TY - JOUR
T1 - Methacholine-induced temporal changes in airway geometry and lung density by CT
AU - Amirav, Israel
AU - Kramer, Sandra S.
AU - Grunstein, Michael M.
PY - 2001/6
Y1 - 2001/6
N2 - 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.
AB - 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.
KW - Bronchoconstriction
KW - CT
KW - Electron beam CT
KW - Image processing
KW - Lung density
KW - Methacholine
UR - http://www.scopus.com/inward/record.url?scp=0034892334&partnerID=8YFLogxK
U2 - 10.1378/chest.119.6.1878
DO - 10.1378/chest.119.6.1878
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C2 - 11399718
AN - SCOPUS:0034892334
SN - 0012-3692
VL - 119
SP - 1878
EP - 1885
JO - Chest
JF - Chest
IS - 6
ER -