ANATOMY OF THE TEMPORAL BONE - DETAILED 3-DIMENSIONAL DISPLAY BASED ON IMAGE DATA FROM HIGH-RESOLUTION HELICAL CT - A PRELIMINARY-REPORT

Our purpose was to demonstrate the application of helical computed tom ography (CT) for computer graphics of the normal temporal bone with sp ecial regard to inner ear structures. Three-dimensional reconstruction of temporal bones was performed from helical CT data on 41 patients w ith various otologic diseases. Image postprocessing was carried out on an independent work station. In contrast to former surface-rendered t hree-dimensional visualizations of the temporal bone, a volumetric-ren dering algorithm was used. This technique allows automated segmentatio n, thresholding, and simultaneous visualization of different planes (c ube-cutting) in near-real time. We were able to demonstrate the three- di mensional display of the labyrinth during clinical routine. Anatomi c derails (internal auditory canal, cochlea, vestibulum, semicircular canals, distal part of the vestibular aqueduct, complete ossicular cha in, fallopian canal, internal carotid canal) were comprehensively demo nstrated by interactive segmentation or thresholding. Difficulties wer e found in three-dimensional delineation of the complete vestibular an d cochlear aqueduct, as well as the modiolus. Initial experience with an advanced helical CT-based three-dimensional display showed excellen t images of temporal bone anatomy. Validation studies with correlative histologic sections and surgical dissections remain to be done.