CT-guided percutaneous fine-needle aspiration biopsy of small (≤1-cm) pulmonary lesions

PURPOSE: To determine the accuracy of percutaneous computed tomography (CT)-guided fine-needle aspiration biopsy (FNAB) of small (less than or equal to1.0-cm in diameter) pulmonary lesions. MATERIALS AND METHODS: Sixty-one patients (34 men and 27 women) 21-89 years old (mean age, 61.3 years) with lung nodules 1.0 cm or smaller underwent CT-guided transthoracic FNAB. Fifty-seven of the 61 patients had an underlying primary malignancy. Maximum nodule diameters were 0.5-0.7 cm in 10 patients and 0.8-1.0 cm in 51 patients. Cytopathologic evaluation of FNAB samples was immediate in all patients. Sensitivity and accuracy were calculated, and each case was reviewed for complications, including pneurnothorax and thoracostomy tube insertion. Four patients were not included in our statistical analysis because of a lack of follow-up information. RESULTS: FNAB samples were adequate for diagnosis in 47 (77%) of 61 patients. Diagnoses were malignancy (n = 29) or suspected malignancy (n = 3) in 52% (n = 32) and benign or atypical findings in 25% (n = 15). Findings were nondiagnostic in 23% (n = 14). Of the 29 patients without evidence of malignancy, 25 had follow-up findings available. Follow-up included chest CT in 16 patients and surgical resection in nine. Four patients were not included in statistical analysis because of a lack of follow-up information. Overall sensitivity was 82% (32 of 39); specificity, 100% (18 of 18); and diagnostic accuracy, 88% (50 of 57) on the basis of 57 patients being evaluable. Results for 47 0.8-1.0-cm lesions were considerably better (sensitivity, 88%; accuracy, 92%) than those for 10 0.5-0.7-cm lesions (sensitivity, 50%; accuracy, 70%). Sensitivity (75% vs 87%) and accuracy (87% vs 89%) also improved when comparing subpleural (less than or equal to1.0 cm from pleural surface, n = 30) with deeper (>1 cm from pleural surface, n = 27) pulmonary lesions, but the improvement did not indicate statistical significance. Core biopsy did not reveal malignancy in any of the nine patients in whom preliminary cytologic results were inconclusive and did not improve diagnostic yield. Thirty-eight (62%) patients had pneumothorax, with 19 (31%) requiring thoracostomy tube placement. CONCLUSION: CT-guided FNAB of pulmonary lesions 1.0 cm or smaller can yield high diagnostic accuracy rates approaching those of larger lesions; FNAB of 0.8-1.0-cm lesions that are not subpleural offers the best opportunity for success. (C) RSNA, 2002.