US-guided percutaneous biopsy of small (<= 1-cm) hepatic lesions

PURPOSE: To determine the accuracy of ultrasonography (US)-guided percutane ous biopsy in diagnosing malignant neoplasms for hepatic lesions 1 cm or sm aller. MATERIALS AND METHODS: In this prospective study, 64 consecutive patients w ith 74 discrete focal hepatic lesions depicted at US were referred for live r biopsy to confirm the exact nature of the lesions. Mean lesion size was 0 .84 cm +/- 0.13 (range, 0.5-1.0 cm). Biopsy was performed with an 18-gauge automated biopsy gun in 46 lesions (once [n = 37], twice [n = 7], three tim es [n = 2]) or a 22-gauge needle in 28 lesions (once [n = 23], twice [n = 4 ], three times [n = 1]). Measures were taken to ensure accurate and effecti ve lesion sampling. The histologic diagnosis of malignant tumor and finding s on follow-up US images of "benign" nodules for 15-39 months were the crit erion standard. RESULTS: No complications occurred. All specimens obtained were sufficient for diagnosis. Histologic examination revealed various types of primary and secondary malignant tumors (n = 44), hemangioma (n = 5), cirrhosis (n = 13 ), focal fatty change (n = 8), focal fatty sparing (n = 2), and abscess (n = 2). The diagnostic discrimination of US-guided biopsy in diagnosing malig nant tumors in these small lesions was sensitivity, 98%; specificity, 100%; positive predictive value, 100%; negative predictive value, 97%; and accur acy, 99%. CONCLUSION: Percutaneous biopsy under US control is highly accurate in prov iding a definitive histologic diagnosis of malignant neoplasms for small he patic lesions if measures for ensuring precise and effective lesion samplin g are taken.