Axial HRCT, two-dimensional and maximum intensity projection reconstructions in temporal bone lesions.

Axial and coronal high resolution computer tomography (HRCT) of the temporal bone is an important imaging technique to evaluate hearing loss. However the acquisition of the coronal imaging proves uncomfortable to the patient and is not always technically possible in old and ill patients. Clinical diagnoses of chronic otitis media, mastoiditis, cholesteatoma and cochlear otosclerosis in 10 patients were studied on a third generation CT scanner. Axial 1 mm HRCT slices were acquired and the images were transferred to an Advantage Windows workstation where two-dimensional (2D) multiplanar and sagittal maximum intensity projection (MIP) reformations were performed. Our aim was to study the ability of this technique to identify several small structures of the temporal bone in various diseases. In all cases the finer structures of the temporal bone were identified in axial HRCT images. The tegmen tympani, atticus and the cochlea were best seen in the 2D coronal reconstructions. The aditus ad antrum, facial canal, vestibule and the semicircular canals were best seen on 2D sagittal reconstructions. The joints between the bony ossicles of the middle ear was best seen in the sagittal MIP reconstructions. Our results suggest that axial HRCT, 2D multiplanar and MIP reconstructions of the temporal bone produce images with sufficient diagnostic quality in patients with hearing loss.