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Vidor MM, Liedke GS, Fontana MP, da Silveira HLD, Arus NA, Lemos A, Vizzotto MB. Is cone beam computed tomography accurate for postoperative evaluation of implants? An in vitro study. Oral Surg Oral Med Oral Pathol Oral Radiol 2017; 124:500-505. [PMID: 28867464 DOI: 10.1016/j.oooo.2017.07.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 07/18/2017] [Accepted: 07/22/2017] [Indexed: 11/17/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate the accuracy of cone beam computed tomography (CBCT) for evaluation of the bone-implant interface in comparison with periapical radiography. STUDY DESIGN Titanium implants were inserted in 74 bovine rib blocks in intimate contact with bone walls and with a gap of 0.125 mm (simulating failure in the osseointegration process). Periapical radiographs were taken with conventional film, and CBCT scans were acquired with i-CAT (0.2 mm and 0.125 mm voxel) and Kodak (0.2 mm and 0.076 mm voxel) units. Three examiners evaluated the images using a 5-point scale. Diagnostic accuracy was analyzed through sensitivity, specificity, and the area under the receiver operating characteristic (ROC) curve (AUC) with 95% confidence intervals (CIs). Intra- and interexaminer agreements were analyzed through Kendall's concordance test. RESULTS Intra- and interexaminer agreements showed satisfactory results. The greatest accuracy was observed with conventional radiography (AUC = 0.963; CI 95% = 0.891-0.993). I-CAT 0.125-mm images showed good accuracy (AUC = 0.885; CI 95% = 0.790-0.947), with no significant difference compared with conventional radiography. Kodak images had high specificity and low sensitivity, presenting more false-negative results. CONCLUSIONS Conventional radiography showed the highest accuracy for assessment of the bone-implant interface. However, CBCT (i-CAT; 0.125-mm voxel), if available or if performed for preoperative assessment of another implant site, may provide similar accuracy.
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Affiliation(s)
- Michele Machado Vidor
- Oral Radiology, Department of Surgery and Orthopedics, School of Dentistry, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Gabriela Salatino Liedke
- Oral Radiology, Department of Stomatology, School of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Brazil.
| | - Mathias Pante Fontana
- Oral Radiology, Department of Surgery and Orthopedics, School of Dentistry, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Heraldo Luis Dias da Silveira
- Oral Radiology, Department of Surgery and Orthopedics, School of Dentistry, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Nadia Assein Arus
- Oral Radiology, Department of Surgery and Orthopedics, School of Dentistry, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | | | - Mariana Boessio Vizzotto
- Oral Radiology, Department of Surgery and Orthopedics, School of Dentistry, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
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Impact of cone-beam computed tomography scan mode on the diagnostic yield of chemically simulated external root resorption. Am J Orthod Dentofacial Orthop 2017; 151:1073-1082. [PMID: 28554453 DOI: 10.1016/j.ajodo.2016.10.041] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 10/01/2016] [Accepted: 10/01/2016] [Indexed: 11/21/2022]
Abstract
INTRODUCTION The aim of this in-vitro study was to evaluate the influence of cone-beam computed tomography scans on the diagnosis of chemically simulated external root resorption. METHODS One hundred extracted anterior teeth were selected. Subsurface demineralization was induced on a limited area of the apical third of the root of 49 teeth. Each tooth was placed in an empty socket of a partially edentulous dry mandible. Cone-beam computed tomography images were obtained according to 3 protocols: (1) half scan, 0.40-mm voxel size; (2) full scan, 0.40-mm voxel size; and (3) full scan, 0.125-mm voxel size. Three observers evaluated the images. Sensitivity, specificity, accuracy, and area under the curve were compared with the Cochran Q and Mann-Whitney U tests. RESULTS Protocol 3 had the highest sensitivity (81.63%), accuracy (80.67%), and area under the curve (0.807). There were statistically significant differences between protocol 3 and the other 2 protocols (P <0.001). The specificity of protocol 1 (84.97%) was greater than that of protocols 2 (69.93%) and 3 (79.74%); however, a statistically significant difference was found only between protocols 1 and 2 (P = 0.005). CONCLUSIONS A more dedicated, high-resolution scan should be acquired when one intends to investigate the early stage of external root resorption during orthodontic treatment. However, this does not imply that all orthodontic patients should be subjected to high-dose cone-beam computed tomography scans.
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Koivisto J, van Eijnatten M, Järnstedt J, Holli-Helenius K, Dastidar P, Wolff J. Impact of prone, supine and oblique patient positioning on CBCT image quality, contrast-to-noise ratio and figure of merit value in the maxillofacial region. Dentomaxillofac Radiol 2017; 46:20160418. [PMID: 28306334 DOI: 10.1259/dmfr.20160418] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To assess the impact of supine, prone and oblique patient imaging positions on the image quality, contrast-to-noise ratio (CNR) and figure of merit (FOM) value in the maxillofacial region using a CBCT scanner. Furthermore, the CBCT supine images were compared with supine multislice CT (MSCT) images. METHODS One fresh frozen cadaver head was scanned in prone, supine and oblique imaging positions using a mobile CBCT scanner. MSCT images of the head were acquired in a supine position. Two radiologists graded the CBCT and MSCT images at ten different anatomical sites according to their image quality using a six-point scale. The CNR and FOM values were calculated at two different anatomical sites on the CBCT and MSCT images. RESULTS The best image quality was achieved in the prone imaging position for sinus, mandible and maxilla, followed by the supine and oblique imaging positions. 12-mA prone images presented high delineation scores for all anatomical landmarks, except for the ear region (carotid canal), which presented adequate to poor delineation scores for all studied head positions and exposure parameters. The MSCT scanner offered similar image qualities to the 7.5-mA supine images acquired using the mobile CBCT scanner. The prone imaging position offered the best CNR and FOM values on the mobile CBCT scanner. CONCLUSIONS Head positioning has an impact on CBCT image quality. The best CBCT image quality can be achieved using the prone and supine imaging positions. The oblique imaging position offers inadequate image quality except in the sinus region.
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Affiliation(s)
- Juha Koivisto
- 1 Department of Oral and Maxillofacial Surgery/Oral Pathology and 3D Innovation Lab, VU University Medical Center, Amsterdam, Netherlands
| | - Maureen van Eijnatten
- 1 Department of Oral and Maxillofacial Surgery/Oral Pathology and 3D Innovation Lab, VU University Medical Center, Amsterdam, Netherlands
| | - Jorma Järnstedt
- 2 Medical Imaging Center, Department of Radiology, Tampere University Hospital, Tampere, Finland
| | - Kirsi Holli-Helenius
- 2 Medical Imaging Center, Department of Radiology, Tampere University Hospital, Tampere, Finland
| | - Prasun Dastidar
- 2 Medical Imaging Center, Department of Radiology, Tampere University Hospital, Tampere, Finland.,3 University of Tampere, Medical School, Tampere, Finland
| | - Jan Wolff
- 1 Department of Oral and Maxillofacial Surgery/Oral Pathology and 3D Innovation Lab, VU University Medical Center, Amsterdam, Netherlands
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204
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Trends in maxillofacial imaging. Clin Radiol 2017; 73:4-18. [PMID: 28341434 DOI: 10.1016/j.crad.2017.02.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 01/23/2017] [Accepted: 02/09/2017] [Indexed: 11/20/2022]
Abstract
Maxillofacial imaging encompasses radiology of the teeth and jaws, including the temporomandibular joints. Modalities used include intra-oral radiographs, panoramic tomography, cephalograms, cone-beam computed tomography, computed tomography, magnetic resonance imaging, ultrasound, and radionuclide imaging. Common indications for imaging are impacted and supernumerary teeth, dental implants, inflammatory dental disease, and fibro-osseous lesions, cysts, and masses of the jaws. Osteonecrosis of the jaws may follow radiotherapy or the use of bisphosphonates and other drugs. Imaging of the temporomandibular joints and the potential role of imaging in obstructive sleep apnoea are also discussed.
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Influence of acquisition parameters on the evaluation of mandibular third molars through cone beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol 2017; 124:183-190. [PMID: 28483471 DOI: 10.1016/j.oooo.2017.03.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/02/2017] [Accepted: 03/04/2017] [Indexed: 11/21/2022]
Abstract
OBJECTIVES The aim of the study was to assess the influence of cone beam computed tomography (CBCT) acquisition parameters on the evaluation of mandibular third molars and their relationship to the mandibular canal. STUDY DESIGN Eight dry human mandibles with 13 mandibular third molars were scanned with one CBCT unit. Voxel size (0.2 and 0.3 mm), field of view (FOV) size (12 × 8.5 cm and 5 × 5 cm), and number of basis images (450 and 720) were the variables studied. Two examiners evaluated the images, and the resulting data were compared through McNemar, McNemar-Bowker, and Student t tests. Additionally, dosimetry was determined for all protocols tested, and radiation doses were compared through analysis of variance. RESULTS The variables did not influence evaluation of mandibular third molars, except for voxel size, when assessing contact between the tooth and the mandibular canal (P = .021). Although FOV and number of basis images affected radiation dose, voxel size did not. CONCLUSIONS FOV size and number of basis images did not influence the evaluation of mandibular third molars and their relationship to the mandibular canal in the CBCT unit used. Conversely, smaller voxel size affected the assessment of contact between the tooth and the mandibular canal. In units in which voxel size does not influence radiation dose, the most appropriate CBCT protocol is the one using a smaller voxel size and delivering the lowest radiation dose to the patient.
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Al-Okshi A, Theodorakou C, Lindh C. Dose optimization for assessment of periodontal structures in cone beam CT examinations. Dentomaxillofac Radiol 2017; 46:20160311. [PMID: 27910717 PMCID: PMC5606266 DOI: 10.1259/dmfr.20160311] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 11/23/2016] [Accepted: 11/28/2016] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To investigate the relationship between dose and image quality for a dedicated dental CBCT scanner using different scanning protocols and to set up an optimal imaging protocol for assessment of periodontal structures. METHODS Radiation dose and image quality measurements were made using 3D Accuitomo 170 (J. Morita, Kyoto, Japan) dental CBCT scanner. The SedentexCT IQ phantom was used to investigate the relationship between contrast-to-noise ratio (CNR) and dose-area product. Subjective image quality assessment was achieved using a small adult skull phantom for the same range of exposure settings. Five independent observers assessed the images for three anatomical landmarks using a three-point visual grade analysis. RESULTS When correlating the CNR of each scanning protocol to the exposure parameters used to obtain it, CNR decreased as these parameters decreased, especially current-exposure time product. When correlating to subjective image quality, the CNR level remained acceptable when 5 mA and 17.5 s or greater was selected and 80 kV could be used without compromising the CNR. CONCLUSIONS For a dedicated CBCT unit, changing the rotation angle from 360° to 180° degrades image quality. By altering tube potential and current for the 360° rotation protocol, assessment of periodontal structures can be performed with a smaller dose without substantially affecting visualization.
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Affiliation(s)
- Ayman Al-Okshi
- Department of Oral and Maxillofacial Radiology, Faculty of Odontology, Malmö University, Malmö, Sweden
- Department of Oral Medicine and Radiology, Faculty of Dentistry, Sebha University, Sebha, Libya
| | - Chrysoula Theodorakou
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
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Jasa GR, Shimizu M, Okamura K, Tokumori K, Takeshita Y, Weerawanich W, Yoshiura K. Effects of exposure parameters and slice thickness on detecting clear and unclear mandibular canals using cone beam CT. Dentomaxillofac Radiol 2017; 46:20160315. [PMID: 28125294 DOI: 10.1259/dmfr.20160315] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES The purpose of this study was to clarify the effects of exposure parameters and image-processing methods when using CBCT to detect clear and unclear mandibular canals (MCs). METHODS 24 dry half mandibles were divided into 2 groups with clear and unclear MCs based on a previous CBCT study. Mandibles were scanned using a CBCT system with varying exposure parameters (tube voltages 60 kV, 70 kV and 90 kV; and tube currents 2 mA, 5 mA, 10 mA and 15 mA) to obtain a total of 144 scans. The images were processed with different slice thicknesses using ImageJ software (National Institutes of Health, Bethesda, MD). Five radiologists evaluated the cross-sectional images of the first molar region to detect the MCs. The diagnostic accuracy of varying exposure parameters and image-processing conditions was compared with the area under the curve (Az) in receiver-operating characteristic analysis. RESULTS The Az values for clear MCs were higher than those for unclear MCs (p < 0.0001). With increasing exposure voltages and currents, Az values increased, but no significant differences were found with high voltages and currents in clear MCs (p = 1.0000 and p = 0.9340). The Az values of serial images were higher than those of overlaid images (p < 0.0001), and those for thicker slices were higher than those for thinner slices (p < 0.0001). CONCLUSIONS Our findings indicate that detection of unclear MCs requires either higher exposure parameters or processing of the images with thicker slices. To detect clear MCs, lower exposure parameters can be used.
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Affiliation(s)
- Gainer R Jasa
- 1 Oral Radiology Division, University of the Republic, Montevideo, Uruguay
| | - Mayumi Shimizu
- 2 Department of Oral and Maxillofacial Radiology, Kyushu University Hospital, Fukuoka, Japan
| | - Kazutoshi Okamura
- 3 Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Kenji Tokumori
- 4 Department of Radiological Technology, Faculty of Fukuoka Medical Technology, Teikyo University, Fukuoka, Japan
| | - Yohei Takeshita
- 2 Department of Oral and Maxillofacial Radiology, Kyushu University Hospital, Fukuoka, Japan
| | - Warangkana Weerawanich
- 3 Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Kazunori Yoshiura
- 3 Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
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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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Takeshita Y, Shimizu M, Okamura K, Yoshida S, Weerawanich W, Tokumori K, Jasa GR, Yoshiura K. A new method to evaluate image quality of CBCT images quantitatively without observers. Dentomaxillofac Radiol 2017; 46:20160331. [PMID: 28045343 DOI: 10.1259/dmfr.20160331] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To develop an observer-free method for quantitatively evaluating the image quality of CBCT images by applying just-noticeable difference (JND). METHODS We used two test objects: (1) a Teflon (polytetrafluoroethylene) plate phantom attached to a dry human mandible; and (2) a block phantom consisting of a Teflon step phantom and an aluminium step phantom. These phantoms had holes with different depths. They were immersed in water and scanned with a CB MercuRay (Hitachi Medical Corporation, Tokyo, Japan) at tube voltages of 120 kV, 100 kV, 80 kV and 60 kV. Superimposed images of the phantoms with holes were used for evaluation. The number of detectable holes was used as an index of image quality. In detecting holes quantitatively, the threshold grey value (ΔG), which differentiated holes from the background, was calculated using a specific threshold (the JND), and we extracted the holes with grey values above ΔG. The indices obtained by this quantitative method (the extracted hole values) were compared with the observer evaluations (the observed hole values). In addition, the contrast-to-noise ratio (CNR) of the shallowest detectable holes and the deepest undetectable holes were measured to evaluate the contribution of CNR to detectability. RESULTS The results of this evaluation method corresponded almost exactly with the evaluations made by observers. The extracted hole values reflected the influence of different tube voltages. All extracted holes had an area with a CNR of ≥1.5. CONCLUSIONS This quantitative method of evaluating CBCT image quality may be more useful and less time-consuming than evaluation by observation.
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Affiliation(s)
- Yohei Takeshita
- 1 Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Mayumi Shimizu
- 2 Department of Oral and Maxillofacial Radiology, Kyushu University Hospital, Fukuoka, Japan
| | - Kazutoshi Okamura
- 1 Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Shoko Yoshida
- 3 Section of Image Diagnostics, Department of Diagnostics and General Care, Fukuoka Dental College, Fukuoka, Japan
| | - Warangkana Weerawanich
- 1 Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Kenji Tokumori
- 4 Department of Radiological Technology, Faculty of Fukuoka Medical Technology, Teikyo University, Fukuoka, Japan
| | - Gainer R Jasa
- 5 Oral Radiology Division, Faculty of Dentistry, Republic University, Montevideo, Uruguay
| | - Kazunori Yoshiura
- 1 Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
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Wang D, He X, Wang Y, Zhou G, Sun C, Yang L, Bai J, Gao J, Wu Y, Cheng J. Topographic relationship between root apex of mesially and horizontally impacted mandibular third molar and lingual plate: cross-sectional analysis using CBCT. Sci Rep 2016; 6:39268. [PMID: 27991572 PMCID: PMC5171861 DOI: 10.1038/srep39268] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 11/21/2016] [Indexed: 11/08/2022] Open
Abstract
The present study was aimed to determine the topographic relationship between root apex of the mesially and horizontally impacted mandibular third molar and lingual plate of mandible. The original cone beam computed tomography (CBCT) data of 364 teeth from 223 patients were retrospectively collected and analyzed. The topographic relationship between root apex and lingual plate on cross-sectional CBCT images was classified as non-contact (99), contact (145) and perforation (120). The cross-sectional morphology of lingual plate at the level of root apex was defined as parallel (28), undercut (38), slanted (29) and round (4). The distribution of topographic relationship between root apex and lingual plate significantly associated with gender, impaction depth, root number and lingual plate morphology. Moreover, the average bone thickness of lingual cortex and distance between root apex and the outer surface of lingual plate were 1.02 and 1.39 mm, respectively. Furthermore, multivariate regression analyses identified impaction depth and lingual plate morphology as the risk factors for the contact and perforation subtypes between root apex and lingual plate. Collectively, our findings reveal the topographic proximity of root apex of impacted mandibular third molar to the lingual plate, which might be associated with intraoperative and postoperative complications during tooth extraction.
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Affiliation(s)
- Dongmiao Wang
- Department of Oral and Maxillofacial Surgery, College of Stomatology, Nanjing Medical University, Nanjing 210029, China
- Jiangsu Key Laboratory of Oral Disease, Nanjing Medical University, Nanjing 210029, China
| | - Xiaotong He
- Department of Oral and Maxillofacial Surgery, College of Stomatology, Nanjing Medical University, Nanjing 210029, China
| | - Yanling Wang
- Department of oral prosthodontics, College of Stomatology, Nanjing Medical University, Nanjing 210029, China
| | - Guangchao Zhou
- Department of Oral and Maxillofacial Radiology, College of Stomatology, Nanjing Medical University, Nanjing 210029, China
| | - Chao Sun
- Department of Oral and Maxillofacial Radiology, College of Stomatology, Nanjing Medical University, Nanjing 210029, China
| | - Lianfeng Yang
- Department of Oral and Maxillofacial Radiology, College of Stomatology, Nanjing Medical University, Nanjing 210029, China
| | - Jianling Bai
- Department of Biomedical Statistics, College of Public Health, Nanjing Medical University, Nanjing 210029, China
| | - Jun Gao
- Jiangsu Key Laboratory of Oral Disease, Nanjing Medical University, Nanjing 210029, China
| | - Yunong Wu
- Department of Oral and Maxillofacial Surgery, College of Stomatology, Nanjing Medical University, Nanjing 210029, China
| | - Jie Cheng
- Department of Oral and Maxillofacial Surgery, College of Stomatology, Nanjing Medical University, Nanjing 210029, China
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The impact of manual threshold selection in medical additive manufacturing. Int J Comput Assist Radiol Surg 2016; 12:607-615. [PMID: 27718124 PMCID: PMC5362669 DOI: 10.1007/s11548-016-1490-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 09/27/2016] [Indexed: 11/24/2022]
Abstract
Purpose Medical additive manufacturing requires standard tessellation language (STL) models. Such models are commonly derived from computed tomography (CT) images using thresholding. Threshold selection can be performed manually or automatically. The aim of this study was to assess the impact of manual and default threshold selection on the reliability and accuracy of skull STL models using different CT technologies. Method One female and one male human cadaver head were imaged using multi-detector row CT, dual-energy CT, and two cone-beam CT scanners. Four medical engineers manually thresholded the bony structures on all CT images. The lowest and highest selected mean threshold values and the default threshold value were used to generate skull STL models. Geometric variations between all manually thresholded STL models were calculated. Furthermore, in order to calculate the accuracy of the manually and default thresholded STL models, all STL models were superimposed on an optical scan of the dry female and male skulls (“gold standard”). Results The intra- and inter-observer variability of the manual threshold selection was good (intra-class correlation coefficients >0.9). All engineers selected grey values closer to soft tissue to compensate for bone voids. Geometric variations between the manually thresholded STL models were 0.13 mm (multi-detector row CT), 0.59 mm (dual-energy CT), and 0.55 mm (cone-beam CT). All STL models demonstrated inaccuracies ranging from −0.8 to +1.1 mm (multi-detector row CT), −0.7 to +2.0 mm (dual-energy CT), and −2.3 to +4.8 mm (cone-beam CT). Conclusions This study demonstrates that manual threshold selection results in better STL models than default thresholding. The use of dual-energy CT and cone-beam CT technology in its present form does not deliver reliable or accurate STL models for medical additive manufacturing. New approaches are required that are based on pattern recognition and machine learning algorithms.
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Katkar R, Steffy DD, Noujeim M, Deahl ST, Geha H. The effect of milliamperage, number of basis images, and export slice thickness on contrast-to-noise ratio and detection of mandibular canal on cone beam computed tomography scans: an in vitro study. Oral Surg Oral Med Oral Pathol Oral Radiol 2016; 122:646-653. [PMID: 27765335 DOI: 10.1016/j.oooo.2016.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 05/31/2016] [Accepted: 08/04/2016] [Indexed: 12/18/2022]
Abstract
OBJECTIVES The aim of this study was to evaluate the effect of milliamperage, number of basis images, and export slice thickness on contrast-to-noise ratio (CNR) and confidence in detecting mandibular canal. STUDY DESIGN Two phantoms were used. Each phantom consisted of a dry mandible with an epoxy resin bone tissue substitute block and a water-equivalent block, submerged in water. Each mandible was scanned with a Morita 3D Accuitomo cone beam computed tomography (CBCT) machine (Morita, Kyoto, Japan). Scans were made with 180-degree and 360-degree rotations, at 4, 6, and 8 mA. Each scan was exported in Digital Imaging and Communications in Medicine (DICOM) format at slice thicknesses of 0.125 mm, 0.25 mm, 0.75 mm, and 1.0 mm, resulting in 24 image sets for each phantom. The CNR was calculated. Variables were analyzed using factorial analysis of variance. The scans were also evaluated by five observers who were asked to state their confidence in detecting the mandibular canal on a four-point confidence scale. RESULTS Increasing the number of basis images, milliamperage, or export slice thickness significantly increased the CNR. Reducing the export slice thickness improved observers' confidence in detecting the mandibular canal. CONCLUSIONS The CBCT acquisition settings should be carefully chosen, depending on specific diagnostic tasks. The lowest slice thickness equal to the voxel size should always be used for exporting CBCT data despite the higher noise.
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Affiliation(s)
- Rujuta Katkar
- Assistant Professor, Department of Comprehensive Dentistry, University of Texas Health Science Center, San Antonio, TX, USA.
| | - Douglas D Steffy
- Past Resident, Department of Comprehensive Dentistry, University of Texas Health Science Center, San Antonio, TX, USA
| | - Marcel Noujeim
- Associate Professor, Department of Comprehensive Dentistry, University of Texas Health Science Center, San Antonio, TX, USA
| | - S Thomas Deahl
- Clinical Associate Professor, Department of Comprehensive Dentistry, University of Texas Health Science Center, San Antonio, TX, USA
| | - Hassem Geha
- Assistant Professor, Department of Comprehensive Dentistry, University of Texas Health Science Center, San Antonio, TX, USA
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Iikubo M, Nishioka T, Okura S, Kobayashi K, Sano T, Katsumata A, Ariji E, Kojima I, Sakamoto M, Sasano T. Influence of voxel size and scan field of view on fracture-like artifacts from gutta-percha obturated endodontically treated teeth on cone-beam computed tomography images. Oral Surg Oral Med Oral Pathol Oral Radiol 2016; 122:631-637. [PMID: 27765333 DOI: 10.1016/j.oooo.2016.07.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 06/30/2016] [Accepted: 07/22/2016] [Indexed: 12/18/2022]
Abstract
OBJECTIVE To determine the optimal scan settings (scan mode and position of field of view [FOV]) for cone beam computed tomography to reduce root fracture-like artifacts that are often observed in teeth filled with gutta-percha cones (GPCs). STUDY DESIGN Fracture-like artifacts that appeared on cone beam computed tomography images of 9 extracted human mandibular premolars filled with GPCs were analyzed using I-mode (FOV, 102 mm; voxel size, 0.2 mm) and D-mode (FOV, 51 mm; voxel size, 0.1 mm) settings. RESULTS The artificial lines were more obvious in I-mode than in D-mode. Increased distance between the center of the FOV and the GPCs produced stronger artificial lines in both I-mode and D-mode. CONCLUSION To reduce fracture-like artifacts, it is critical to use a mode with small voxel size and to place the target tooth in the center of the FOV.
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Affiliation(s)
- Masahiro Iikubo
- Department of Oral Diagnosis, Tohoku University Graduate School of Dentistry, Sendai, Japan.
| | - Takashi Nishioka
- Department of Oral Diagnosis, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Shintaro Okura
- Department of Oral and Maxillofacial Radiology and Diagnosis, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Kaoru Kobayashi
- Department of Oral and Maxillofacial Radiology and Diagnosis, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Tsukasa Sano
- Department of Oral and Maxillofacial Radiology and Diagnosis, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Akitoshi Katsumata
- Department of Oral Radiology, Asahi University School of Dentistry, Mizuho, Japan
| | - Eiichiro Ariji
- Department of Oral and Maxillofacial Radiology, Aichi-Gakuin University School of Dentistry, Nagoya, Japan
| | - Ikuho Kojima
- Department of Oral Diagnosis, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Maya Sakamoto
- Department of Oral Diagnosis, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Takashi Sasano
- Department of Oral Diagnosis, Tohoku University Graduate School of Dentistry, Sendai, Japan
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214
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External root resorption of the second molar associated with mesially and horizontally impacted mandibular third molar: evidence from cone beam computed tomography. Clin Oral Investig 2016; 21:1335-1342. [PMID: 27316639 DOI: 10.1007/s00784-016-1888-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 06/14/2016] [Indexed: 10/21/2022]
Abstract
OBJECTIVES The aim of the present study was to assess the incidence and risk factors of ERR in second molars with mesially and horizontally impacted mandibular third molars using cone beam computed tomography (CBCT) images from patients in a Chinese tertiary referral hospital. MATERIALS AND METHODS A total number of 216 patients with 362 mesially and horizontally impacted mandibular third molars who were treated at our institution from 2014 to 2015 was retrospectively included. The ERR in second molars was identified on CBCT multiplanar images. The associations between incidence of ERR and multiple clinical parameters were statistically analyzed by Chi-square test. Moreover, the risk factors for ERR in second molars were further assessed by multivariate regression analysis. RESULTS The overall incidence of ERR in second molars was 20.17 % (73/362) as detected on CBCT images. The presence of ERR significantly associated with patients age and impaction depth of mandibular third molars. However, no significant relationship was found between ERR severity and impaction depth or ERR location. Multivariate regression analyses further revealed age over 35 years and impaction depth as important risk factors affecting the ERR incidence caused by mesial and horizontal impaction of mandibular third molar. CONCLUSIONS ERR in second molar resulted from mesially and horizontally impacted mandibular third molar is not very rare and can be reliably identified via CBCT scan. CLINICAL RELEVANCE Given the possibility of ERR associated with third molar impaction, the prophylactic removal of these impacted teeth could be considered especially for those patients with over 35 years and mesially and horizontally impacted teeth.
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215
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Panjnoush M, Kheirandish Y, Kashani PM, Fakhar HB, Younesi F, Mallahi M. Effect of Exposure Parameters on Metal Artifacts in Cone Beam Computed Tomography. JOURNAL OF DENTISTRY (TEHRAN, IRAN) 2016; 13:143-150. [PMID: 28392810 PMCID: PMC5376540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
OBJECTIVES The aim of this study was to assess the effect of tube current, kilovoltage peak (kVp), metal type, and the position of metal objects on metal artifacts in cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS Titanium and cobalt-chromium rods were fabricated and placed in a dry human mandible. Samples were scanned using a Promax 3D CBCT unit with different milli-amperages and kVp. The artifacts induced by metal objects were evaluated using the Image J software in four regions of interest (ROIs) on each image. RESULTS A higher kVp decreased artifacts of the buccal surface of the rods in 97% of the cases (P=0.046) but did not affect the severity of artifacts between the two metal objects (P>0.05). Increasing the tube current had no effect on metal artifacts in 93% of the cases (P>0.05). Artifacts induced by a cobalt-chromium alloy were more severe than those with titanium (P<0.001). Artifacts were more intense in the buccal surface of anterior rods compared to the posterior rods (P<0.003). CONCLUSIONS Tube voltage, metal type and the position of metal objects affected the severity of metal artifacts on CBCT images. The metal type had the greatest effect on metal artifact intensity in this study.
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Affiliation(s)
- Mehrdad Panjnoush
- Assistant Professor, Department of Oral and Maxillofacial Radiology, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Yasaman Kheirandish
- Assistant Professor, Department of Oral and Maxillofacial Radiology, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Pooneh Mohseni Kashani
- Postgraduate Student, Department of Oral and Maxillofacial Radiology, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran,Corresponding author: P. Mohseni Kashani, Department of Oral and Maxillofacial, Faculty of Dentistry, Tehran, Iran
| | - Hoorieh Bashizadeh Fakhar
- Assistant Professor, Department of Oral and Maxillofacial Radiology, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Farzan Younesi
- Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Azad University, Tehran, Iran
| | - Maysa Mallahi
- Postgraduate Student, Department of Oral and Maxillofacial Radiology, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
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216
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Hwang JJ, Park H, Jeong HG, Han SS. Change in Image Quality According to the 3D Locations of a CBCT Phantom. PLoS One 2016; 11:e0153884. [PMID: 27093639 PMCID: PMC4836729 DOI: 10.1371/journal.pone.0153884] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 04/05/2016] [Indexed: 12/22/2022] Open
Abstract
A patient's position changes in every CBCT scan despite patient alignment protocols. However, there have been studies to determine image quality differences when an object is located at the center of the field of view (FOV). To evaluate changes in the image quality of the CBCT scan according to different object positions, the image quality indexes of the Alphard 3030 (Alphard Roentgen Ind., Ltd., Kyoto, Japan) and the Rayscan Symphony (RAY Ind., Ltd., Suwon, Korea) were measured using the Quart DVT_AP phantom at the center of the FOV and 6 peripheral positions under four types of exposure conditions. Anterior, posterior, right, left, upper, and lower positions 1 cm offset from the center of the FOV were used for the peripheral positions. We evaluated and compared the voxel size, homogeneity, contrast to noise ratio (CNR), and the 10% point of the modulation transfer function (MTF10%) of the center and periphery. Because the voxel size, which is determined by the Nyquist frequency, was within tolerance, other image quality indexes were not influenced by the voxel size. For the CNR, homogeneity, and MTF10%, there were peripheral positions which showed considerable differences with statistical significance. The average difference between the center and periphery was up to 31.27% (CNR), 70.49% (homogeneity), and 13.64% (MTF10%). Homogeneity was under tolerance at some of the peripheral locations. Because the CNR, homogeneity, and MTF10% were significantly affected by positional changes of the phantom, an object's position can influence the interpretation of follow up CBCT images. Therefore, efforts to locate the object in the same position are important.
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Affiliation(s)
- Jae Joon Hwang
- Department of Oral and Maxillofacial Radiology, College of Dentistry, Yonsei University, Seoul, Korea
| | - Hyok Park
- Department of Oral and Maxillofacial Radiology, College of Dentistry, Yonsei University, Seoul, Korea
| | - Ho-Gul Jeong
- Department of Oral and Maxillofacial Radiology, College of Dentistry, Yonsei University, Seoul, Korea
| | - Sang-Sun Han
- Department of Oral and Maxillofacial Radiology, College of Dentistry, Yonsei University, Seoul, Korea
- * E-mail:
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217
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Bhatia S, Kohli S. Cone-beam computed tomography usage: An alert to the field of dentistry. Imaging Sci Dent 2016; 46:145-6. [PMID: 27358823 PMCID: PMC4925652 DOI: 10.5624/isd.2016.46.2.145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 02/12/2016] [Accepted: 02/24/2016] [Indexed: 11/24/2022] Open
Affiliation(s)
- Shekhar Bhatia
- Division of Clinical Dentistry, School of Dentistry, International Medical University, Kuala Lumpur, Malaysia
| | - Shivani Kohli
- Department of Prosthodontics, MAHSA University, Kuala Lumpur, Malaysia
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218
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219
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Kiljunen T, Kaasalainen T, Suomalainen A, Kortesniemi M. Dental cone beam CT: A review. Phys Med 2015; 31:844-860. [PMID: 26481816 DOI: 10.1016/j.ejmp.2015.09.004] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 09/15/2015] [Accepted: 09/19/2015] [Indexed: 11/17/2022] Open
Abstract
For the maxillofacial region, there are various indications that cannot be interpreted from 2D images and will benefit from multiplanar viewing. Dental cone beam CT (CBCT) utilises a cone- or pyramid-shaped X-ray beam using mostly flat-panel detectors for 3D image reconstruction with high spatial resolution. The vast increase in availability and amount of these CBCT devices offers many clinical benefits, and their ongoing development has potential to bring various new clinical applications for medical imaging. Additionally, there is also a need for high quality research and education. European guidelines promote the use of a medical physics expert for advice on radiation protection, patient dose optimisation, and equipment testing. In this review article, we perform a comparison of technical equipment based on manufacturer data, including scanner specific X-ray spectra, and describe issues concerning CBCT image reconstruction and image quality, and also address radiation dose issues, dosimetry, and optimisation. We also discuss clinical needs and what type of education users should have in order to operate CBCT systems safely. We will also take a look into the future and discuss the issues that still need to be solved.
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Affiliation(s)
- Timo Kiljunen
- Docrates Cancer Center, Saukonpaadenranta 2, 00180 Helsinki, Finland.
| | - Touko Kaasalainen
- HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 4, 00290 Helsinki, Finland
| | - Anni Suomalainen
- HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 4, 00290 Helsinki, Finland
| | - Mika Kortesniemi
- HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 4, 00290 Helsinki, Finland
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220
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Pauwels R, Jacobs R, Bogaerts R, Bosmans H, Panmekiate S. Reduction of scatter-induced image noise in cone beam computed tomography: effect of field of view size and position. Oral Surg Oral Med Oral Pathol Oral Radiol 2015; 121:188-95. [PMID: 26792756 DOI: 10.1016/j.oooo.2015.10.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/01/2015] [Accepted: 10/12/2015] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To measure the effect of field of view (FOV) size and position on scatter-induced image noise in cone beam computed tomography (CBCT). STUDY DESIGN A polymethyl methacrylate (PMMA) phantom containing air and aluminum underwent CBCT scanning, using seven FOVs ranging between 4 × 4 cm and 14 × 10 cm, positioned both centrally and according to a dental scan. Signal difference to noise ratio (SDNR) was measured on two-dimensional (2-D) projection images. RESULTS At a central position, SDNR decreased with increasing FOV size, ranging between 9.8 (14 × 10 cm) and 10.9 (4 × 4 cm). For dental FOV positions, SDNR values were between 6.3 (14 × 10 cm) and 9.5 (4 × 4 cm). To reach a constant SDNR, a dose reduction up to 76% was possible for small FOVs compared with the 14 × 10 cm FOV. CONCLUSIONS The use of small FOVs and peripheral FOV positioning decreases scatter at the detector, resulting in a considerable potential for reduction of radiation dose to the patient.
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Affiliation(s)
- Ruben Pauwels
- Lecturer, Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand; OMFS-IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, University of Leuven and Department of Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium.
| | - Reinhilde Jacobs
- Professor, OMFS-IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, University of Leuven and Department of Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Ria Bogaerts
- Professor, Laboratory of Experimental Radiotherapy, Department of Oncology, Biomedical Sciences Group, University of Leuven, Leuven, Belgium
| | - Hilde Bosmans
- Professor, Medical Physics & Quality Assessment, Department of Imaging and Pathology, Biomedical Sciences Group, University of Leuven, Leuven, Belgium
| | - Soontra Panmekiate
- Professor and Head, Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
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221
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Pauwels R, Jacobs R, Singer SR, Mupparapu M. CBCT-based bone quality assessment: are Hounsfield units applicable? Dentomaxillofac Radiol 2015; 44:20140238. [PMID: 25315442 DOI: 10.1259/dmfr.20140238] [Citation(s) in RCA: 219] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
CBCT is a widely applied imaging modality in dentistry. It enables the visualization of high-contrast structures of the oral region (bone, teeth, air cavities) at a high resolution. CBCT is now commonly used for the assessment of bone quality, primarily for pre-operative implant planning. Traditionally, bone quality parameters and classifications were primarily based on bone density, which could be estimated through the use of Hounsfield units derived from multidetector CT (MDCT) data sets. However, there are crucial differences between MDCT and CBCT, which complicates the use of quantitative gray values (GVs) for the latter. From experimental as well as clinical research, it can be seen that great variability of GVs can exist on CBCT images owing to various reasons that are inherently associated with this technique (i.e. the limited field size, relatively high amount of scattered radiation and limitations of currently applied reconstruction algorithms). Although attempts have been made to correct for GV variability, it can be postulated that the quantitative use of GVs in CBCT should be generally avoided at this time. In addition, recent research and clinical findings have shifted the paradigm of bone quality from a density-based analysis to a structural evaluation of the bone. The ever-improving image quality of CBCT allows it to display trabecular bone patterns, indicating that it may be possible to apply structural analysis methods that are commonly used in micro-CT and histology.
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Affiliation(s)
- R Pauwels
- 1 Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
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222
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Pinheiro LR, Scarfe WC, Augusto de Oliveira Sales M, Gaia BF, Cortes ARG, Cavalcanti MG. Effect of Cone-Beam Computed Tomography Field of View and Acquisition Frame on the Detection of Chemically Simulated Peri-Implant Bone Loss In Vitro. J Periodontol 2015; 86:1159-65. [PMID: 26156676 DOI: 10.1902/jop.2015.150223] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND The aim of this study is to determine the influence of field of view (FOV) and number of acquisition projection images (frames) on the detection of chemically simulated peri-implant defects by cone-beam computed tomography (CBCT) using an in vitro bovine rib bone model. METHODS Eighty implants were placed in bovine ribs in which small and large bone defects were created using 70% perchloric acid. CBCT images were acquired at three acquisition protocols: protocol 1 (FOV 4 × 4 cm, 0.08-mm voxel size, 1,009 frames [high fidelity]; protocol 2 (same as protocol 1 except 512 frames [standard]); and protocol 3 (FOV 14 × 5 cm, 0.25-mm voxel size; high fidelity). Two oral and maxillofacial radiologists (OMRs) and two oral and maxillofacial surgeons (OMSs) rated the presence or absence of bone defects on a five-point scale. κ and area under the curve (AUC) were calculated and compared using analysis of variance with post hoc Tukey test at P ≤ 0.05. RESULTS Intra- and interobserver agreement for OMRs ranged from moderate to good and from slight to moderate for OMSs. For the detection of small lesions, protocol 1 (AUC 0.813 ± 0.045) provided higher detection rates than protocol 2 (AUC 0.703 ± 0.02) and protocol 3 (AUC 0.773 ± 0.55) [F(2,9) = 1.6377]. For larger defects, the trends were similar, with protocol 1 (AUC 0.852 ± 0.108) providing higher detection rates than protocol 2 (AUC 0.730 ± 0.045) and protocol 3 (AUC 0.783 ± 0.058) [F(2,9) = 1.9576]. CONCLUSION Within the limits of this study, optimal detection of chemically simulated pericircumferential implant crestal bone defects is achieved at the least radiation detriment using the smallest FOV, the highest number of acquisition frames, and the smallest voxel.
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Affiliation(s)
- Lucas Rodrigues Pinheiro
- Department of Surgical and Hospital Dentistry, University of Louisville School of Dentistry, Louisville, Kentucky.,Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - William C Scarfe
- Department of Surgical and Hospital Dentistry, University of Louisville School of Dentistry, Louisville, Kentucky
| | | | - Bruno Felipe Gaia
- Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil
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223
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Pinheiro LR, Gaia BF, Oliveira de Sales MA, Umetsubo OS, Santos Junior O, Paraíso Cavalcanti MG. Effect of field of view in the detection of chemically created peri-implant bone defects in bovine ribs using cone beam computed tomography: an in vitro study. Oral Surg Oral Med Oral Pathol Oral Radiol 2015; 120:69-77. [DOI: 10.1016/j.oooo.2015.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 03/18/2015] [Accepted: 04/13/2015] [Indexed: 01/17/2023]
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224
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Pauwels R, Faruangsaeng T, Charoenkarn T, Ngonphloy N, Panmekiate S. Effect of exposure parameters and voxel size on bone structure analysis in CBCT. Dentomaxillofac Radiol 2015; 44:20150078. [PMID: 26054572 DOI: 10.1259/dmfr.20150078] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To evaluate the effect of exposure parameters and voxel size on bone structure analysis in dental CBCT. METHODS 20 cylindrical bone samples underwent CBCT scanning (3D Accuitomo 170; J. Morita, Kyoto, Japan) using three combinations of tube voltage (kV) and tube current-exposure time product (mAs), corresponding with a CT dose index of 3.4 mGy: 90 kV and 62 mAs, 73 kV and 108.5 mAs, and 64 kV and 155 mAs. Images were reconstructed with a voxel size of 0.080 mm. In addition, the 90 kV scan was reconstructed at voxel sizes of 0.125, 0.160, 0.200, 0.250 and 0.300 mm. The following parameters were measured: bone surface (BS) and bone volume (BV) per total volume (TV), fractal dimension, connectivity density, anisotropy, trabecular thickness (Tb. Th.) and trabecular spacing (Tb. Sp.), structure model index (SMI), plateness, branches, junctions, branch length and triple points. RESULTS For most parameters, there was no significant effect of the kV value. For BV/TV, "90 kV" differed significantly from the other kV settings; for SMI, "64 vs 73 kV" was significant. For BS/TV, fractal dimension, connectivity density, branches, junctions and triple points values incrementally decreased at larger voxel sizes, whereas an increase was seen for Tb. Th., Tb. Sp., SMI and branch length. For anisotropy and plateness, no (or little) effect of voxel size was seen; for BV/TV, the effect was inconsistent. CONCLUSIONS Most bone structure parameters are not affected by the kV if the radiation dose is constant. Parameters dealing with the trabecular structure are heavily affected by the voxel size.
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Affiliation(s)
- R Pauwels
- 1 Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.,2 OMFS-IMPATH Research Group, Oral Imaging Center, Department of Imaging and Pathology, Biomedical Sciences Group, University of Leuven, Leuven, Belgium
| | - T Faruangsaeng
- 1 Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - T Charoenkarn
- 1 Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - N Ngonphloy
- 1 Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - S Panmekiate
- 1 Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
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