Spiral CT of the temporal bone: value of image reconstruction at submillimetric table increments

Axial spiral CT of the temporal bones with a nominal slice thickness of 1 mm and 180 degrees linear interpolation was performed in 13 patients. In 18 temporal bones, the spiral data set was used to reconstruct overlapping axial images with a table increment of 0.1 mm. These images gave additional information in four cases: in two by examining the heavily overlapping axial images themselves, and in two by obtaining supplementary information from secondary image reconstructions. In two cases less information was obtained than by using the conventional incremental images. This study shows that reconstructing overlapping slices can be useful, even if the temporal bone is scanned at 1 mm nominal slice thickness.