Effects of image artifacts on gray-value density in limited-volume cone-beam computerized tomography

Objective. An in vitro study was designed to investigate the influence of projection data discontinuity-related artifacts in limited-volume cone-beam computerized tomography (CBCT) imaging of the jaws. Study design. Test objects were positioned in 4 patterns in a water-filled phantom as follows: bimandible and vertebrae, bimandible, left mandible and vertebrae, and left mandible. The CT imaging of the left molar region was performed using image intensifier (II)- and flat panel detector (FPD)-based CBCT scanners. The CT value of the mandible and the adjacent soft tissue region were analyzed for density by means of an 8-bit grayscale. Results. The effects of artifacts were scored as the difference in relative density between the lingual and buccal soft tissue. The intensity of artifacts increased when more objects were presented outside the area being imaged. Fewer artifacts were noted in images produced by the particular FPD CBCT used in this investigation. Conclusion. The CBCT system using an FPD resulted in fewer artifacts than the CBCT system using an II in this particular study.