Integrity of Neurocognitive Networks in Dementing Disorders as Measured with Simultaneous PET/Functional MRI

Isabelle Ripp, Thomas Stadhouders, Alexandre Savio, Oliver Goldhardt, Jorge Cabello, Vince Calhoun, Valentin Riedl, Dennis Hedderich, Janine Diehl-Schmid, Timo Grimmer, Igor Yakushev

Research output: Contribution to journalArticlepeer-review

Abstract

Functional MRI (fMRI) studies have reported altered integrity of large-scale neurocognitive networks (NCNs) in dementing disorders. However, findings on the specificity of these alterations in patients with Alzheimer disease (AD) and behavioral-variant frontotemporal dementia (bvFTD) are still limited. Recently, NCNs have been successfully captured using PET with 18F-FDG. Methods: Network integrity was measured in 72 individuals (38 male) with mild AD or bvFTD, and in healthy controls, using a simultaneous resting-state fMRI and 18F-FDG PET. Indices of network integrity were calculated for each subject, network, and imaging modality. Results: In either modality, independent-component analysis revealed 4 major NCNs: anterior default-mode network (DMN), posterior DMN, salience network, and right central executive network (CEN). In fMRI data, the integrity of the posterior DMN was found to be significantly reduced in both patient groups relative to controls. In the AD group the anterior DMN and CEN appeared to be additionally affected. In PET data, only the integrity of the posterior DMN in patients with AD was reduced, whereas 3 remaining networks appeared to be affected only in patients with bvFTD. In a logistic regression analysis, the integrity of the anterior DMN as measured with PET alone accurately differentiated between the patient groups. A correlation between indices of 2 imaging modalities was low overall. Conclusion: FMRI and 18F-FDG PET capture partly different aspects of network integrity. A higher disease specificity for NCNs as derived from PET data supports metabolic connectivity imaging as a promising diagnostic tool.

Original languageEnglish (US)
Pages (from-to)1341-1347
Number of pages7
JournalJournal of nuclear medicine : official publication, Society of Nuclear Medicine
Volume61
Issue number9
DOIs
StatePublished - Sep 1 2020
Externally publishedYes

Keywords

  • Alzheimer disease
  • frontotemporal dementia
  • multimodal neuroimaging
  • PET
  • resting-state networks

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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