The value of T2(*)-weighted MR images for the diagnosis of acoustic neuromas

The aim of this study was to evaluate high resolution T2(*)-weighted MRI-in our case a 3D CISS sequence-for the diagnosis of acoustic neuromas. Especi ally to be clarified was if high-resolution T2-weighted sequences can subst itute T1-weighted contrast-enhanced sequences, and in which circumstances t hey can give important additional information when compared with contrast-e nhanced T1-weighted sequences. Methods and patients: The MR examinations we re performed using a 1.5-Tesla unit with a circularly polarized head coil. All 20 patients (II females, nine males, aged from 12 to 80 years) with aco ustic neuromas underwent preoperative MRI with T2*-weighted 3D CISS (slice thickness, 0.7 mm; acquisition time, 8 min) and pre- and postcontrast T1-we ighted 3D MP-RAGE (slice thickness, 0.9 mm; acquisition time, 8 min) sequen ces. The detectability of acoustic neuromas was evaluated following the con sensus of three radiologists using a 3D work station (parameters: tumor pre sence, extent, nerve attribution). Results: All tumors were detected by bot h contrast-enhanced 3D MP-RAGE and 3D CISS and the diameters of the lesions were equally well measured. 3D CISS was the best sequence for the attribut ion of a lesion to a certain nerve. Labyrinthine involvement could be bette r detected using 3D CISS than contrast-enhanced 3D MP-RAGE. Conclusion: Hig h-resolution T2(*)-weighted MRI is a very sensitive method for tumor screen ing which can also detect even small meatal and labyrinthine neuromas. In t he case of abnormal findings (other pathology or variations, e.g. vascular loops); however, contrast-enhanced T1-weighted MRI is necessary in order to confirm the presence of a tumor with typical enhancement. (C) 1999 Elsevie r Science Ireland Ltd. All rights reserved.