Conference proceeding
Xenon gas flow patterns evaluated by high-speed multi-row detector CT
Proceedings of SPIE, Vol.5369(1), pp.89-99
Medical Imaging 2004: Physiology, Function, and Structure from Medical Images
04/30/2004
DOI: 10.1117/12.535845
Abstract
Regional lung ventilation can be measured via Xenon-enhanced computed tomography (Xe-CT) by determining washin (WI) and washout (WO) rates of stable Xe. It has been assumed that WI = WO, ignoring Xe solubility in blood and tissue and then other geometric issues. We test this by measuring WO-WI in lung by Xe-CT. Also, we investigate the effect of tidal volume (TV) and end inspiratory (EI) vs end expiratory (EE) scan gating on WO and WI measurements. 3 anesthetized, supine sheep were scanned using multidetector-row computed tomography (MDCT). Imaging was gated to both EE and EI during a WI (33 breaths) and WO (20 breaths) maneuver using 55% Xe for WI and room air for WO. Time constants (TCs) of Xe WI and WO were obtained by exponential fitting. WO and WI TCs were compared: 1) apex and base 2) dependent, middle, and nondependent 3) EE and EI 4) three TVs. The vertical gradient of WO-WI showed WO > WI in dependent vs non-dependent regions. WO-WI in both dependent and nondependent region at the lung base and apex was larger when measured at EE compared to EI. As TV increases, the global WO-WI difference decreased. TV showed greater influence on WO than WI. Xe WO was longer than WI possibly reflecting Xe solubility in blood and tissue. Higher TVs and gating to EE provided greater effects on WO than WI TCs which may relate to the number of partial volumed conducting airways contributing to the regional voxel-based measures. We conclude that WO mode is more susceptible to errors caused by either xenon solubility or tidal volume than WI mode and EE scanning may more accurately reflect alveolar ventilation.
Details
- Title: Subtitle
- Xenon gas flow patterns evaluated by high-speed multi-row detector CT
- Creators
- Deokiee Chon - University of IowaKen C Beck - University of IowaHidenori Shikata - University of IowaOsama I Saba - University of IowaBrett A Simon - Johns Hopkins UniversityChulho Won - University of IowaEric A Hoffman - University of Iowa
- Resource Type
- Conference proceeding
- Publication Details
- Proceedings of SPIE, Vol.5369(1), pp.89-99
- Conference
- Medical Imaging 2004: Physiology, Function, and Structure from Medical Images
- DOI
- 10.1117/12.535845
- ISSN
- 0277-786X
- Language
- English
- Date published
- 04/30/2004
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiology; Internal Medicine
- Record Identifier
- 9984196984402771
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