Detection of the mandibular canal via shaded surface display and multiplanar reconstruction of CT data

The purpose of this study was to evaluate the sensitivity of conventional t wo-dimensional (2D) multisection images (multiplanar rendering, MPR) and re gistered three-dimensional (3D) shaded surface images (shaded surface displ ay, SSD) of standard axial computed tomography (CT) data for detecting the mandibular canal (MC) in the lower jaw of 136 patients. The patients, who h ad different indications for mandibular CT, were examined using standard ax ial CT scanning. Two post-processing programs were used for 3D visualizatio n of the data sets. The cross-sectional rendered images and the shaded surf ace 3D images were graded for detection of the MC, the presence of artefact s, overall quality and clinical relevance. A 3D display of the MC was achie ved using the MPR technique in 100% with high image quality. The surface re ndered display depicted the MC in 80%. Artefacts markedly degraded the 3D d isplays obtained using the surface rendering technique; thus, SSD is an ina ppropriate technique for imaging the entire MC without manual segmentation. MPR-CT improves the sensitivity of CT imaging in the detection of the MC w ith very little time needed for post-processing compared with the SSD metho d. This post-processing modality should, therefore, be considered for seria l studies of patients undergoing dental CT. The sensitivity of the MPR meth od is even superior to the standard axial CT slices.