Hydrostatic versus oleic acid-induced pulmonary edema: high-resolution computed tomography findings in the pig lung.
OBJECTIVE
We evaluated the differences between combined hydrostatic and hypervolemic edema and oleic acid-induced edema on high-resolution computed tomography (HRCT) scans.


METHODS
Twelve anesthetized and ventilated pigs were studied. Hydrostatic edema was induced by ligation of the abdominal aorta and infusion of normal saline (n = 4); permeability edema was induced by intravenous injection of oleic acid (n = 4). Four pigs were studied as normal controls. Serial scans were obtained before and after induction of edema at a constant position in the caudal lobe of the lung. The distribution of edema was assessed visually. Cross-sectional areas (CSAs) of the pulmonary artery and vein were measured both at the lobar and segmental levels.


RESULTS
Gravity-dependent opacity, peribronchovascular fluid collection, prominent centrilobular core, thickening of the interlobular septa, and air-space consolidation at the dependent site were the sequential HRCT findings of hydrostatic edema. Randomly distributed, diffuse patchy high attenuation areas with a tendency for predilection in the subpleural and peripheral areas of the secondary lobule were the findings of oleic acid-induced edema. Hydrostatic edema increased the mean CSAs of the lobular vein by 137.8% +/- 78.7, but oleic acid edema decreased the mean CSAs by 33.2% +/- 22.7. Changes in the mean CSAs of the pulmonary arteries were not significant. The mean vein-to-artery ratio increased significantly in hydrostatic edema but decreased in oleic acid edema.


CONCLUSIONS
HRCT findings for hydrostatic and oleic acid-induced pulmonary edema differed both in distribution of edema and in pulmonary vascular response.
Im
J G
JG
Department of Radiology, Seoul National University Hospital, South Korea.
Yu
Y J
YJ
Ahn
J M
JM
Han
M C
MC
Oh
Y S
YS
D000818:Animals; D016009:Chi-Square Distribution; D004195:Disease Models, Animal; D006874:Hydrostatic Pressure; D008168:Lung / Q000000981:diagnostic imaging*; D019301:Oleic Acid; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011654:Pulmonary Edema / Q000000981:diagnostic imaging* / Q000209:etiology*; D011667:Pulmonary Veins / Q000000981:diagnostic imaging; D012016:Reference Values; D018709:Statistics, Nonparametric; D013552:Swine; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data
D019301:Oleic Acid