Prediction of lung cancer spread and functional resectability by 133Xe radiospirometry.

Sixty-six patients with primary lung cancer who underwent thoracotomy were studied to determine the correlations among 133Xe radiospirometry, surgical procedures and histological extension of the lung cancer. Disturbance in the regional perfusion (Q per cent) was more prominent than disturbance of the regional ventilation (V per cent), as the pathological stage and t factor proceeded, while V per cent and Q per cent were disturbed almost equally in relation to the pathological n factor. Lobectomy was impossible in patients with a Q per cent of less than 33 per cent of the total, but low perfusion did not necessarily contraindicate surgery. The predicted postoperative FEV1.0 was calculated according to the equation of (1-b/a x (V per cent or Q per cent)) x (preoperative FEV1.0), where a and b were the number of subsegments in the lung lobes on the involved side and the resected lobe. The predicted and actually measured postoperative FEV1.0 showed significant correlations (less than 0.001) in both equations. We conclude that Q per cent reflects a complex pattern of lung cancer spread more sensitively than does V per cent, and the significance of V per cent and Q per cent in terms of prediction of postoperative EFV1.0 seems to be equivocal.