Inner ear anomaly of three-dimensional computed tomography: computed tomographic attenuation and image changes.

With regard to image diagnosis of inner ear anomalies, three-dimensional computed tomography (3D-CT) is useful in obtaining very realistic images that are unmatched by 2D-CT. Unlike the step scanning in the existing 2D-CT, in helical 3D-CT, scanning is performed in a spiral motion by continuously rotating the scanner and moving the table along the body axis at a constant speed. As a result, data obtained by this CT are continuous and very smooth curves can be obtained. Among the data, the CT attenuation determines the quality of the final 3D images. In the present paper, the usefulness of 3D-CT was investigated in a case with Mondini-type inner ear malformation.