BACKGROUND Spontaneous pneumothorax (SP) is a common disease of unknown cause often attributed to rupture of a subpleural bulla or bleb [in this study described as emphysema-like changes (ELC)]. Treatment of SP varies from conservative (rest) to aggressive (surgery). Patients with bullae >2 cm diameter, found either by chest roentgenogram or during thoracoscopy, are often treated surgically (bullectomy and pleurectomy, or abrasion). Thoracoscopy is frequently used as the method of choice to select patients for surgery. With the recent introduction of video-assisted thoracoscopy (VAT), it is now possible to combine a diagnostic and therapeutic procedure. However, to do this general anesthesia and a fully equipped operating theater are needed. Proper selection of patients for this costly and time-consuming procedure is necessary. We evaluated whether standard computed tomography (CT) is appropriate for selection of patients with SP who are candidates for surgical intervention. METHODS In 43 patients with SP, CT was performed after re-expanding the lung by suction through a chest tube if the lung was completely collapsed. After <48 hours VAT under general anesthesia was performed. All CT scans were scored by two investigators who were not informed about the VAT findings or the outcome of the patient. CT findings and VAT findings were compared. RESULTS In 16 patients (37%), CT scans of the affected lung were considered normal, while in 13 patients (30%) ELCs >/=2 cm were seen and in 14 patients (33%) ELCs <2 cm were found. VAT showed a normal lung in 11 patients (26%), in 24 patients ELCs >/=2 cm were seen, and in 8 patients ELCs <2 cm were present. Of these 32 patients, in 18 bullous degeneration of the apex of the upper lobe was found. Of the 24 patients with ELCs >/=2 cm detected during VAT, 13 were detected by CT. In no patient were ELCs >/=2 cm seen on CT scans that were not detected during VAT. The sensitivity of CT for ELCs >/=2 cm is 54%, and the specificity is 100%. The positive predictive value is 100%; the negative predictive value is 63%. CONCLUSIONS CT detects ELCs >/=2 cm in 54% of the patients in whom VAT shows these abnormalities. If interventional therapy is deemed appropriate for first time or recurrent SP, VAT should be used since it is superior to CT in demonstrating the presence, number, and size of ELCs.