The Value of the Lateral Chest Roentgenogram in the Diagnosis of Pulmonary Venous Hypertension

Abstract

Dilatation of upper lobe veins is a reliable roentgen sign of pulmonary venous hypertension (1, 3–9). Largely dilated upper lobe veins are easy to detect on routine chest roentgenograms. Minimal dilatation, however, is difficult to identify on the postero-anterior or anteroposterior projection because of overlying arterial branches. Due to anatomical distribution, the anterior vein of the right upper lobe is easily identifiable on the left lateral projection, especially when pulmonary venous hypertension is present. The recognition of dilated upper lobe veins on the lateral view leads to early radiological diagnosis of abnormal pulmonary venous pressure. Lack of knowledge of the roentgen anatomy of upper lobe vessels will limit radiological diagnostic ability. The roentgen anatomy of upper lobe vessels is not well described in the literature. To the author's knowledge, the anatomical relationship between upper lobe veins and arteries and their distribution, especially on lateral chest roentgenograms, has not been published. To clarify this, the upper lobe vessels were studied in normal patients and those with mitral heart disease by lateral laminagrams of the chest and selective right pulmonary angiograms on the lateral projection. In order to determine the value of the lateral projection in the diagnosis of pulmonary venous hypertension, routine left lateral views of plain chest films were also studied in 68 patients with proved rheumatic mitral heart disease, including 47 cases of pure mitral stenosis, 13 cases of mitral stenosis and mitral insufficiency, and 8 cases of combined mitral and aortic valvular disease. Radiological Anatomy Though the veins are not easily distinguishable from arteries on the routine chest roentgenograms, knowledge of roentgen anatomy of pulmonary vessels and experience will assist the identification. The pulmonary veins lie inferoanterior to the bronchi, while the arteries are usually superoposterior to it. The pulmonary artery generally divides into branches corresponding to the division of the bronchi and accompanying the branches of a bronchopulmonary segment. The veins, however, are more semivertical in position and intersegmental in distribution, with rather narrow angled branching. The veins are also frequently less prominent than the arteries on the normal radiographs. The upper lobe veins lie more lateral and inferior to the corresponding arteries on the frontal-projection chest roentgenogram. They are occasionally overlapped with the arterial branches and difficult to identify on this projection. On the left lateral view the upper lobe veins are anteroinferior to the corresponding arteries. Though Steinbach et al. (8) stated that only the lower lobe veins can be identified on the lateral view, the anterior vein of right upper lobe is usually clearly visible (Figs. 1–3).