[Usefulness CT-guided F.N.A.C. in the diagnosis of mediastinal lesions]

Objective To evaluate the diagnostic accuracy of the percutaneous fine needle aspiration cytology (FNAC) for mediastinal lesions by using histology or follow-up clinical diagnosis as gold standard. Patients and Methods CT-guided percutaneous FNAC was performed on 131 patients with mediastinal lesions. Helical CT was used with 3–10mm image thickness range and low radiation dose (40mAs, 120kV). Samples were immediately examined by a cytologist to determine if they were representative. Histological samples were obtained by means of biopsy or resection specimens in 73 patients and clinical follow-up in 50. Results The material was satisfactory for diagnosis in 126 patients (95.2 %), in whom 103 lesions (78.6%) were considered malignant (62 primary tumours and 41 metastases) and 23 (17.6%) benign. In the 123 patients with clinical monitoring or pathological diagnosis, using FNAC led to the identification of malignancy with a sensitivity of 95.2 % (95%CI: 89.2–97.9%), specificity 84.2% (95%CI: 62.4–94.5%), positive predictive value 97.1% (95%-CI: 91.7–99.0%), negative predictive value 76.2% (95%CI: 54.9–89.4%), likelihoodratio positive 6.03 (95%CI: 2.13–17.05) and accuracy 93.5% (95%CI: 87.7–96.7%). Pneumothorax was the most frequent complication (3 cases). There was good agreement between the cytological findings and the histological findings, not only for malignant lesions (kappa coefficient: 0.641) but also for benign (kappa 0.607). Conclusions CT-guided percutaneous FNAC is a safe and effective technique for the diagnosis of the mediastinal masses, with a high diagnostic yield for malignancy depicting.