Magnetic resonance imaging-guided fine needle aspiration for the diagnosis of skull base lesions.

Magnetic resonance imaging (MRI)-guided fine needle aspiration was used to obtain tissue from lesions of the skull base for cytologic diagnoses in 14 patients. Our technique utilized a guiding system to enable three-dimensional orientation in a two-dimensional scan and a high nickel content 22 gauge needle to minimize significantly MRI artifact. Needle access to the skull base was provided through a subzygomatic or retromandibular approach. In seven of nine cases an accurate diagnosis was established by this technique and later confirmed by surgical exploration and histologic analysis. Failure to obtain a representative specimen from the lesion occurred in one case and difficulty in interpreting the cytologic features of the tissue was encountered in another case. The indications, limitations, and technical details of the procedure are described.