MRI of inner ear and facial nerve pathology using 3D MP-RAGE and 3D CISS sequences

Abstract

The aim of this study was to evaluate 3D CISS, unenhanced 3D MP-RAGE and contrast enhanced 3D MP-RAGE for the diagnosis of neoplastic, vascular 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 T2* weighted 3D CISS sequence (TR 14.65 ms, TE 21 ms, flip angle 65 degrees, voxel size 0.7 x 0.7 x 0.7 mm3) and a T1 weighted 3D MP-RAGE sequence (TR 12.5 ms, TE 5 ms, T1 300 ms, flip angle 15 degrees, voxel size 1.0 x 0.9 x 0.9 mm3) with and without contrast medium (gadolinium-DTPA, 0.1 mmol kg-1 body weight) were used. Results of contrast enhanced 3D MP-RAGE-pathological enhancement was found in the following lesions: schwannomas of the cerebellopontine angle (CPA) and the internal auditory canal (IAC), 4; schwannomas of the IAC, 7 and labyrinthine tumours, 3; posterior fossa lymphoma, 1; meatal meningioma, 1; acute labyrinthitis, 15 and neuritis of the seventh cranial nerve, 10. Results of 3D CISS-filling defects were found with the following lesions: schwannomas of the CPA, the IAC or labyrinth, 14; lymphoma, 1; meningioma, 1; labyrinthine fibrosis, 13 and scar in the IAC, 4. These results suggest that unenhanced and contrast enhanced 3D MP-RAGE and 3D CISS are complementary MR imaging modalities. T1 weighted 3D MP-RAGE is preferred to T1 weighted 2D (turbo) spin echo sequences because of the multiplanar reconstruction possibilities of 3D sequences, which are very useful in the case of the inner ear and facial nerve.