DOI: 10.1007/s00259-018-4034-zPages: 1526-1533

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

1. VU University Medical Center, Department of Neurology & Alzheimer Center, Amsterdam Neuroscience

2. IRCCS S. Giovanni di Dio, Fatebenefratelli, Alzheimer Operative Unit

3. IRCCS S. Giovanni di Dio, Fatebenefratelli, LANE – Laboratory of Alzheimer’s Neuroimaging & Epidemiology

4. University of Brescia, Department of Molecular and Translational Medicine

5. Vita-Salute San Raffaele University, Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute

6. University of Navarra, Department of Nuclear Medicine, Clinica Universidad de Navarra

7. University Hospital of Cologne, University of Cologne and German Center for Neurodegenerative Diseases (DZNE), Department of Nuclear Medicine

8. German Center for Neurodegenerative Diseases (DZNE)

9. University of Queensland and at the Mater Hospital Brisbane, Queensland Brain Institute

10. University of Genoa, Clinical Neurology and Polyclinic IRCCS San Martino-IST, Department of Neuroscience (DINOGMI)

11. University College London, Division of Psychiatry & Essex Partnership University NHS Foundation Trust

12. University of Genoa, Nuclear Medicine Unit, San Martino Hospital, Department of Health Sciences

13. University of Geneva, LANVIE (Laboratoire de Neuroimagerie du Vieillissement), Department of Psychiatry

Correspondence to:
Flavio Nobili
Tel: 0039.010.3537568




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).


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.


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.


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.

This article is freely available, click here to access the full text/PDF

  • Accepted: Apr 16, 2018
  • Online: May 9, 2018

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