Ventilation perfusion scanning in carcinoma of the bronchus

Ventilation perfusion studies were performed on 26 patients with known or suspected carcinoma of the bronchus. Regional figures for relative perfusion, ventilation and ventilation perfusion ratios were obtained using a small digital computer interfaced to a gamma scintillation camera. All the patients who had a successful resection had a relative perfusion of their affected lung of more than 33%. All the patients who were bronchoscopically inoperable and three of four patients found unresectable at thoracotomy had a relative perfusion of less than 33%. Relative ventilation did not produce such a separation. Ventilation perfusion ratios outside the normal range for a zone were also an indication of inoperability. Perfusion defects were seen in 48% of the contralateral lungs and ventilation defects in 78%. It is suggested that ventilation perfusion studies can: supplement routine spirometry test by giving an estimation of regional lung function, provide an indication of unresectability, occasionally reveal the site of an occult carcinoma of the bronchus.