Radiological findings of patients with primary spontaneous pneumothorax (PSP) undergoing surgery have not been well analyzed. The aim of this study was to evaluate the accuracy of imaging studies for predicting the presence of emphysema-like changes (ELCs) detectable during surgery.Ninety-three PSP patients who underwent surgery from September 2005 to October 2009 were included in the study. We analyzed preoperative chest radiographic and computed tomographic (CT) findings, and compared the findings with intraoperative detection of ELCs. Chest radiographic findings were analyzed by classifying the PSP size into three categories: small, moderate, and complete.Seventy-six of the 93 patients (82%) had ELCs detected during surgery. The size of the PSP on a radiograph was significantly correlated with the presence of ELCs (p=0.0121). Preoperative CT revealed 64 of the 76 ELCs (sensitivity, 84%; specificity, 100%; accuracy, 87%). Twenty-nine patients without ELCs detected by preoperative CT were analyzed separately. In this group, a larger PSP size also increased the likelihood of ELCs being present (p=0.0049). Seven patients (8%) experienced a recurrence after surgery. No factor could significantly predict recurrence.Chest CT analysis alone was associated with a false-negative rate of about 15% for ELCs. Combining the analysis of chest radiographic and CT findings could improve sensitivity.