Low-dose MDCT for surveillance of patients with severe homogeneous emphysema after bronchoscopic airway bypass.

ABSTRACT

OBJECTIVE: The purpose of this study was to evaluate the usefulness of low-dose MDCT for radiologic monitoring of patients who have undergone placement of bronchial stents for airway bypass. SUBJECTS AND METHODS: In a prospective study, seven patients underwent MDCT according to a low-dose protocol (40 mAs, 120 kVp) before and after stent placement. The positions of the stents in the segmental bronchi were analyzed and compared with the bronchoscopic findings, which were reference standard. Patency versus lack of patency of stents was classified with five levels of confidence, and a definitive diagnosis was assigned to each stent. Prediction of stent dislodgment, follow-up findings, and complications occurring during the observation period were recorded. Consensus reading was performed by two radiologists. Statistical analysis was conducted by receiver operating characteristic analysis or four-field table. RESULTS: Seven patients underwent implantation of 37 stents (mean, 5 +/- 2 [SD] stents per patient; range, 2-8 stents). The area under the curve for differentiating patent from occluded stents was 0.995 with resulting sensitivity and specificity of 86.5% and 98.1%. The correct diagnosis of patency was established with MDCT for all but one stent (sensitivity, 94.7%; specificity, 100%). Sensitivity and specificity for prediction of dislodgment were 80% and 91%. Five stents were not identified during inspection bronchoscopy but were found in a regular position at MDCT. Three instances of minor bleeding and one of pneumothorax resolved spontaneously. The mean effective dose of the scan was 1.3 +/- 0.6 mSv. CONCLUSION: Low-dose MDCT is feasible for radiologic monitoring after airway bypass procedure.