Lung density patterns in a group of randomly selected, normal individuals were determined by computed tomography, using two methods: one measuring the density of the peripheral lung (parenchyma), and the other determining the density of the whole lung field. The effects of body position and respiratory phase, as well as patient age were assessed. The potential use for this information in clinical settings and in physiological investigation is suggested.

No abstract

Preliminary work has shown that normal lungs have predictable CT patterns and density ranges. In emphysema, there are irregular zones of extremely low density as well as an overall low mean density. CT appears to have considerable potential for early detection of pulmonary emphysema and characterization of the degree of involvement. CT can also be useful in the study of physiological phenomena such as regional blood flow.

The epicardial fat pad sign (EFPS) has been useful in the diagnosis of pericardial effusion on plain frontal and lateral chest radiographs. In this series of 100 cases, including patients with small pericardial effusions, it was positive in 52% of cases, being seen on the lateral view in 41%, on the frontal view in 23%, and on both views in 12%. The authors consider this sign to be the most reliable plain-radiograph finding in the diagnosis of pericardial effusion.

Acute experimental pulmonary arterial occlusions were produced in 5 dogs. The chest was subsequently imaged with computed tomography (CT), 99mTc-MAA scintigraphy, and plain radiography. Gamma images revealed all 6 lesions, and plain radiographs were uniformly negative. Enhanced CT scans demonstrated 3 of 5 lesions, and unenhanced scans revealed 1 of 6. CT findings were variable.