In vivo measurement of lung volumes in mice.
We describe longitudinal measurements of functional residual capacity (FRC) in breathing mice using a clinical computed tomography (CT) scanner. Lungs of anesthetized mice from the A/J and C3H/HeJ strains were scanned over a 10-s period. Using a fixed threshold for CT density, we could accurately and reproducibly obtain the amount of air in the lungs at FRC, with a 10% coefficient of variation. Total lung volume, and the fractions in left and right lungs, were measured in the two strains from 4 to 12 wk of age. Results show that in both strains the FRC increases only up to 6 wk of age and then remains stable despite a steady increase in body weight. Over this time period, FRC was consistently about 50% greater in the C3H/HeJ strain compared with the A/J strain. The C3H/HeJ strain also has a significantly smaller fraction of the total lung volume in the left lung. We conclude that accurate measurements of FRC in breathing mice can be made using a standard clinical CT scanner. This method may be useful for repeated noninvasive assessment of both structural and functional changes in the lungs of experimental and genetically manipulated mice.
Mitzner
W
W
Johns Hopkins Medical Institutions, Baltimore, Maryland 21205, USA. wmitzner@jhsph.edu
Brown
R
R
Lee
W
W
D000818:Animals; D005541:Forced Expiratory Volume; D008168:Lung / Q000000981:diagnostic imaging / Q000502:physiology*; D051379:Mice; D008809:Mice, Inbred C3H; D008815:Mice, Inbred Strains; D012115:Residual Volume; D014057:Tomography, X-Ray Computed