title: Determination of cardiac size following space missions of different durations: the second manned Skylab mission.
abstract: A simple method to estimate cardiac size from single frontal plane chest roentgenograms has been described. Pre- and postflight chest X-rays from Apollo 17, and Skylab 2 and 3 have been analyzed for changes in the cardiac silhouette size. The data obtained from the computed cardiothoracic areal ratios compared well with the clinical cardiothoracic diametral ratios (r = .86). Though an overall postflight decrease in cardiac size is evident, the mean difference was not statistically significant (n = 8). The individual decreases in the cardiac silhouette size postflight are thought to be due to decrements in intracardiac chamber volumes rather than in myocardial muscle mass.
mesh_terms: D000328:Adult; D002306:Cardiac Volume; D006321:Heart / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D011859:Radiography; D013026:Space Flight; D013997:Time Factors