Lung scan utilization in the diagnosis of pulmonary disease.

Radioisotope131 I scanning of the lungs has been used primarily as a diagnostic tool in suspected pulmonary embolism. The present study has analyzed 71 consecutive scans in relation to independent observer grading, interpretation of the scan versus the posterior-anterior chest film and lung scan grade versus multiple pulmonary function parameters. The scans were done in patients with obstructive pulmonary disease (emphysema, bronchitis, asthma, and bronchiectasis) none of whom had overt or suspected pulmonary embolism. Two independent observers graded the scans on a 1 to 6 unit scale. There was agreement within one unit in 73 percent of the scans. There was matching of interpretation (normal versus abnormal) between the posterior-anterior chest x-ray film (interpreted by radiologist) and the scan (interpreted by the two observers) in 76 percent of the cases. There was significant correlation between lung scan grade and FEVo 5, FEVl 0, FEV2 0, FEY3 0, FEV25 15, FEVZOO 1200, and DLcdTLC ratio. The highest correlation (0.643) was between the lung scan abnormality and FEVI o. This study demonstrates direct relationships between abnormal pulmonary function and abnormal lung scanning in chronic obstructive pulmonary disease and infers a negation of the effectiveness of lung scans in diagnosing pulmonary embolism in the face of underlying pulmonary disease which is so prevalent today.