Expression of beam hardening artifacts on horizontally stitched cone-beam computed tomography images

This study was performed to evaluate the expression of beam hardening artifacts generated by high atomic number materials in stitched cone-beam computed tomography (CBCT) images, compared to the traditional acquisition mode.

CBCT volumes were acquired using an acrylic resin phantom embedded with pairs of cylinders made from amalgam dental alloy, cobalt-chromium alloy, gutta-percha, titanium, and zirconium. These cylinders were placed within the overlapping zones of the stitching reconstruction area. For each material, 3 acquisitions were conducted: 1 utilizing the automatic stitching process with a FOV of 80×37 mm, and 2 with smaller FOVs of 50×37 mm. For the smaller FOVs, 1 scan targeted the anterior region, while the other focused on the left posterior region. Thus, 3 groups were formed: stitched FOV, anterior FOV, and posterior FOV. Artifact expression was assessed by calculating the means and standard deviations (SDs) of the gray values in 4 regions of interest located anteriorly, posteriorly, medially, and laterally to the cylinders. Analysis of variance was used to compare the data, with an alpha level of 5%.

The stitched FOV exhibited lower SD values than the posterior and anterior FOVs (P<0.05). Regarding the materials evaluated, amalgam, cobalt-chromium, and zirconium generally demonstrated higher SDs of the gray values than gutta-percha and titanium (P<0.05).

Horizontally stitched CBCT images demonstrated lower artifact expression compared to the traditional mode of acquisition.