"Occipital Tunnel" Sign on FDG PET for Differentiating Dementias

David M. Sawyer, Phillip H. Kuo

Research output: Contribution to journalArticle

3 Scopus citations


PET using FDG is a critical tool for evaluation of dementias, with characteristic patterns of hypometabolism suggesting specific diagnoses. Hypometabolism in the occipital region is recognized as an important finding associated with dementia with Lewy bodies and posterior cortical atrophy. We describe here the novel "occipital tunnel" sign, which results from relative sparing of FDG uptake in the medial occipital (primary visual) cortex compared with more severe loss in the surrounding lateral occipital (visual association) cortex. This sign is useful for recognizing the occipital findings of dementia with Lewy bodies and posterior cortical atrophy, especially when viewing sagittal projections.

Original languageEnglish (US)
Pages (from-to)e59-e61
JournalClinical Nuclear Medicine
Issue number2
Publication statusPublished - Feb 1 2018



  • Alzheimer disease
  • dementia
  • dementia with Lewy bodies
  • neurodegenerative disease
  • posterior cortical atrophy

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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