Dynamic measurement of regional ventilation and perfusion of the lung with Xe-133

A method for measuring regional distribution of ventilation and perfusion with Xe-133 during tidal breathing was developed with normal subjects, and compared with current breath-holding techniques in patients and in animals. Normal values for a ventilation index during washin, a perfusion index, and a washout slope index were determined in both supine and upright normal subjects. Comparisons of tidal-breathing and breath-holding measurements in patients with localized bullous disease of the lung showed roughly equal values for perfusion index by the two methods, but the tidal-breathing method was more sensitive to abnormalities in ventilation index. During occlusion of branches of the pulmonary artery in animals, the tidal-breathing and breath-holding methods were again comparable in the measurement of perfusion indices, but the tidal-breathing method provided a more sensitive assessment of ventilatory changes due to partial bronchial occlusion in animals. This technique appears superior to standard methods and is well suited to dynamic measurement of regional ventilation and perfusion in a number of experimental and clinical circumstances.