Transnasal and transsphenoidal MRI-guided biopsies of petroclival tumors

Magnetic resonance Imaging (MRI) allows excellent tissue characterization I n the area of the petroclival region and can depict lesions not visualized with ultrasound or computed tomography (CT). The aim of this study was to d emonstrate the clinical feasibility and utility of an Interactive MR-guidan ce system to target and biopsy tumors in the petroclival region. MRI-guided biopsies of 10 patients with tumors in the clivus and petrous apex were pe rformed In an open 0.5-T MR system. Lesions were targeted through a transsp henoidal or transnasal approach. Imaging during biopsies was achieved by a combination of standard and interactive mode. T1-weighted spin-echo, T2-wei ghted fast spin-echo (FSE), and three-dimensional T1-weighted gradient-echo (GRE) scans (standard mode) were selected to provide optimal tissue charac terization for both the lesion and surrounding structures and varied accord ing to the anatomic site. For interactive Imaging, T1-weighted GRE and T2-w eighted FSE sequences were used. We performed MRI-guided transsphenoidal bi opsies An 10 patients who had lesions identified by CT (n = 5) and/or MRI ( n = 10). The Indications for biopsies were to differentiate between suspect ed malignant processes (n = 4) and benign processes (n = 6). Lesions adjace nt to structures like the internal carotid artery were accurately targeted in particular. All biopsies were performed successfully and were the basis for selection of further treatment. No complications occurred during the pr ocedures. An open MR system allows interactive control of biopsies In the a rea of the petroclival region, providing maximum patient safety and diagnos tic accuracy not possible in other systems. The advantages of MRI tissue ch aracterization are combined with an interactive, one-step method of localiz ation and targeting, as well as tissue sampling. (C) 2001 Wiley-Liss, Inc.