MR-guided Needle Aspiration Biopsies of Hepatic Masses Using a Closed Bore Magnet

Purpose: Our purpose was to assess the efficacy of MR-guided biopsies with a conventional superconducting MR scanner and describe the techniques used to achieve successful results.

Method: Fourteen biopsies were completed under MR guidance in 11 patients. Seven patients with previously detected lesions were referred for biopsy under MR guidance when hepatic lesions were identified by MRI but not with prebiopsy noncontrast CT or ultrasound (US). Additionally referred for MR-guided biopsy were four patients in whom previous CT- or US-guided biopsies of focal lesions were nondiagnostic. A 22 gauge MR-compatible needle was used 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: Thirteen of 14 MR-guided biopsies (93%) were diagnostic. Hepatocellular carcinoma was confirmed in 6 of 11 lesions suspected of representing hepatoma. One lesion, in a patient treated with chemoembolization, demonstrated necrotic material. One lesion yielded nondiagnostic material despite repeated visualization of the needle tip in the target lesion. Three lesions demonstrated metastatic carcinoma. Benign hepatocytes were detected in three biopsy specimens. Seven of the lesions that were successfully biopsied measured < 2.5 cm in diameter.

Conclusion: With use of a closed bore 1.5 T system, diagnostic MR-guided needle aspiration biopsies of hepatic masses and subcomponents, including small lesions (< 2.5 cm), can be successfully obtained.