Teaching tool for advanced visualization of temporal bone structures by fusion of μCT and CT scan images

Main goal Improve the understanding of human temporal bone computed tomography (CT) scans based on semi-automatically segmented microcomputed tomography (µCT). Introduction The three-dimensional ear anatomy is complex and challenging to interpret in CT scans because small structures are partially visible. Histological slices provide complementary high-resolution information, but may lead to geometrical distortions of the anatomy during preparation. Conversely, µCT preserves the shape. 3D images acquisition and segmentation o Five freshly cadaveric pairs of temporal bones o Acquisition of CT (General Electric; Light Speed VTC 64) ) and a µCT (General Electric; eXplore speCZT) images o Seed-based segmentation of every reliable anatomical structures on CT or µCT Rigid registration of µCT and CT o First, rough point-based registration using anatomical landmarks o Second, automatic rigid registration using a block matching framework Results High resolution structures are fused and visualized on corresponding CT images. This experience significantly improves the visual recognition and spatial understanding of partially visible structures (e.g. tympanic scala, facial nerve and chorda tympani) in CT images. Conclusion Geometrically accurate temporal bone reconstructions provide an advanced teaching tool for medical students and cochlear implant surgeons. The understanding of spatial relationship between anatomical structures as well as the virtual exploration of surgical approaches is greatly facilitated.