Characterization of the Shape and Location of Perfusion Defects in Certain Pulmonary Diseases

Abnormal lung scans obtained from patients with pulmonary embolism, pulmonary tuberculosis, chronic obstructive pulmonary disease and carcinoma of the lung were analyzed in an attempt to classify the location and types of perfusion defects. Peripheral concave defects were most common in pulmonary embolism (72 per cent of cases), and a diffuse type of defect was common in pulmonary tuberculosis (92 per cent) and chronic obstructive pulmonary disease (77 per cent). Areas of complete absence of perfusion were seen in 92 per cent of patients with carcinoma of the lung. Although concave defects were seen in pulmonary tuberculosis and chronic obstructive pulmonary disease, they were only half as frequent as in pulmonary embolism.