In:
Journal of Applied Physiology, American Physiological Society, Vol. 104, No. 4 ( 2008-04), p. 1177-1184
Abstract:
Computer tomography (CT) imaging techniques permit the noninvasive measurement of regional lung function. Regional specific volume change (sVol), determined from the change in lung density over a tidal breath, should correlate with regional ventilation and regional lung expansion measured with other techniques. sVol was validated against xenon (Xe)-CT-specific ventilation (sV̇) in four anesthetized, intubated, mechanically ventilated sheep. Xe-CT used expiratory gated axial scanning during the washin and washout of 55% Xe. sVol was measured from the tidal changes in tissue density (H, houndsfield units) of lung regions using the relationship sVol = [1,000(Hi − He)]/[He(1,000 + Hi)] , where He and Hi are expiratory and inspiratory regional density. Distinct anatomical markings were used to define corresponding lung regions of interest between inspiratory, expiratory, and Xe-CT images, with an average region of interest size of 1.6 ± 0.7 ml. In addition, sVol was compared with regional volume changes measured directly from the positions of implanted metal markers in an additional animal. A linear relationship between sVol and sV̇ was demonstrated over a wide range of regional sV̇ found in the normal supine lung, with an overall correlation coefficient ( R 2 ) of 0.66. There was a tight correlation ( R 2 = 0.97) between marker-measured volume changes and sVol. Regional sVol, which involves significantly reduced exposure to radiation and Xe gas compared with the Xe-CT method, represents a safe and efficient surrogate for measuring regional ventilation in experimental studies and patients.
Type of Medium:
Online Resource
ISSN:
8750-7587
,
1522-1601
DOI:
10.1152/japplphysiol.00212.2007
Language:
English
Publisher:
American Physiological Society
Publication Date:
2008
detail.hit.zdb_id:
1404365-8
SSG:
12
SSG:
31
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