Accuracy of single-sequence MRI for investigation of the fluid-filled spaces in the inner ear and cerebellopontine angle

We prospectively studied 163 patients referred for MRI of the temporal bone . A presumed diagnosis was made using only one of three sequences: a single thick (12 mm) slice fast T2-sequence, 3D fourier transform constructive in terference in steady state (3DFT-CISS) sequence and a gadolinium-enhanced T 1-weighted sequence. The visibility of the cochlea, vestibule and superior, lateral and posterior semicircular canals of normal temporal bones was ass essed on the T2-weighted images: they were almost always visible (98-100%), with exception of the superior semicircular canal, seen in only 35% of cas es. The images were interpreted as abnormal in 34 patients (21%). Using nor mal in 34 patients (21%). Using only the fast T2-weighted, 3DFT-CISS and ga dolinium-enhanced T1-weighted sequences a presumed false positive diagnosis was made in 5, 1 and 0 cases and a false negative diagnosis in 2, 2 and 4 cases respectively. The overall reliability of the thick-section fast T2-we ighted images is limited. This study suggests that a combination of gadolin ium-enhanced T1-weighted and 3DFT-CISS images can be considered the gold st andard for temporal bone MRI and neither sequence performed separately is a s accurate as both together.