Differences in regional wash-in and wash-out time constants for xenon-CT ventilation studies

Deokiee Chon; Brett A Simon; Kenneth C Beck; Hidenori Shikata; Osama I Saba; Chulho Won; Eric A Hoffman

doi:10.1016/j.resp.2005.06.003

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Differences in regional wash-in and wash-out time constants for xenon-CT ventilation studies

Journal article

Peer reviewed

Differences in regional wash-in and wash-out time constants for xenon-CT ventilation studies

Deokiee Chon, Brett A Simon, Kenneth C Beck, Hidenori Shikata, Osama I Saba, Chulho Won and Eric A Hoffman

Respiratory physiology & neurobiology, Vol.148(1), pp.65-83

2005

DOI: 10.1016/j.resp.2005.06.003

PMID: 16061426

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Abstract

Xenon-enhanced computed tomography (Xe-CT) has been used to measure regional ventilation by determining the wash-in (WI) and wash-out (WO) rates of stable Xe. We tested the common assumption that WI and WO rates are equal by measuring WO–WI in different anatomic lung regions of six anesthetized, supine sheep scanned using multi-detector-row computed tomography (MDCT). We further investigated the effect of tidal volume, image gating (end-expiratory EE versus end-inspiratory EI), local perfusion, and inspired Xe concentration on this phenomenon. Results: WO time constant was greater than WI in all lung regions, with the greatest differences observed in dependent base regions. WO–WI time constant difference was greater during EE imaging, smaller tidal volumes, and with higher Xe concentrations. Regional perfusion did not correlate with WI–WO. We conclude that Xe-WI rate can be significantly different from the WO rate, and the data suggest that this effect may be due to a combination of anatomic and fluid mechanical factors such as Rayleigh–Taylor instabilities set up at interfaces between two gases of different densities.

Airway conductance

Computed tomography

Inert gas dilution

Multi-detector row CT

Pulmonary imaging

Regional lung ventilation measurements

Xenon

Details

Title: Subtitle: Differences in regional wash-in and wash-out time constants for xenon-CT ventilation studies
Creators: Deokiee Chon - University of Iowa
Brett A Simon - Johns Hopkins University
Kenneth C Beck - University of Iowa
Hidenori Shikata - University of Iowa
Osama I Saba - University of Iowa
Chulho Won - University of Iowa
Eric A Hoffman - University of Iowa
Resource Type: Journal article
Publication Details: Respiratory physiology & neurobiology, Vol.148(1), pp.65-83
Publisher: Elsevier B.V
DOI: 10.1016/j.resp.2005.06.003
PMID: 16061426
ISSN: 1569-9048
eISSN: 1878-1519
Language: English
Date published: 2005
Academic Unit: Roy J. Carver Department of Biomedical Engineering; Radiology; Internal Medicine
Record Identifier: 9984196994702771

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