Journal article
Effect of low-xenon and krypton supplementation on signal/noise of regional CT-based ventilation measurements
Journal of applied physiology (1985), Vol.102(4), pp.1535-1544
2007
DOI: 10.1152/japplphysiol.01235.2005
PMID: 17122371
Abstract
Xenon computed tomography (Xe-CT) is used to estimate regional ventilation by measuring regional attenuation changes over multiple breaths while rebreathing a constant Xe concentration ([Xe]). Xe-CT has potential human applications, although anesthetic properties limit [Xe] to <or=35%. We investigate effects of lower [Xe], including a low [Xe]-krypton (Kr) combination, on time constant (TC) determination. Six anesthetized sheep were scanned prone and supine using multidetector row CT. Lungs were imaged by respiratory gating during washin of a 30%, 40%, 55% Xe, and a 30% Xe/30% Kr mixture. Using Kr avoids unwanted effects of Xe. Mean TCs, coefficients of variation (CV), and half confidence intervals (CI)/mean served as indexes of sensitivity to noise. Mean supine and prone TCs of three [Xe] values were not significantly different. Average CVs of TCs increased from 57% (55% Xe), 58% (40% Xe), and 73% (30% Xe) (P < 0.05: paired t-tests; 30% Xe vs. higher [Xe]). Monte Carlo simulation indicated a CV based on inherent image noise was 8% for 55% Xe and 17% for 30% Xe (P < 0.05). Adding 30% Kr to 30% Xe gave a washin signal equivalent to 40% Xe. Half CI/mean using the 30% Xe/30% Kr mixture was not significantly different from 55 and 40% Xe. Although average TCs were not affected by changes in [Xe], the higher CV and half CI/mean suggested reduced signal-to-noise ratio at the 30% [Xe]. The 30% Xe/30% Kr mixture was comparable to that of 40% Xe, providing an important agent for CT-based assessment of regional ventilation in humans.
Details
- Title: Subtitle
- Effect of low-xenon and krypton supplementation on signal/noise of regional CT-based ventilation measurements
- Creators
- Deokiee Chon - University of IowaKenneth C Beck - University of IowaBrett A Simon - Johns Hopkins UniversityHidenori Shikata - University of IowaOsama I Saba - University of IowaEric A Hoffman - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Journal of applied physiology (1985), Vol.102(4), pp.1535-1544
- Publisher
- American Physiological Society
- DOI
- 10.1152/japplphysiol.01235.2005
- PMID
- 17122371
- ISSN
- 8750-7587
- eISSN
- 1522-1601
- Language
- English
- Date published
- 2007
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiology; Internal Medicine
- Record Identifier
- 9984197144602771
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