Perfusion scans are accurate predictors of postoperative lung function. There are few previous studies aimed at predicting the postoperative exercise capacity using the perfusion scanning and those that did reported contradictory results.

We prospectively studied the preoperative spirometric, exercise tests and perfusion scans from in 49 consecutive patients who were admitted to Inha University Hospital with surgically resectable lung cancer from Jan. 1998 to Jun. 1999 29 patients who had any condition affecting the lung function and exercise capacity, or refused a surgical resection or a follow-up study were excluded. Spirometric and exercise tests were performed 6 months after operation in 20 patients.

The predicted postoperative FEV₁, FVC and TLC correlated well with the following corresponding postoperative values : γ_s and p value, 0.809 and 0.000 for the FEV₁ ; 0.895 and 0.000 for the FVC ; 0.741 and 0.006 for the TLC, respectively. The measured postoperative exercise values were slightly higher than the postoperative exercise values predicted, VO_2max and Wr_max, were as 112% of VO_2max predicted and 119% of WR_max predicted. The change in FEV₁, FVC and TLC had a weak correlation with the change in VO_2max and WR_max.

The perfusion scan was a useful tool for predicting the postoperative exercise capacity. However, they had a tendency to underestimate the exercise capacity, especially in the patients who had a pneumonectomy. A weak correlation between the change in lung function and exercise capacity was obseved.