Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013;42(2):32310645.
doi: 10.1259/dmfr/32310645. Epub 2012 Jul 27.

Cone beam CT image artefacts related to head motion simulated by a robot skull: visual characteristics and impact on image quality

R Spin-Neto  1 , J Mudrak, L H Matzen, J Christensen, E Gotfredsen, A Wenzel
Affiliations

Cone beam CT image artefacts related to head motion simulated by a robot skull: visual characteristics and impact on image quality

R Spin-Neto et al. Dentomaxillofac Radiol. 2013.

Abstract

Objectives: The aim of this study was to assess artefacts and their impact on cone beam CT (CBCT) image quality (IQ) after head motion simulated by a robot skull.

Methods: A fully dentate human skull incorporated into a robot simulated pre-determined patient movements. Ten head motion patterns were selected based on the movement of the C-arm of the CBCT units (no motion as reference). Three CBCT units were used [a three-dimensional eXam (K) (KaVo Dental GmbH, Biberach, Germany), a Promax 3D MAX (P) (Planmeca Oy, Helsinki, Finland) and a Scanora(®) 3D (S) (Soredex Oy, Tuusula, Finland)]. Axial images were qualitatively assessed at three levels: mental foramen (MF), infraorbital foramen and supraorbital foramen, and artefacts characterized as stripe-like, double contours, unsharpness or ring-like. A 100 mm visual analogue scale (VAS) was used to quantitatively assess IQ. Cross-sectional images of the lower third molar and MF bilaterally were also evaluated by VAS. Four blinded examiners assessed the images.

Results: For all units and motion patterns, stripe-like artefacts were the most common. The four observers agreed on the presence of at least one artefact type in 90% of the images. Axial images showed lower overall IQ after motion (VAS = 72.4 ± 24.0 mm) than reference images (VAS = 97.3 ± 2.6 mm). The most severe artefacts were seen at the MF level. For cross-sectional images, IQ was lowest after tremor. The mean IQ range was 74-89 and 57-90 for isolated (tilting, rotation and nodding) and combined (nodding + tilting and rotation + tilting) movements, respectively. IQ for MF was lower than for third molar for any movement except tremor.

Conclusions: Head motion of any type resulted in artefacts in CBCT images. The impact on IQ depended on the region and level in the skull.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Sketch of skull illustrating the planes of movement and the foramina with radio-opaque markers: supraorbital foramen (a), infraorbital foramen (b) and mental foramen (c)
Figure 2
Figure 2
Examples of axial images, generated using a Scanora 3D (Soredex Oy, Tuusula, Finland). First row (a,b,c) shows reference images without motion artefacts. Second row (d,e,f) shows images with tremor artefacts. (a,d) Mental foramen; (b,e) infraorbital foramen; (c,f) supraorbital foramen
Figure 3
Figure 3
Examples of cross-sectional images of the lower third molar region, generated using three-dimensional eXam (KaVo Dental GmbH, Biberach, Germany). (a) Reference image; (b) image with motion (tremor) artefacts
Figure 4
Figure 4
Examples of cross-sectional images of the mental foramen region, generated using ProMax 3D MAX (Planmeca Oy, Helsinki, Finland). (a) Reference image; (b) image with motion (tremor) artefacts
See this image and copyright information in PMC

References

    1. Miracle AC, Mukherji SK. Conebeam CT of the head and neck, part 1: physical principles. Am J Neuroradiol 2009; 30: 1088–1095 - PMC - PubMed
    1. Miracle AC, Mukherji SK. Conebeam CT of the head and neck, part 2: clinical applications. Am J Neuroradiol 2009; 30: 1285–1292 - PMC - PubMed
    1. Hanzelka T, Foltan R, Horka E, Sedy J. Reduction of the negative influence of patient motion on quality of CBCT scan. Med Hypotheses 2010; 75: 610–612 - PubMed
    1. Schulze R, Heil U, Grob D, Bruellmann DD, Dranischnikow E, Schwanecke U, et al. Artefacts in CBCT: a review. Dentomaxillofac Radiol 2011; 40: 265–273 - PMC - PubMed
    1. Draenert FG, Coppenrath E, Herzog P, Muller S, Mueller-Lisse UG. Beam hardening artefacts occur in dental implant scans with the NewTom cone beam CT but not with the dental 4-row multidetector CT. Dentomaxillofac Radiol 2007; 36: 198–203 - PubMed