Dental CT metal artefact reduction based on sequential substitution

Tohnak, S., Mehnert, A. J. H., Mahoney, M. and Crozier, S. (2011) Dental CT metal artefact reduction based on sequential substitution. Dentomaxillofacial Radiology, 40 3: 184-190. doi:10.1259/dmfr/25260548


Author Tohnak, S.
Mehnert, A. J. H.
Mahoney, M.
Crozier, S.
Title Dental CT metal artefact reduction based on sequential substitution
Journal name Dentomaxillofacial Radiology   Check publisher's open access policy
ISSN 0250-832X
1476-542X
Publication date 2011
Year available 2011
Sub-type Article (original research)
DOI 10.1259/dmfr/25260548
Volume 40
Issue 3
Start page 184
End page 190
Total pages 7
Place of publication London, United Kingdom
Publisher British Institute of Radiology
Collection year 2012
Language eng
Subject 2741 Radiology Nuclear Medicine and imaging
2733 Otorhinolaryngology
3500 Dentistry
Abstract Objective: Metal artefacts can seriously degrade the visual quality and interpretability of dental CT images. Existing image processing algorithms for metal artefact reduction (MAR) are either too computationally expensive to be used in clinical scanners or effective only in correcting mild artefacts. The aim of the present study was to investigate whether it is possible to improve the efficacy of the computationally efficient projection-correction approach to MAR by exploiting the spatial dependency or autocorrelation between adjacent CT slices. Methods: A new projection-correction algorithm [MAR by sequential substitution (MARSS)] was developed based on the idea that the corrupted portions of the projection data can be substituted with the corresponding portions from an unaffected adjacent slice. The performance of MARSS was evaluated relative to the projection-correction method of Watzke and Kalendar using a two-alternative forced choice (2AFC) visual trial involving 20 observers and 20 clinical CT data sets.16 Results: The Cochran Q test revealed no significant difference in the responses across all observers. The data were then pooled and analysed using a one-tailed exact binomial test. This revealed that the proportion of responses in favour of MARSS was significant (P < 2.2610 -16). A second Cochran Q test revealed no significant difference in the responses across all images. Conclusions: It is possible to improve the efficacy of projection correction by exploiting spatial autocorrelation. The 2AFC results suggest that the proposed MARSS algorithm outperforms competing computationally efficient algorithms in terms of reducing metal artefacts whilst at the same time preserving revealing anatomic detail.
Keyword Artefacts
Computed tomography
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Information Technology and Electrical Engineering Publications
 
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