Width Measurements of the Shadow of Right Pulmonary Artery Descending Branch on Medium Size Photofluorograms

Abstract

The width of the shadow of the right pulmonary artery descending branch was measured on medium size photofluorograms (7×7 cm) and on standard chest roentgenograms (35 × 35 cm) obtained from a group of 144 males examined by the two methods in the course of a field survey. For measuring on photofluorograms a reduced scale ruler was employed and this was directly applied to the photofluorographic film using a strong magnifying lens. Failure to measure the diameter of the descending branch occurred with an almost identical frequency on either type of film. A significant correlation (on the 0.1-percent level) was found between the values measured from photofluorograms and those from roentgenograms. Measurements made on photofluorographic films produced a systematic overestimation of the arterial diameter which, however, amounted to only 3% on the average, i.e. less than 0.4 mm. This systematic error may largely be explained by the difference in tube-screen distance. Medium size photofluorography appears to be a useful method for the detection of persons suspected of pulmonary hypertension and for studies on the prevalence of indirect signs of cor pulmonale by assessment of the width of the right descending branch of the pulmonary artery in population groups.