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Moshfeghi M, Safi Y, Różyło-Kalinowska I, Gandomi S. Does the size of an object containing dental implant affect the expression of artifacts in cone beam computed tomography imaging? Head Face Med 2022; 18:20. [PMID: 35765076 PMCID: PMC9241278 DOI: 10.1186/s13005-022-00326-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 06/13/2022] [Indexed: 11/29/2022] Open
Abstract
Background Artifacts fault image quality but handling several factors can affect it. This study was conducted to investigate the effect of object size on artifacts in cone-beam computed tomography systems. Methods Five phantoms, each containing a titanium implant in a sheep bone block, were fabricated of various sizes ranging from XS to XL: The M phantom was the same size as the device’s field of view (FOV). The L and XL phantoms were 20 and 40% larger than the FOV while the S and XS phantoms were 20 and 40% smaller than FOV, respectively. Ballistic gelatin was used to fill the phantoms. Phantoms were scanned by NewTom VGI and HDXWill Q-FACE. The mean and standard deviation (SD) of gray values in each 120 ROI was obtained by OnDemand software. The contrast to noise ratio (CNR) was also calculated. Results The gray value in S and M phantoms were more homogenous. The lowest SD value (10.20) was found in S phantom. The highest value for SD (125.16) was observed in XL phantom. The lowest (4.47) and highest (9.92) CNR were obtained in XL and S phantoms, respectively. HDXWill Q-FACE recorded a higher SD and a lower CNR than NewTom VGI (P < 0.05). Conclusion Object dimensions of the FOV size or up to 20% smaller provided better image quality. Since the dimensions of soft tissue in most patients are larger than the selective FOV, it is recommended that in CBCT artifacts studies, an object with dimensions closer to the patient’s dimensions be used to better relate the results with the clinical condition, because the sample dimensions affect the amount of artifacts.
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Affiliation(s)
- Mahkameh Moshfeghi
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Yaser Safi
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ingrid Różyło-Kalinowska
- Department of Dental and Maxillofacial Radiodiagnostics, Medical University of Lublin, Lublin, Poland
| | - Shiva Gandomi
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
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Ito M, Hayashi Y, Matsumoto K, Arai Y, Honda K. Evaluation of cone-beam computed tomography over a small field of view in a water bath based on the modulation transfer function with repeating-edge oversampling. J Oral Sci 2020; 63:87-91. [PMID: 33311013 DOI: 10.2334/josnusd.20-0479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
PURPOSE The spatial resolution of cone-beam computed tomography (CBCT) in small fields of view (FOVs) is important for clinical applications. However, it is difficult to measure spatial resolution reliably due to error factors such as noise. The aim of this study was to obtain a modulation transfer function (MTF) more accurately. METHODS A CBCT apparatus was used with small FOV. An aluminum pipe slightly tilted at an inclination ratio of 77/3 (25.7) was used as the measurement phantom. The MTF was calculated from the edge image of the phantom. The actual oversampling ratio was determined by regression analysis. The experiment was repeated 16 times and the edge-spread function (ESF) was approximated by the least-square method. Furthermore, a low-pass filter (LPF) was applied to eliminate the component at frequencies above the Nyquist frequency. Finally, the MTF was calculated from the pre-processed ESF. RESULTS Results showed that pre-processing reduced the noise of the ESF. The MTFs at frequencies of 1.0 and 2.0 LP/mm were 0.59 and 0.18, respectively, in air and 0.52 and 0.16, respectively, in water. CONCLUSION The repeating-edge oversampling method combined with ESF pre-processing improved the accuracy of the MTF under clinically relevant conditions with a phantom.
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Affiliation(s)
- Motohiro Ito
- Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry
| | - Yusuke Hayashi
- Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry
| | - Kunihito Matsumoto
- Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry.,Division of Advanced Dental Treatment, Dental Research Center, Nihon University School of Dentistry
| | - Yoshinori Arai
- Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry.,Division of Advanced Dental Treatment, Dental Research Center, Nihon University School of Dentistry
| | - Kazuya Honda
- Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry.,Division of Advanced Dental Treatment, Dental Research Center, Nihon University School of Dentistry
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Candemil AP, Salmon B, Freitas DQ, Haiter-Neto F, Oliveira ML. Distribution of metal artifacts arising from the exomass in small field-of-view cone beam computed tomography scans. Oral Surg Oral Med Oral Pathol Oral Radiol 2020; 130:116-125. [PMID: 32057753 DOI: 10.1016/j.oooo.2020.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 12/11/2019] [Accepted: 01/10/2020] [Indexed: 12/19/2022]
Abstract
OBJECTIVES To evaluate the distribution of metal artifacts from the exomass in small field-of-view (FOV) cone beam computed tomography (CBCT) scans. STUDY DESIGN An image phantom was scanned by using 3 CBCT units. Metal objects were positioned in the exomass, and additional CBCT scans were obtained. Mean gray values were obtained from 16 homogeneous areas and the standard deviation was calculated to quantify gray level inhomogeneity according to distinct zones of the FOV: total area and outer, inner, right, left, and mid-zones. The discrepancy between each zone and the total area was calculated to compare different CBCT units. Mean gray, gray level inhomogeneity, and discrepancy values were separately assessed by using analysis of variance (ANOVA) and Tukey's test (α = 0.05). RESULTS Overall, the mean gray values were significantly lower in the inner zone, and the gray level inhomogeneity values were significantly higher in the inner and mid-zones irrespective of the presence of metal objects in the exomass. The 3 CBCT units presented significantly different discrepancy values in most conditions. CONCLUSIONS The distribution of metal artifacts from the exomass follows the inherent gray value dispersion of CBCT images, with greater inhomogeneity in the inner zone of the FOV. This is exacerbated when metal objects are in the exomass.
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Affiliation(s)
- Amanda P Candemil
- Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba (São Paulo), Brazil.
| | - Benjamin Salmon
- Université de Paris, Orofacial Pathologies, Imaging and Biotherapies EA2496 Lab, Montrouge, France; Dental Medicine Department, AP-HP, Bretonneau Hospital, Paris, France
| | - Deborah Queiroz Freitas
- Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba (São Paulo), Brazil
| | - Francisco Haiter-Neto
- Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba (São Paulo), Brazil
| | - Matheus Lima Oliveira
- Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba (São Paulo), Brazil
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Bayrak S, Kursun Cakmak ES, Kamalak H. Contrast-to-noise ratios of different dental restorative materials: an in-vitro cone beam computed tomography study. Eur Oral Res 2020; 54:36-41. [PMID: 32518909 PMCID: PMC7252535 DOI: 10.26650/eor.20200079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Purpose In radiological views, strong beam hardening and streaking artifacts occur due to high-density structures and polyenergetic X-ray beams, and these lead to misdiagnosis. This study was performed in vitro to compare the contrast-to-noise ratio (CNR) of commonly used dental restorative materials by using Cone Beam Computed Tomography (CBCT) images with and without artifact reduction (AR) mode. Materials and methods A total of 108 molar teeth were restored with nine different groups of restorative materials, with each group containing 12 teeth. Teeth were placed in a dry human mandible and scanned, one by one, via Planmeca 3D ProMax (Planmeca, Helsinki, Finland) with and without AR mode. Images were analyzed using ImageJ software (National Institutes of Health, Bethesda, MD) to calculate the CNR. Results CNR was calculated to be the highest in compomer (Glassiosite) images without AR mode (mean: 3.36) and with AR mode (mean: 3.61). CNR was calculated to be the lowest in amalgam (Tytin) images without AR mode (mean: 0.21) and with AR mode (mean: 0.23). A significant difference was found between materials in terms of CNR measurements (p ≤ 0.05). CNR measurements were increased after the AR mode application (p ≤ 0.05). Conclusion AR mode was effective in reducing artifacts arising from dental materials on CBCT images, so it is necessary to use AR mode for correct diagnoses.
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Affiliation(s)
- Seval Bayrak
- Abant İzzet Baysal University, Dentistry Faculty,Dentomaxillofacial Radiology Department, Bolu,Turkey
| | | | - Hakan Kamalak
- Kahramanmaras Sütcü İmam University, Dentistry Faculty, Department of Restorative Dentistry, Kahramanmaras,Turkey
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Queiroz PM, Santaella GM, da Paz TDJ, Freitas DQ. Evaluation of a metal artefact reduction tool on different positions of a metal object in the FOV. Dentomaxillofac Radiol 2017; 46:20160366. [PMID: 27910700 DOI: 10.1259/dmfr.20160366] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To evaluate the action of a metal artefact reduction (MAR) tool when artefact-generator metal object is at different positions in the field of view (FOV). METHODS A cylindrical utility wax phantom, with a metal alloy sample inside, was made. The phantom was positioned centrally and peripherally in the FOV for image acquisition, with and without the MAR tool activation. The standard deviation values (image noise levels) from areas around the metal sample and the control area were obtained. The numbers were compared by Student's t-test (α = 0.05). RESULTS When the tool was activated, a significant difference of image noise was observed for central and peripheral positioning, for both control area (p = 0.0012) and metal area (p = 0.03), and a smaller level of noise was observed for images with phantoms in central positioning. A decrease in image noise with the tool activated was found only in phantoms with the metal object positioned centrally in the FOV. CONCLUSIONS For the MAR tool to be effective, the artefact-generator object needs to be in the central region of the FOV.
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Affiliation(s)
- Polyane M Queiroz
- Department of Oral Diagnosis, Area of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil
| | - Gustavo M Santaella
- Department of Oral Diagnosis, Area of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil
| | - Thais D J da Paz
- Department of Oral Diagnosis, Area of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil
| | - Deborah Q Freitas
- Department of Oral Diagnosis, Area of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil
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de Oliveira MVL, Wenzel A, Campos PSF, Spin-Neto R. Quality assurance phantoms for cone beam computed tomography: a systematic literature review. Dentomaxillofac Radiol 2017; 46:20160329. [PMID: 28045345 DOI: 10.1259/dmfr.20160329] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
OBJECTIVES To undertake a systematic review on quality assurance (QA) phantoms for CBCT imaging, including studies on the development and application of phantoms. METHODS The MEDLINE (PubMed) bibliographic database was searched until May 2016 for studies evaluating the development and use of phantoms in CBCT image QA. The search strategy was restricted to English language publications using the following combined terms: (Cone Beam CT) OR (Cone Beam Computed Tomography) OR (Cone-Beam Computed Tomography) OR (CBCT) AND (quality OR phantom). It was assessed which of the six image quality parameters stated by the European Commission could be evaluated with each phantom and which of them actually were. RESULTS The search strategy yielded 37 studies, which had developed and used (25 studies) or only used (12 studies) a phantom in CBCT image QA. According to the literature, in 7 phantoms, it is possible to evaluate 4 or more image quality parameters while in 11 phantoms, merely 1 parameter can be evaluated. Only two phantoms permit the evaluation of the six image quality parameters stated by the European Commission. The parameters, which can most often be evaluated using a phantom, are image density values, spatial resolution and geometric accuracy. The SEDENTEXCT phantom was used most frequently. In two studies, all quality parameters suggested by the European Commission were evaluated. CONCLUSIONS QA phantoms rarely allow all image quality parameters stated by the European Commission to be evaluated. Furthermore, alternative phantoms, which allow all image quality parameters to be evaluated in a single exposure, even for a small field of view, should be developed.
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Affiliation(s)
- Marcus V L de Oliveira
- 1 Department of Health Technology and Biology, Federal Institute of Bahia, Salvador, Brazil.,2 Institute of Health Sciences, Department of Interactive, Processes of Organs and Systems, Federal University of Bahia, Salvador, Brazil
| | - Ann Wenzel
- 3 Oral Radiology, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark
| | - Paulo S F Campos
- 2 Institute of Health Sciences, Department of Interactive, Processes of Organs and Systems, Federal University of Bahia, Salvador, Brazil
| | - Rubens Spin-Neto
- 3 Oral Radiology, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark
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