Dynamic changes in lung water density and volume following supine body positioning.

Autor: Goodhart, Thomas, Seres, Peter, Grenier, Justin, Keen, Christopher, Stobbe, Rob, Thompson, Richard B.
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Zdroj: Magnetic Resonance in Medicine; Jun2024, Vol. 91 Issue 6, p2613-2620, 9p
Abstrakt: Purpose: Measure the changes in relative lung water density (rLWD), lung volume, and total lung water content as a function of time after supine body positioning. Methods: An efficient ultrashort-TE pulse sequence with a yarnball k-space trajectory was used to measure water density-weighted lung images for 25 min following supine body positioning (free breathing, 74-s acquisitions, 3D images at functional residual capacity, 18 time points) in 9 healthy volunteers. Global and regional (10 chest-to-back positions) rLWD, lung volume, and total lung water volume were measured in all subjects at all time points. Volume changes were validated with a nitrogen washout study in 3 participants. Results: Global rLWD increased significantly (p=0.001) from 31.8±5.5% to 34.8±6.8%, while lung volumes decreased significantly (p<0.001) from 2390±620mL to 2130±630mL over the same 25-min interval. Total lung water volume decreased slightly from730±125mL to 706±126mL (p=0.028). There was a significant chest-to-back gradient in rLWD (20.7±4.6% to 39.9±6.1%) at all time points with absolute increases of 1.8±1.2% at the chest and 5.4±1.9% at the back. Nitrogen washout studies yielded a similar reduction in lung volume (12.5±0.9%) and time course following supine positioning. Conclusion: Lung volumes during tidal breathing decrease significantly over tens of minutes following supine body positioning, with corresponding increases in lung water density (9.2±4.4% relative increase). The total volume of lung water is slightly reduced over this interval (3.3±4.0% relative change). Evaluation of rLWD should take time after supine positioning, and more generally, all sources of lung volume changes should be taken into consideration to avoid significant bias. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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