MR-GUIDED NEEDLE ASPIRATION BIOPSIES OF HEPATIC MASSES USING A CLOSEDBORE MAGNET

Purpose: Our purpose was to assess the efficacy of MR-guided biopsies with a conventional superconducting MR scanner and describe the techni ques used to achieve successful results. Method: Fourteen biopsies wer e completed under MR guidance in 11 patients. Seven patients with prev iously detected lesions were referred for biopsy under MR guidance whe n hepatic lesions were identified by MRI but not with prebiopsy noncon trast CT or ultrasound (US). Additionally referred for MR-guided biops y were four patients in whom previous CT- or US-guided biopsies of foc al lesions were nondiagnostic. A 22 gauge MR-compatible needle was use d in each case. Lesions ranged in size from 8 to 32 mm. Eleven lesions (eight patients) were suspected of being hepatomas, and three lesions (three patients) were suspected of being metastases. Results: Thirtee n of 14 MR-guided biopsies (93%) were diagnostic. Hepatocellular carci noma was confirmed in 6 of 11 lesions suspected of representing hepato ma. One lesion, in a patient treated with chemoembolization, demonstra ted necrotic material. One lesion yielded nondiagnostic material despi te repeated visualization of the needle tip in the target lesion. Thre e lesions demonstrated metastatic carcinoma. Benign hepatocytes were d etected in three biopsy specimens. Seven of the lesions that were succ essfully biopsied measured <2.5 cm in diameter. Conclusion: With use o f a closed bore 1.5 T system, diagnostic MR-guided needle aspiration b iopsies of hepatic masses and subcomponents, including small lesions ( <2.5 cm), can be successfully obtained.