Alveolar volume determined by single-breath helium dilution correlates with the high-resolution computed tomography-derived nonemphysematous lung volumevan der Lee, I., van Es, H. W., Noordmans, H. J., van den Bosch, J. M. M. & Zanen, P., 2006, In : Respiration. 73, 4, p. 468-473 6 p.
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Background: The alveolar volume (V(A)), determined by single-breath helium dilution, is a measure for the total lung capacity (TLC) that is very sensitive to ventilatory disturbances. In chronic obstructive pulmonary disease (COPD), the emphysematous lung parts are less accessible to test gas; therefore, the V(A) is smaller than TLC measured by multiple-breath helium dilution (TLC(He)). Objectives: The aim of this study was to investigate whether the V(A) represents the nonemphysematous lung parts. Methods: We measured V(A) as part of the diffusing capacity for carbon monoxide (DL(CO)), TLC He and spirometry in 50 patients with COPD. High-resolution computed tomography (HRCT) scans of all subjects were analyzed with the density mask method, where parts with an attenuation of less than -950 Hounsfield units were considered as emphysematous. Results: A strong correlation was observed between the V(A) (mean 5.2 liters) and nonemphysematous HRCT lung volume (mean 5.2 liters, r(2) = 0.9) and between the TLC He (mean 6.6 liters) and total HRCT lung volume (mean 6.4 liters, r(2) = 0.9). Bland-Altman plots showed considerable disagreement between the V(A) and the nonemphysematous HRCT lung volume. A weak correlation between the forced expiratory volume in 1 s (mean 46% predicted) and DL(CO) (mean 46% predicted) versus the HRCT emphysema ratio (non-emphysematous/ total HRCT lung volume) was observed (R(2) = 0.3 and 0.3, respectively). Conclusion: We concluded that the V(A) correlates with the nonemphysematous HRCT lung volume, although the two measurements are not equivalent, possibly due to technical factors. Copyright (C) 2006 S. Karger AG, Basel.
|Number of pages||6|
|Publication status||Published - 2006|
- high-resolution computed tomography, emphysema, chronic obstructive pulmonary disease, alveolar volume, density mask, PULMONARY-FUNCTION TESTS, AIRWAY-OBSTRUCTION, EMPHYSEMA, CT, DENSITY, MORPHOMETRY, ATTENUATION, AREAS