Diagnostic utility of FDG-PET in the differential diagnosis between different forms of primary progressive aphasia

• Published in: European journal of nuclear medicine and molecular imaging 2018-07, Vol.45 (9), p.1526-1533
• Main Authors: Bouwman, Femke, Orini, Stefania, Gandolfo, Federica, Altomare, Daniele, Festari, Cristina, Agosta, Federica, Arbizu, Javier, Drzezga, Alexander, Nestor, Peter, Nobili, Flavio, Walker, Zuzana, Morbelli, Silvia, Boccardi, Marina
• Format: Article
• Language: English
• Subjects: Aphasia; Aphasia, Primary Progressive - diagnostic imaging; Atrophy; Brain - diagnostic imaging; Cardiology; Dementia; Diagnosis, Differential; Diagnostic systems; Differential diagnosis; Experimental allergic neuritis; Fluorodeoxyglucose F18; Guidelines; Humans; Imaging; Medical diagnosis; Medicine; Medicine & Public Health; Neurodegeneration; Neurodegenerative diseases; Neurological diseases; Neurology; Nuclear Medicine; Oncology; Orthopedics; Positron emission; Positron emission tomography; Quality assessment; Quality control; Radiology; Tomography
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-018-4034-z

Purpose A joint effort of the European Association of Nuclear Medicine (EANM) and the European Academy of Neurology (EAN) aims at clinical guidance for the use of FDG-PET in neurodegenerative diseases. This paper addresses the diagnostic utility of FDG-PET over clinical/neuropsychological assessment in the differentiation of the three forms of primary progressive aphasia (PPA). Methods Seven panelists were appointed by the EANM and EAN and a literature search was performed by using harmonized PICO (Population, Intervention, Comparison, Outcome) question keywords. The studies were screened for eligibility, and data extracted to assess their methodological quality. Critical outcomes were accuracy indices in differentiating different PPA clinical forms. Subsequently Delphi rounds were held with the extracted data and quality assessment to reach a consensus based on both literature and expert opinion. Results Critical outcomes for this PICO were available in four of the examined papers. The level of formal evidence supporting clinical utility of FDG-PET in differentiating among PPA variants was considered as poor. However, the consensual recommendation was defined on Delphi round I, with six out of seven panelists supporting clinical use. Conclusions Quantitative evidence demonstrating utility or lack thereof is still missing. Panelists decided consistently to provide interim support for clinical use based on the fact that a typical atrophy or metabolic pattern is needed for PPA according to the diagnostic criteria, and the synaptic failure detected by FDG-PET is an earlier phenomenon than atrophy. Also, a normal FDG-PET points to a non-neurodegenerative cause.