MRI OF INNER-EAR AND FACIAL-NERVE PATHOLOGY USING 3D MP-RAGE AND 3D CISS SEQUENCES

The aim of this study was to evaluate 3D CISS, unenhanced 3D MP-RAGE a nd contrast enhanced 3D MP-RAGE for the diagnosis of neoplastic, vascu lar and inflammatory lesions of the cerebellopontine angle, the inner auditory canal, the labyrinth and the facial nerve. 42 MR examinations were performed on a total of 38 patients (25 males, 13 females; aged 1-77 years, mean age 43 +/- 20 years) using a 1.5 T MR unit. A T-2() weighted 3D CISS sequence (TR 14.65 ms, TE 21 ms, flip angle 65 degree s, voxel size 0.7 x 0.7 x 0.3 mm(3)) and a T-1 weighted 3D MP-RAGE seq uence (TR 12.5 ms. TE 5 ms, TI 300 ms, flip angle 15 degrees, voxel si ze 1.0 x 0.9 x 0.9 mm(3)) with and without contrast medium (gadolinium -DTPA, 0.1 mmol kg(-1) body weight) were used. Results of contrast enh anced 3D MP-RAGE-pathological enhancement was found in the following l esions: schwannomas of the cerebellopontine angle (CPA) and the intern al auditory canal (IAC), 4; schwannomas of the IAC, ? and labyrinthine tumours, 3; posterior fossa lymphoma, I; meatal meningioma, 1; acute labyrinthitis, 15 and neuritis of the seventh cranial nerve, 10. Resul ts of 3D CISS-filling defects were found with the following lesions: s chwannomas of the CPA, the IAC or labyrinth, 14; lymphoma, 1; meningio ma, 1; labyrinthine fibrosis, 13 and scar in the IAC, 4. These results suggest that unenhanced and contrast enhanced 3D MP-RAGE: and 3D CESS are complementary MR imaging modalities. T-1 weighted 3D MP-RAGE is p referred to T-1 weighted 2D (turbo) spin echo sequences because of the multiplanar reconstruction possibilities of 3D sequences, which are v ery useful in the case of the inner ear and facial nerve.