Brain metabolic patterns in patients with suspected non-Alzheimer’s pathophysiology (SNAP) and Alzheimer’s disease (AD): is [18F] FDG a specific biomarker in these patients?

  • Agostino ChiaravallotiEmail author
  • Gaetano Barbagallo
  • Alessandro Martorana
  • Anna Elisa Castellano
  • Francesco Ursini
  • Orazio Schillaci
Original Article
Part of the following topical collections:
  1. Neurology



The present study was conducted to compare the pattern of brain [18F] FDG uptake in suspected non-Alzheimer’s pathophysiology (SNAP), AD, and healthy controls using 2-deoxy-2-[18F]fluoroglucose ([18F] FDG) positron emission tomography imaging. Cerebrospinal fluid (CSF) biomarkers amyloid-β1-42 peptide (Aβ1-42) and tau were used in order to differentiate AD from SNAP.


The study included 43 newly diagnosed AD patients (female = 23; male = 20) according to the NINCDS-ADRDA criteria, 15 SNAP patients (female = 12; male =3), and a group of 34 healthy subjects that served as the control group (CG), who were found to be normal at neurological evaluation (male = 20; female = 14). A battery of neuropsychological tests was administrated in AD and SNAP subjects; cerebrospinal fluid assay was conducted in both AD and SNAP as well. Brain PET/CT acquisition was started 30 ± 5 min after [18F] FDG injection in all subjects. SPM12 [statistical parametric mapping] implemented in MATLAB 2018a was used for the analysis of PET scans in this study.


As compared to SNAP, AD subjects showed significant hypometabolism in a wide cortical area involving the right frontal, parietal, and temporal lobes. As compared to CG, AD subjects showed a significant reduction in [18F] FDG uptake in the parietal, limbic, and frontal cortex, while a more limited reduction in [18F] FDG uptake in the same areas was found when comparing SNAP to CG.


SNAP subjects show milder impairment of brain [18F] FDG uptake as compared to AD. The partial overlap of the metabolic pattern between SNAP and AD limits the use of [18F] FDG PET/CT in effectively discriminating these clinical entities.


[18F] FDG Alzheimer, SNAP PET/CT Biomarkers 


[18F] FDG



Positron emission tomography


Computed tomography


Cerebrospinal fluid


Total tau


Phosphorylated tau



The authors wish to thank Tiziana Martino (IRCCS Neuromed) for data collection. This work was funded in part by the European Commission Horizon 2020 programme, grant 689209: PICASO, A Personalised Integrated Care Approach for Service Organisations and Care Models for Patients with Multi-Morbidity and Chronic Conditions.

Compliance with ethical standards

Conflict of interest

The authors report no financial disclosures/funding or conflict of interest.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and national research committee and with the1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Biomedicine and PreventionUniversity Tor VergataRomeItaly
  2. 2.IRCCS NeuromedPozzilliItaly
  3. 3.Institute of NeurologyUniversity Magna Graecia of CatanzaroCatanzaroItaly
  4. 4.UOSD Centro Demenze, Department of Systems MedicineUniversity of Roma Tor VergataRomeItaly
  5. 5.Department of Medical SciencesUniversity of FerraraFerraraItaly

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