X-ray Densitometry in the Study of Pulmonary Ventilation and the Pulmonary Circulation

Abstract

1. A technique is described for recording variation in the radiographic density of the lung during respiration and with pulmonary vascular pulsation. 2. Some evidence is produced to suggest that by this method it is possible to study pulmonary ventilation on a regional basis. In the normal and in generalised airways obstruction there is a close similarity between the spirometer and density records. Localised abnormalities of the ventilation can also be demonstrated by comparative studies. 3. Analysis of the pulsation records suggest that they show regional changes in volume of blood within the lungs. Normally there is a similarity between the pulsation record and the pulmonary artery pressure record. Records obtained during the Valsalva manoeuvre, premature systolic contraction and a variety of abnormal conditions have been demonstrated and their significance discussed. 4. To date, the method allows qualitative comparison of corresponding areas of the two lungs. More work is being done to put it on a quantitative basis.