Magnetic resonance imaging-guided biopsies of the petrous apex and petroclival region

Objective: To analyze the advantages in safety and precision of biopsies of the petrous apex and petroclival region using open magnetic resonance imag ing (MRI). Setting: The University of Leipzig Medical Center. Patients: Biopsies were taken in 13 patients with tumors of the petrous ape x and petroclival region. Intervention: With the patient in the 0.5-T intraoperative MRI system (Sign a SP; General Electric Medical Systems, Boston, MA, U.S.A.), biopsies were taken from the petrous apex and the petroclival region under imaging contro l by transseptal, transsphenoidal access. The region of interest was approa ched with a virtual pointer (Flashpoint Position Encoder: Image Guided Tech nologies, U.S.A.) and marked with a gadolinium-filled pointer. Results: In all patients, the authors obtained enough tissue for histologic study, which also proved to be the suspected tumor. One patient had a bone cyst, another had a malignant lymphoma. and another two a cholesterol gran uloma originating from the petrous apex. Three other patients had metastase s (carcinoma of the breast, bronchial carcinoma, and unknown origin). Three patients had a meningioma, and another three a chordoma. The authors did n ot see any postoperative complications. Conclusions: In the authors' experience. the transsphenoidal access is, fav orable for approaching and sampling lesions of the petrous apex and the pet roclival region. This route, however. is disadvantageous because the course of the internal carotid artery and the brainstem narrow the surgical space to the petrous apex. Open MRI in these cases is very useful because it all ows a safe approach to the tumor by navigation and by visualizing the anato mic structures in real-time imaging.