Reproducibility of regional brain metabolic responses to lorazepam

Gene Jack Wang, Nora D. Volkow, John Overall, Robert J. Hitzemann, Naomi Pappas, Kathy Pascani, Joanna S. Fowler

Research output: Contribution to journalArticlepeer-review

40 Scopus citations

Abstract

Changes in regional brain glucose metabolism in response to benzodiazepine agonists have been used as indicators of benzodiazepine-GABA receptor function. The purpose of this study was to assess the reproducibility of these responses. Methods: Sixteen healthy right-handed men underwent scanning with PET and [18F]fluorodeoxyglucose (FDG) twice: before placebo and before lorazepam (30 μg/kg). The same double FDG procedure was repeated 6-8 wk later on the men to assess test-retest reproducibility. Results: The regional absolute brain metabolic values obtained during the second evaluation were significantly lower than those obtained from the first evaluation regardless of condition (p ≤ 0.001). Lorazepam significantly and consistently decreased both whole-brain metabolism and the magnitude. The regional pattern of the changes were comparable for both studies (12.3% ± 6.9% and 13.7% ± 7.4%). Lorazepam effects were the largest in the thalamus (22.2% ± 8.6% and 22.4% ± 6.9%) and occipital cortex (19% ± 8.9% and 21.8% ± 8.9%). Relative metabolic measures were highly reproducible both for pharmacologic and replication condition. Conclusion: This study measured the test-retest reproducibility in regional brain metabolic responses, and although the global and regional metabolic values were significantly lower for the repeated evaluation, the response to lorazepam was highly reproducible.

Original languageEnglish (US)
Pages (from-to)1609-1613
Number of pages5
JournalJournal of Nuclear Medicine
Volume37
Issue number10
StatePublished - Oct 1996

Keywords

  • cerebral glucose metabolism
  • lorazepam
  • pharmacological challenge

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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