Visualization of inner ear dysplasias in patients with sensorineural hearing loss - High-resolution MR imaging and volume-rendered reconstructions

Purpose: We evaluated a data acquisition and post-processing protocol for i nner ear (IE) assessment by MR imaging in patients. suffering from various labyrinth malformations. Material and Methods: MR IE studies of 158 consecutive patients (316 IEs) s uffering from sensorineural hearing loss without evidence of an acoustic ne urinoma were reviewed for pathologies of the IE and internal acoustic meatu s. High-resolution MR data of all abnormal IE studies (n=45) were post-proc essed to previously standardized 3D volume rendered (VR) reconstructions. Results: In 9 patients (5.7%) the following IE dysplasias were detected: ma lformation of the cochlea (6 IEs), vestibulum (4 IEs). semicircular canals (12 IEs) and vestibular aqueduct/endolymphatic sac (10 IEs). One patient sh owed evidence of an aplasia of the vestibulocochlear nerve. In 4 patients m ultiple IE dysplasias were encountered. Comprehensive 3D visualization of a ll labyrinthine dysplasias was achieved by the use of two VR reconstruction s. The overall time for bilateral IE assessment amounted to 30-35 min. Conclusion: The imaging protocol allows for rapid and comprehensive visuali zation of various IE dysplasias, based on a limited number of VR reconstruc tions.