Evaluation of a cone beam CT artefact reduction algorithm

Abstract

Improved quality of images and regaining of the control gray values of a phantom were achieved when the MAR algorithm was used in the presence of a metallic bead.

Influence of the artefact reduction algorithm of Picasso Trio CBCT system on the diagnosis of vertical root fractures in teeth with metal posts

“…21,22 By analysing mean greyscale values in a similar CBCT equipment, both with and without the use of AR, Bechara et al 22 showed that this value was significantly lower with the use of such tool, corroborating the results of our study. On the other hand, Bechara et al 21 observed a significant increase in mean greyscale values using the AR in the presence of metal, while values were reduced in the absence of metal. However, both reports used phantoms and assessed different areas, while our study simulated a clinical condition.…”

“…21,29 However, the results of this study showed a decrease of this ratio when AR was used, while Bechara's group 21,22 have reported that the CNR is increased with AR use. In addition, one must consider that these studies were conducted in phantoms and, despite satisfactory standardization, evaluate variables that may not be present in clinical situations.…”

“…For fracture induction, 20 roots were randomly selected and placed in an acrylic block, which was positioned on a universal testing machine (model 4411; Instron ® Corporation, Canton, MA), and fractures were induced by applying a 500 N load at a speed of 1 mm min 21 . The process of fracture induction was confirmed under visual inspection and transillumination with an light emitting diode photopolymerization unit (UltraLume 5; Ultradent Products Inc., South Jordan, UT).…”

“…However, few studies have evaluated this tool, and the results are inconclusive as to its influence on the final image quality. [21][22][23] When evaluated for root fracture diagnosis in teeth filled with gutta-percha, the use of an AR led to decreased diagnostic sensitivity and specificity. 4 Additionally, no differences were observed in the detection of simulated periodontal and peri-implant vestibular defects with or without the use of an AR.…”

Contrast-to-noise ratio difference in small field of view cone beam computed tomography machines

“…The CBCT units used were the 3D Accuitomo (Field of view (FOV) 3 × 4 cm) and 3D Accuitomo FPD (FOVs 4× 4 cm and 6 × 6 cm) both manufactured by J Morita, Kyoto, Japan; a rotation of 180° compared to a 360° which takes twice the time to be acquired, gave good subjective image quality, hence a substantial dose reduction can be achieved without loss of diagnostic information. In addition, Bechara et al concluded that metal artifacts cause a decrease in CNR (22,23). The increase in CNR found in this study when increasing the basis images in the Accuitomo machine may be used to counteract the effects of metal artifacts.…”