THE RADIOLOGICAL CHANGES IN PULMONARY VENOUS HYPERTENSION, WITH SPECIAL REFERENCE TO THE ROOT SHADOWS AND LOBULAR PATTERN

Open Access
Publisher Website
Google Scholar
Abstract
The significance and character of the radiological changes caused by pulmonary venous hypertension are discussed, with special reference to the lobular pattern and the root shadows. Venous, mixed, and arterial varieties of pulmonary hypertension are defined. Pulmonary venous hypertension is a state in which the pressure in the pulmonary venous system is high, while the pulmonary vascular resistance remains normal, or increases only slightly, and any rise in pulmonary arterial pressure is passive. The root shadows are of venous type and loss of translucency and opacification of the interlobular septa are likely to be present, especially when the patient is active. Dilatation of the vessels to the upper zone is common, but constriction of those to the lower zone is not amen. Pulmonary mixed hypertension occurs when a raised pulmonary vascular resistance, of spastic or structural origin, complicates pulmonary venous hypertension to produce a disproportionate rise in the pulmonary arterial pressure. The root shadows are of arterial type. Lower zonal constriction is often present and contrasts with the dilatation of the vessels in the upper zone. Opacification of the interlobular septa is often senn, but loss of translucency in the lower zone tends to be less obvious than in pulmonary venous hypertension. Pulmonary arterial hypertension occurs whenever a raised pulmonary arterial pressure occurs without obstruction to pulmonary venous drainage. The radiological changes vary with the underlying cause, but the features of a raised pulmonary venous pressure are absent, constriction of peripheral vessels is not zonal, and the root shadows are of arterial type. Opacification of the interlobular septa causes horizontal lines and a lobular pattern on the radiogram. This opacification may be due to edema, when it is reversible, or to structural changes, when it is irreversible. The appearances caused by pulmonary pleonemia are briefly described and are contrasted with those produced by the three types of pulmonary hypertension.