Methacholine-induced temporal changes in airway geometry and lung density by CT

Israel Amirav, Sandra S. Kramer, Michael M. Grunstein

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Purpose: Electron-beam CT (EBCT) was utilized to assess the time course of changes in airways cross-sectional area (CSA) and lung density during methacholine-induced bronchoconstriction. Materials and methods: EBCT scans (200 ms, 3-mm thickness, 2 mm increments) were obtained before (baseline) and 30 s, 2 min, and 4 min after bolus IV injection of methacholine to pigs receiving mechanical ventilation. A total of seven experiments were analyzed using custom-made image analysis software. With each challenge, five different airways and 50 lung regions of interest were studied. Results: The time course of lung density changes paralleled the time course for CSA changes. The maximal response to methacholine, measured in terms of both CSA and lung density changes, occurred 30 s after injection. Lung density changes were unaffected by reconstruction algorithm, normal (standard) or sharp (high resolution). Overall, there was increased air content in the lung during bronchoconstriction. This effect was significantly greater at the dependent lung regions. Conclusions: EBCT is an effective tool to assess temporal and regional changes in the lung during bronchoconstriction. Measurements of lung density during bronchoconstriction allow for assessment of peripheral changes that are beyond the CT spatial resolution of airways anatomy.

Original languageEnglish
Pages (from-to)1878-1885
Number of pages8
JournalChest
Volume119
Issue number6
DOIs
StatePublished - 2001
Externally publishedYes

Keywords

  • Bronchoconstriction
  • CT
  • Electron beam CT
  • Image processing
  • Lung density
  • Methacholine

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