Principal component analysis of FDG PET in amnestic MCI

  • Flavio NobiliEmail author
  • Dario Salmaso
  • Silvia Morbelli
  • Nicola Girtler
  • Arnoldo Piccardo
  • Andrea Brugnolo
  • Barbara Dessi
  • Stig A. Larsson
  • Guido Rodriguez
  • Marco Pagani
Original Article



The purpose of the study is to evaluate the combined accuracy of episodic memory performance and 18F-FDG PET in identifying patients with amnestic mild cognitive impairment (aMCI) converting to Alzheimer’s disease (AD), aMCI non-converters, and controls.


Thirty-three patients with aMCI and 15 controls (CTR) were followed up for a mean of 21 months. Eleven patients developed AD (MCI/AD) and 22 remained with aMCI (MCI/MCI). 18F-FDG PET volumetric regions of interest underwent principal component analysis (PCA) that identified 12 principal components (PC), expressed by coarse component scores (CCS). Discriminant analysis was performed using the significant PCs and episodic memory scores.


PCA highlighted relative hypometabolism in PC5, including bilateral posterior cingulate and left temporal pole, and in PC7, including the bilateral orbitofrontal cortex, both in MCI/MCI and MCI/AD vs CTR. PC5 itself plus PC12, including the left lateral frontal cortex (LFC: BAs 44, 45, 46, 47), were significantly different between MCI/AD and MCI/MCI. By a three-group discriminant analysis, CTR were more accurately identified by PET-CCS + delayed recall score (100%), MCI/MCI by PET-CCS + either immediate or delayed recall scores (91%), while MCI/AD was identified by PET-CCS alone (82%). PET increased by 25% the correct allocations achieved by memory scores, while memory scores increased by 15% the correct allocations achieved by PET.


Combining memory performance and 18F-FDG PET yielded a higher accuracy than each single tool in identifying CTR and MCI/MCI. The PC containing bilateral posterior cingulate and left temporal pole was the hallmark of MCI/MCI patients, while the PC including the left LFC was the hallmark of conversion to AD.


18F-FDG PET Episodic memory Mild cognitive impairment Alzheimer’s disease 



This study complies with the current Italian laws and received ethical approval.

We thank Dr. Giampiero Villavecchia for supervising PET acquisition and Dr. Alessandra Piccini for performing ApoE evaluation.


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Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Flavio Nobili
    • 1
    • 2
    • 3
    Email author
  • Dario Salmaso
    • 4
    • 5
  • Silvia Morbelli
    • 6
  • Nicola Girtler
    • 1
    • 2
    • 3
  • Arnoldo Piccardo
    • 7
  • Andrea Brugnolo
    • 1
    • 2
    • 3
  • Barbara Dessi
    • 1
    • 2
    • 3
  • Stig A. Larsson
    • 8
  • Guido Rodriguez
    • 1
    • 2
    • 3
  • Marco Pagani
    • 4
    • 5
    • 8
  1. 1.Clinical Neurophysiology, Department of Endocrinological and Medical SciencesUniversity of GenoaGenoaItaly
  2. 2.Alzheimer Evaluation UnitS. Martino HospitalGenoaItaly
  3. 3.Head–Neck DepartmentS. Martino HospitalGenoaItaly
  4. 4.Institute of Cognitive Sciences and TechnologiesCNRRomeItaly
  5. 5.Institute of Cognitive Sciences and TechnologiesCNRPaduaItaly
  6. 6.Nuclear Medicine Unit, Department of Internal MedicineUniversity of GenoaGenoaItaly
  7. 7.Nuclear Medicine Unit, Department of Imaging DiagnosticsGalliera HospitalGenoaItaly
  8. 8.Department of Nuclear MedicineKarolinska HospitalStockholmSweden

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