Diagnosis of Ossicular Deformities and Inner Ear Anomalies by High Resolution CT Scanning of the Temporal Bone

Abstract

A comparative study was undertaken to determine the optimum slice thickness and slice gaps that can define the fine contour and continuity of the ossicles and the inner ear. Horizontal tomography was proved to be contributory enough to obtain the whole ossicular chains and the whole labyrinthine capsule. Comparison of 1.5mm slice thickness /1.5 mm slice gaps,1.0 mm slice thickness /1.0 mm slice gaps and 1.5 mm slice thickness /1.0 mm slice gaps revealed that the last condition was optimal for demonstrating the ossicular chains, the first for the inner ear. A significant relationship was found between CT findings and surgical findings of ossicular chains in chronic otitis media and cholesteatoma. Radiological classification of the inner ear malformation, which was obtained by this method, were agenesis of the whole labyrinthine capsule, agenesis of the cochlea, slight protrusion of the cochlear growth, poor cochlear turning, agenesis of all the semicircular canals, anterior semicircular canals (s.c) without posterior and lateral s.c., anterior s.c. without hypoplasia of posterior s.c. and aplasia of lateral s.c., and smallness of the vestibule.