Figure 2.

The image with weighted filtered back-projection (WFBP) (a, g) showed some minor artefacts in the region of the tongue and spinal canal. However, many new streak artefacts (arrows) appeared on the same image with the linear interpolation metal artefact reduction (MARli) algorithm (b) around the mandible and cervical spine. Compared with the MARli algorithm, the normalized metal artefact reduction (NMAR) algorithm (c) generated fewer new streak artefacts. (d–f) The corresponding sinograms of the WFBP, MARli and NMAR algorithms. The sinograms were created by forward-projecting from the final images after the metal artefact reduction algorithms were applied. Metal mask contours for MARli (h) and NMAR (i) are indicated on corresponding images with red circles