Small (1.5 cm or less) liver metastases: US-guided biopsy

PURPOSE: To determine the techniques used for and the success of ultrasound (US)-guided biopsy of hepatic metastases 1.5 cm in diameter or smaller. MATERIALS AND METHODS: A computer search of radiology reports identified 29 patients who underwent US-guided biopsy of 30 hepatic masses 1.5 cm in diameter or smaller suspected to be metastases. All 30 lesions were sampled for biopsy with the free-hand technique. Parameters assessed were lesion size and location, needle size, transducer type, number of passes made, cytologic or histologic analysis, and final histologic diagnosis. Biopsies were considered successful if a positive histologic diagnosis of metastasis was made. RESULTS: The mean lesion diameter was 1.3 cm (range, 0.9-1.5 cm). Lesion depth was 3-9 cm (mean, 5 cm). Twenty biopsies were performed with a 22-gauge aspirating needle and analyzed cytologically. An average of 2.7 passes were made per lesion. Phased-array sector transducers were used in 23 lesions. In 28 (93%) lesions and 28 (96%) patients, an adequate specimen was obtained to establish the histologic diagnosis of metastatic disease. CONCLUSION: US appears to be an effective guidance technique for biopsy of small liver metastases.