. This feedback will consist of z-scores of each of the known disease-related metabolic brain patterns (currently PD, MSA, PSP and AD).