Figure 3.

The image with weighted filtered back-projection (WFBP) (a, g) showed severe streak artefacts from dental fillings in the left mandible, which was evaluated as a score of 3 (arrow). Artefacts were significantly reduced with both linear interpolation metal artefact reduction (MARli) and normalized metal artefact reduction (NMAR) algorithms, with each receiving a score of 2 (arrows). The NMAR algorithm was superior to the MARli algorithm in removing the streak artefacts, especially in the region of the tongue and bilateral masseter muscles. (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