501
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Yasuda M, Yoshikawa K, Kato K, Sai S, Sakiyama K, Kobayashi Y, Oosawa M, Sato H, Matsumoto H, Nakazawa Y. Validation of a Metal Artifact Reduction Algorithm Using 1D Linear Interpolation for Cone Beam CT after Endovascular Coiling Therapy for Cerebral Aneurysms. Neuroradiol J 2014; 27:742-54. [PMID: 25489899 DOI: 10.15274/nrj-2014-10102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 09/23/2014] [Indexed: 11/12/2022] Open
Abstract
This study aimed to evaluate the effect of a metal artifact reduction (MAR) algorithm using 1D linear interpolation on cone-beam CT (CBCT). We performed phantom and clinical qualitative studies with and without MAR application using 1D linear interpolation. In the phantom study, the standard deviation (SD) was estimated from the images obtained from the water phantom in which a metal coil was placed at the center, and observed the changes in the SDs before and after MAR application. In the clinical qualitative study, the clinical images after endovascular treatment (EVT) for cerebral aneurysms were visually evaluated before and after MAR application. In the phantom study, the SDs after MAR application decreased by 56 to 35% compared with that before MAR application. In the clinical qualitative study, the artifacts from the metal coil decreased or increased depending on locations, and the contrasts of gray matter and white matter were attenuated when MAR was applied. In conclusion, the metal artifact decreases when MAR using 1D linear interpolation is applied to cerebral CBCT. However, another artifacts increase or soft tissue contrast is changed in some cases. MAR largely contributes to the reduction of streaking artifacts, whereas it may induce cerebral parenchyma at distant metal body or quality deterioration of the image not including the metal body. This should be taken into account in the diagnosis of secondary hemorrhage or infarction.
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Affiliation(s)
- Mitsuyoshi Yasuda
- Graduate Division of Health Sciences, Komazawa University; Tokyo, Japan - Department of Radiological Technology, Showa University Koto-Toyosu Hospital; Tokyo, Japan -
| | - Kohki Yoshikawa
- Graduate Division of Health Sciences, Komazawa University; Tokyo, Japan
| | - Kyoichi Kato
- Graduate School of Nursing and Rehabilitation Sciences, Showa University; Tokyo, Japan
| | - Shogo Sai
- Department of Radiological Technology, Showa University Koto-Toyosu Hospital; Tokyo, Japan
| | - Koshi Sakiyama
- Department of Radiological Technology, Showa University Fujigaoka Hospital; Kanagawa, Japan
| | - Yoshifumi Kobayashi
- Department of Radiological Technology, Showa University Fujigaoka Hospital; Kanagawa, Japan
| | - Miwa Oosawa
- Department of Radiological Technology, Showa University Hospital; Tokyo, Japan
| | - Hisaya Sato
- Graduate School of Nursing and Rehabilitation Sciences, Showa University; Tokyo, Japan
| | - Hiroaki Matsumoto
- Department of Neurological Surgery, Showa University Fujigaoka Hospital; Kanagawa, Japan
| | - Yasuo Nakazawa
- Graduate School of Nursing and Rehabilitation Sciences, Showa University; Tokyo, Japan
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502
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Todd R. Dental imaging-2D to 3D: a historic, current, and future view of projection radiography. ACTA ACUST UNITED AC 2014. [DOI: 10.1111/etp.12067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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503
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Vasconcelos KF, Nicolielo LFP, Nascimento MC, Haiter-Neto F, Bóscolo FN, Van Dessel J, EzEldeen M, Lambrichts I, Jacobs R. Artefact expression associated with several cone-beam computed tomographic machines when imaging root filled teeth. Int Endod J 2014; 48:994-1000. [DOI: 10.1111/iej.12395] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 10/08/2014] [Indexed: 11/30/2022]
Affiliation(s)
- K. F. Vasconcelos
- OMFS IMPATH Research Group; Department of Imaging & Pathology; Faculty of Medicine; University of Leuven and Oral & Maxillofacial Surgery; University Hospitals Leuven; Leuven Belgium
- Department of Oral Diagnosis; Division of Oral Radiology; Piracicaba Dental School; State University of Campinas; Piracicaba Brazil
| | - L. F. P. Nicolielo
- OMFS IMPATH Research Group; Department of Imaging & Pathology; Faculty of Medicine; University of Leuven and Oral & Maxillofacial Surgery; University Hospitals Leuven; Leuven Belgium
| | - M. C. Nascimento
- OMFS IMPATH Research Group; Department of Imaging & Pathology; Faculty of Medicine; University of Leuven and Oral & Maxillofacial Surgery; University Hospitals Leuven; Leuven Belgium
- Department of Oral Diagnosis; Division of Oral Radiology; Piracicaba Dental School; State University of Campinas; Piracicaba Brazil
| | - F. Haiter-Neto
- Department of Oral Diagnosis; Division of Oral Radiology; Piracicaba Dental School; State University of Campinas; Piracicaba Brazil
| | - F. N. Bóscolo
- Department of Oral Diagnosis; Division of Oral Radiology; Piracicaba Dental School; State University of Campinas; Piracicaba Brazil
| | - J. Van Dessel
- OMFS IMPATH Research Group; Department of Imaging & Pathology; Faculty of Medicine; University of Leuven and Oral & Maxillofacial Surgery; University Hospitals Leuven; Leuven Belgium
| | - M. EzEldeen
- OMFS IMPATH Research Group; Department of Imaging & Pathology; Faculty of Medicine; University of Leuven and Oral & Maxillofacial Surgery; University Hospitals Leuven; Leuven Belgium
| | - I. Lambrichts
- Biomedical Research Institute; Laboratory of Morphology; Hasselt University; Diepenbeek Belgium
| | - R. Jacobs
- OMFS IMPATH Research Group; Department of Imaging & Pathology; Faculty of Medicine; University of Leuven and Oral & Maxillofacial Surgery; University Hospitals Leuven; Leuven Belgium
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504
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Corbella S, Del Fabbro M, Tamse A, Rosen E, Tsesis I, Taschieri S. Cone beam computed tomography for the diagnosis of vertical root fractures: a systematic review of the literature and meta-analysis. Oral Surg Oral Med Oral Pathol Oral Radiol 2014; 118:593-602. [DOI: 10.1016/j.oooo.2014.07.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 06/24/2014] [Accepted: 07/29/2014] [Indexed: 11/29/2022]
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505
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Spin-Neto R, Gotfredsen E, Wenzel A. Standardized method to quantify the variation in voxel value distribution in patient-simulated CBCT data sets. Dentomaxillofac Radiol 2014; 44:20140283. [PMID: 25354021 PMCID: PMC4614169 DOI: 10.1259/dmfr.20140283] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/29/2014] [Accepted: 10/28/2014] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To suggest a standardized method to assess the variation in voxel value distribution in patient-simulated CBCT data sets and the effect of time between exposures (TBE). Additionally, a measurement of reproducibility, Aarhus measurement of reproducibility (AMORe), is introduced, which could be used for quality assurance purposes. METHODS Six CBCT units were tested [Cranex(®) 3D/CRAN (Soredex Oy, Tuusula, Finland); Scanora(®) 3D/SCAN (Soredex Oy); NewTom™ 5G/NEW5 (QR srl, Verona, Italy); i-CAT/ICAT (Imaging Sciences International, Hatfield, PA); 3D Accuitomo FPD80/ACCU (Morita, Kyoto, Japan); and NewTom VG/NEWV (QR srl)]. Two sets of volumetric data of a wax-imbedded dry human skull (containing a titanium implant) were acquired by each CBCT unit at two sessions on separate days. Each session consisted 21 exposures: 1 "initial" followed by a 30-min interval (initial data set), 10 acquired with 30-min TBE (data sets 1-10) and 10 acquired with 15-min TBE (data sets 11-20). CBCT data were exported as digital imaging and communications in medicine files and converted to text files containing x, y and z positions and grey shade for each voxel. Subtractions were performed voxel-by-voxel in two set-ups: (1) between two consecutive data sets and (2) between any subsequent data set and data set 1. The mean grey shade variation for each voxel was calculated for each unit/session. RESULTS The largest mean grey shade variation was found in the subtraction set-up 2 (27-447 shades of grey, depending on the unit). Considering subtraction set-up 1, the highest variation was seen for NEW5, between data sets 1 and the initial. CONCLUSIONS Discrepancies in voxel value distribution were found by comparing the initial examination of the day with the subsequent examinations. TBE had no predictable effect on the variation of CBCT-derived voxel values. AMORe ranged between 0 and 64.
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Affiliation(s)
- R Spin-Neto
- Oral Radiology, Department of Dentistry, Aarhus University, Aarhus, Denmark
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506
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Kruse C, Spin-Neto R, Wenzel A, Kirkevang LL. Cone beam computed tomography and periapical lesions: a systematic review analysing studies on diagnostic efficacy by a hierarchical model. Int Endod J 2014; 48:815-28. [DOI: 10.1111/iej.12388] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 09/30/2014] [Indexed: 11/27/2022]
Affiliation(s)
- C. Kruse
- Oral Radiology; Department of Dentistry; Aarhus University; Aarhus Denmark
| | - R. Spin-Neto
- Oral Radiology; Department of Dentistry; Aarhus University; Aarhus Denmark
| | - A. Wenzel
- Oral Radiology; Department of Dentistry; Aarhus University; Aarhus Denmark
- Radiology; Department of Dentistry; Copenhagen University; Copenhagen Denmark
| | - L.-L. Kirkevang
- Oral Radiology; Department of Dentistry; Aarhus University; Aarhus Denmark
- Department of Endodontics; Institute of Clinical Dentistry; Faculty of Dentistry; Oslo University; Oslo Norway
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507
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Da Silveira PF, Fontana MP, Oliveira HW, Vizzotto MB, Montagner F, Silveira HL, Silveira HE. CBCT-based volume of simulated root resorption - influence of FOV and voxel size. Int Endod J 2014; 48:959-65. [PMID: 25283786 DOI: 10.1111/iej.12390] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 09/30/2014] [Indexed: 01/09/2023]
Abstract
AIM To examine the influence of the field of view (FOV) and voxel size on the measurement of the volume of simulated internal root resorption (IRR) lesions through cone-beam computed tomography (CBCT). METHODOLOGY Eleven single-rooted teeth with IRR simulated by acid demineralization were studied. CBCT images were acquired using large FOV (voxel sizes of 0.200, 0.250 and 0.300 mm) and limited FOV (voxel sizes of 0.076, 0.100 and 0.200 mm). The IRR volumes were calculated using the Dolphin(®) software. Volumetric measurements were validated using IRR silicone putty casts. The analysis of variance (anova) for randomized block design complemented with the Tukey's test was employed. RESULTS IRR volumes obtained using voxel sizes of 0.200 and 0.250 mm were similar (P > 0.05). However, both these values were significantly different from that obtained using the 0.300-mm voxel (P < 0.05). There was no significant difference between IRR volumes measured through voxel sizes of 0.076 and 0.100 mm (P > 0.05), but both differed significantly from that obtained through the 0.200-mm voxel (P < 0.05). There was no significant difference between the volumetric measurements of the 0.200-mm voxel images of the restricted and large FOV protocols. The mean volumes of the silicone casts were smaller than those calculated using a 0.200-mm voxel, but were similar to those obtained using voxel sizes of 0.076 and 0.300 mm. CONCLUSIONS Despite the FOV protocol, voxel size can influence measurement of simulated IRR volumes. The importance of standardization of CBCT image acquisition protocols is emphasized, especially during follow-up of an IRR lesion, to prevent misinterpretation of its extent, which can create a bias in clinical decisions.
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Affiliation(s)
- P F Da Silveira
- Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - M P Fontana
- Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - H W Oliveira
- Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - M B Vizzotto
- Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - F Montagner
- Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - H L Silveira
- Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - H E Silveira
- Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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508
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Kuusisto N, Vallittu PK, Lassila LVJ, Huumonen S. Evaluation of intensity of artefacts in CBCT by radio-opacity of composite simulation models of implants in vitro. Dentomaxillofac Radiol 2014; 44:20140157. [PMID: 25283364 DOI: 10.1259/dmfr.20140157] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES The aim was to compare the intensity of artefacts in CBCT images caused by different percentages of radio-opacifying material in composite simulation models of implants. Titanium and zirconia models of implants were used as a reference for the evaluation of the intensity of artefacts. METHODS Seven different percentages of radio-opacifying BaAlSiO2 fillers were added to composite resin to fabricate seven step wedges and simulation models of implants. Titanium and zirconia simulation models of implants were also fabricated. Aluminium step wedge was used as a reference for the measurement of grey values in intraoral radiographs. Step wedges were exposed with a Planmeca Intra X-ray machine (Planmeca Oy, Helsinki, Finland). All composite, titanium and zirconia simulation models of implants were exposed with a SCANORA(®) 3D dental X-ray machine (Soredex, Tuusula, Finland). Images and grey values were analysed with ImageJ software (National Institutes of Health, Bethesda, MD). To demonstrate possible artefacts between all the simulation models of implants, the images were also visually compared with each other using ImageJ software. RESULTS Artefacts were clearly present in CBCT images caused by titanium and zirconia and when the composite material consisted at least 20% BaAlSiO2. The intensity of artefacts increased when the radio-opacity of the composite material increased. CONCLUSIONS Materials containing less radio-opacity produce less pronounced artefacts. The cut-off point for artefacts is at 20% radio-opaque filling material in composite material.
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Affiliation(s)
- N Kuusisto
- 1 Department of Oral Pathology and Radiology, Institute of Dentistry, University of Turku, Turku, Finland
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509
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Evaluation of Cone-beam Computed Tomography in the Diagnosis of Vertical Root Fractures: The Influence of Imaging Modes and Root Canal Materials. J Endod 2014; 40:1530-6. [DOI: 10.1016/j.joen.2014.06.012] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/27/2014] [Accepted: 06/14/2014] [Indexed: 11/22/2022]
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510
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Chavda R, Mannocci F, Andiappan M, Patel S. Comparing the In Vivo Diagnostic Accuracy of Digital Periapical Radiography with Cone-beam Computed Tomography for the Detection of Vertical Root Fracture. J Endod 2014; 40:1524-9. [DOI: 10.1016/j.joen.2014.05.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 05/18/2014] [Accepted: 05/26/2014] [Indexed: 11/30/2022]
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511
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Nabha W, Hong YM, Cho JH, Hwang HS. Assessment of metal artifacts in three-dimensional dental surface models derived by cone-beam computed tomography. Korean J Orthod 2014; 44:229-35. [PMID: 25309862 PMCID: PMC4192524 DOI: 10.4041/kjod.2014.44.5.229] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 11/18/2022] Open
Abstract
Objective The aim of this study was to assess artifacts induced by metallic restorations in three-dimensional (3D) dental surface models derived by cone-beam computed tomography (CBCT). Methods Fifteen specimens, each with four extracted human premolars and molars embedded in a plaster block, were scanned by CBCT before and after the cavitated second premolars were restored with dental amalgam. Five consecutive surface models of each specimen were created according to increasing restoration size: no restoration (control) and small occlusal, large occlusal, disto-occlusal, and mesio-occluso-distal restorations. After registering each restored model with the control model, maximum linear discrepancy, area, and intensity of the artifacts were measured and compared. Results Artifacts developed mostly on the buccal and lingual surfaces. They occurred not only on the second premolar but also on the first premolar and first molar. The parametric values increased significantly with increasing restoration size. Conclusions Metallic restorations induce considerable artifacts in 3D dental surface models. Artifact reduction should be taken into consideration for a proper diagnosis and treatment planning when using 3D surface model derived by CBCT in dentofacial deformity patients.
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Affiliation(s)
- Wael Nabha
- Department of Orthodontics, School of Dentistry, Chonnam National University, Gwangju, Korea
| | - Young-Min Hong
- Department of Orthodontics, School of Dentistry, Chonnam National University, Gwangju, Korea
| | - Jin-Hyoung Cho
- Department of Orthodontics, School of Dentistry, Dental Science Research Institute, Chonnam National University, Gwangju, Korea
| | - Hyeon-Shik Hwang
- Department of Orthodontics, School of Dentistry, Dental Science Research Institute, Chonnam National University, Gwangju, Korea
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512
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Pitfalls of cone beam computed tomography in prostate artery embolization. Cardiovasc Intervent Radiol 2014; 37:1430-5. [PMID: 25189663 DOI: 10.1007/s00270-014-0982-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Accepted: 07/27/2014] [Indexed: 12/12/2022]
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513
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Campos MJDS, de Souza TS, Mota Júnior SL, Fraga MR, Vitral RWF. Bone mineral density in cone beam computed tomography: Only a few shades of gray. World J Radiol 2014; 6:607-12. [PMID: 25170398 PMCID: PMC4147441 DOI: 10.4329/wjr.v6.i8.607] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 03/11/2014] [Accepted: 04/25/2014] [Indexed: 02/06/2023] Open
Abstract
Cone beam computed tomography (CBCT) has often been used to determine the quality of craniofacial bone structures through the determination of mineral density, which is based on gray scales of the images obtained. However, there is no consensus regarding the accuracy of the determination of the gray scales in these exams. This study aims to provide a literature review concerning the reliability of CBCT to determine bone mineral density. The gray values obtained with CBCT show a linear relationship with the attenuation coefficients of the materials, Hounsfield Units values obtained with medical computed tomography, and density values from dual energy X-ray absorciometry. However, errors are expected when CBCT images are used to define the quality of the scanned structures because these images show inconsistencies and arbitrariness in the gray values, particularly when related to abrupt change in the density of the object, X-ray beam hardening effect, scattered radiation, projection data discontinuity-related effect, differences between CBCT devices, changes in the volume of the field of view (FOV), and changes in the relationships of size and position between the FOV and the object evaluated. A few methods of mathematical correction of the gray scales in CBCT have been proposed; however, they do not generate consistent values that are independent of the devices and their configurations or of the scanned objects. Thus, CBCT should not be considered the examination of choice for the determination of bone and soft tissue mineral density at the current stage, particularly when values obtained are to be compared to predetermined standard values. Comparisons between symmetrically positioned structures inside the FOV and in relation to the exomass of the object, as it occurs with the right and left sides of the skull, seem to be viable because the effects on the gray scale in the regions of interest are the same.
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514
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Parsa A, Ibrahim N, Hassan B, Syriopoulos K, van der Stelt P. Assessment of metal artefact reduction around dental titanium implants in cone beam CT. Dentomaxillofac Radiol 2014; 43:20140019. [PMID: 25135316 DOI: 10.1259/dmfr.20140019] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES The aim of this study was to investigate if the metal artefact reduction (MAR) tool used in the software of the ORTHOPANTOMOGRAPH(®) OP300 (Instrumentarium Dental, Tuusula, Finland) can improve the gray value levels in post-operative implant scans. METHODS 20 potential implant sites were selected from 5 edentulous human dry mandibles. Each mandible was scanned by a CBCT scanner, and images were produced under three different conditions: implant sites drilled but no implants inserted, implants inserted without application of MAR and implants inserted with application of MAR. Using Geomagic(®) Studio 2012 (Geomagic, Morrisville, NC) and 3Diagnosys(®) v. 5.3.1 (3Diemme(®) SRL, Cantù, Italy) software, three scans of each mandible were superimposed. The mean gray value of identical regions of bone around the implants was derived for each condition. The differences between gray value measurements at implant sites derived from different conditions were assessed. RESULTS A significant difference was found between mean gray values from the scans with no implants inserted and with implants inserted (with and without MAR) (p = 0.012). No significant difference was revealed for gray values measured from scans with and without MAR (p = 0.975). CONCLUSIONS The MAR tool in the software of the ORTHOPANTOMOGRAPH OP300 CBCT scanner does not significantly correct the voxel gray values affected by the metal artefact in the vicinity of an implant in human dry mandibles.
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Affiliation(s)
- A Parsa
- 1 Department of General and Specialized Dentistry, Section Oral and Maxillofacial Radiology, Academic Center for Dentistry Amsterdam (ACTA), Amsterdam, Netherlands
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515
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Sancho-Puchades M, Hämmerle CHF, Benic GI. In vitro assessment of artifacts induced by titanium, titanium-zirconium and zirconium dioxide implants in cone-beam computed tomography. Clin Oral Implants Res 2014; 26:1222-8. [PMID: 25040484 DOI: 10.1111/clr.12438] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2014] [Indexed: 11/27/2022]
Abstract
AIM The aim of this study was to test whether or not the intensity of artifacts around implants in cone-beam computed tomography (CBCT) differs between titanium, titanium-zirconium and zirconium dioxide implants. MATERIALS AND METHODS Twenty models of a human mandible, each containing one implant in the single-tooth gap position 45, were cast in dental stone. Five test models were produced for each of the following implant types: titanium 4.1 mm diameter (Ti4.1 ), titanium 3.3 mm diameter (Ti3.3 ), titanium-zirconium 3.3 mm diameter (TiZr3.3 ) and zirconium dioxide 3.5-4.5 mm diameter (ZrO3.5-4.5 ) implants. For control purposes, three models without implants were produced. Each model was scanned using a CBCT device. Gray values (GV) were recorded at eight circumferential positions around the implants at 0.5 mm, 1 mm and 2 mm from the implant surface (GVT est ). GV were assessed in the corresponding volumes of interest (VOI) in the control models without implants (GVC ontrol ). Differences of gray values (ΔGV) between GVT est and GVC ontrol were calculated as percentages. One-way ANOVA and post hoc tests were applied to detect differences between implant types. RESULTS Mean ΔGV for ZrO3.5-4.5 presented the highest absolute values, generally followed by TiZr3.3 , Ti4.1 and Ti3.3 implants. The differences of ΔGV between ZrO3.5-4.5 and the remaining groups were statistically significant in the majority of the VOI (P ≤ 0.0167). ΔGV for TiZr3.3 , Ti4.1 and Ti3.3 implants did not differ significantly in the most VOI. For all implant types, ΔGV showed positive values buccally, mesio-buccally, lingually and disto-lingually, whereas negative values were detected mesially and distally. CONCLUSIONS Zirconium dioxide implants generate significantly more artifacts as compared to titanium and titanium-zirconium implants. The intensity of artifacts around zirconium dioxide implants exhibited in average the threefold in comparison with titanium implants.
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Affiliation(s)
- Manuel Sancho-Puchades
- Clinic for Fixed and Removable Prosthodontics and Material Science, Center for Dental and Oral Medicine and Cranio-Maxillofacial Surgery, University of Zürich, Zürich, Switzerland
| | - Christoph H F Hämmerle
- Clinic for Fixed and Removable Prosthodontics and Material Science, Center for Dental and Oral Medicine and Cranio-Maxillofacial Surgery, University of Zürich, Zürich, Switzerland
| | - Goran I Benic
- Clinic for Fixed and Removable Prosthodontics and Material Science, Center for Dental and Oral Medicine and Cranio-Maxillofacial Surgery, University of Zürich, Zürich, Switzerland
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516
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Kulczyk T, Dyszkiewicz Konwińska M, Owecka M, Krzyżostaniak J, Surdacka A. The influence of amalgam fillings on the detection of approximal caries by cone beam CT: in vitro study. Dentomaxillofac Radiol 2014; 43:20130342. [PMID: 24986630 DOI: 10.1259/dmfr.20130342] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES The aim of this CBCT investigation on the detection of caries was to assess the influence of artefacts produced by the presence of amalgam fillings located in the vicinity. METHODS 102 non-cavitated pre-molar and molar teeth were placed in blocks of silicone with approximal contacts consisting of 3 sound or carious teeth and 1 mesial-occlusal-distal amalgam-filled tooth in-between. Radiographs of all the teeth were recorded using the CBCT system (NewTom™ 3G; QR Srl, Verona, Italy; field of view, 9 inches). Data from the CBCT unit were reconstructed and sectioned in the mesiodistal tooth plane. Images were evaluated twice by two observers, using a five-step confidence scale. After the CBCT examination, the teeth were individually sectioned in the mesiodistal direction with a diamond saw. Using a light microscope at ×40 magnification, the true morphological status of all approximal surfaces was established. RESULTS Sensitivity of the CBCT for the detection of caries on surfaces located proximally and distally to an amalgam filing ranged from 0.27 to 0.30 for enamel and from 0.47 to 0.56 for dentin. Specificity values for enamel proximal and distal lesions were 0.48 and 0.53, respectively, for enamel and 0.33 to 0.38, respectively, for proximal and distal dentin cases. Intra-observer reliability was 0.84, and interobserver reliability was 0.49. CONCLUSIONS Owing to its low specificity, scans from a CBCT examination should not be used to determine the presence of demineralization of the tooth surface when amalgam fillings are present in the region of interest.
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Affiliation(s)
- T Kulczyk
- 1 Department of Biomaterials and Experimental Dentistry, Section of Dental Radiology, Poznan University of Medical Sciences, Poznań, Poland
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517
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Srinivasan K, Mohammadi M, Shepherd J. Applications of linac-mounted kilovoltage Cone-beam Computed Tomography in modern radiation therapy: A review. Pol J Radiol 2014; 79:181-93. [PMID: 25006356 PMCID: PMC4085117 DOI: 10.12659/pjr.890745] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 03/27/2014] [Indexed: 11/23/2022] Open
Abstract
The use of Cone-beam Computed Tomography (CBCT) in radiotherapy is increasing due to the widespread implementation of kilovoltage systems on the currently available linear accelerators. Cone beam CT acts as an effective Image-Guided Radiotherapy (IGRT) tool for the verification of patient position. It also opens up the possibility of real-time re-optimization of treatment plans for Adaptive Radiotherapy (ART). This paper reviews the most prominent applications of CBCT (linac-mounted) in radiation therapy, focusing on CBCT-based planning and dose calculation studies. This is followed by a concise review of the main issues associated with CBCT, such as imaging artifacts, dose and image quality. It explores how medical physicists and oncologists can best apply CBCT for therapeutic applications.
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Affiliation(s)
- Kavitha Srinivasan
- School of Chemistry and Physics, University of Adelaide, Adelaide, Australia
| | - Mohammad Mohammadi
- School of Chemistry and Physics, University of Adelaide, Adelaide, Australia ; Department of Medical Physics, Royal Adelaide Hospital, Adelaide, Australia
| | - Justin Shepherd
- Department of Medical Physics, Royal Adelaide Hospital, Adelaide, Australia
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518
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Abstract
Artifacts in radiographic imaging are discrepancies between the reconstructed visual image and the content of the subject. In radiographic imaging, this means the grayscale values in the image do not accurately reflect the attenuation values of the subject. Structures may also appear that do not exist in the subject. Whatever the source or appearance of image artifacts, their presence degrades the accuracy of the image in relation to the true characteristics of the subject. One should therefore be aware of the presence of artifacts and be familiar with their characteristic appearances in order to enhance the extraction of diagnostic information.
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Affiliation(s)
- Scott R Makins
- Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, MSC 7919, 7703 Floyd Curl Drive, San Antonio, TX 78229-3901, USA.
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519
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Comparing the Image Quality of a Mobile Flat-Panel Computed Tomography and a Multidetector Computed Tomography. Invest Radiol 2014; 49:491-7. [DOI: 10.1097/rli.0000000000000042] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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520
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Ye N, Long H, Xue J, Wang S, Yang X, Lai W. Integration accuracy of laser-scanned dental models into maxillofacial cone beam computed tomography images of different voxel sizes with different segmentation threshold settings. Oral Surg Oral Med Oral Pathol Oral Radiol 2014; 117:780-6. [DOI: 10.1016/j.oooo.2014.02.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 02/05/2014] [Accepted: 02/19/2014] [Indexed: 11/25/2022]
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521
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Kim DG. Can dental cone beam computed tomography assess bone mineral density? J Bone Metab 2014; 21:117-26. [PMID: 25006568 PMCID: PMC4075265 DOI: 10.11005/jbm.2014.21.2.117] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 05/18/2014] [Accepted: 05/18/2014] [Indexed: 12/02/2022] Open
Abstract
Mineral density distribution of bone tissue is altered by active bone modeling and remodeling due to bone complications including bone disease and implantation surgery. Clinical cone beam computed tomography (CBCT) has been examined whether it can assess oral bone mineral density (BMD) in patient. It has been indicated that CBCT has disadvantages of higher noise and lower contrast than conventional medical computed tomography (CT) systems. On the other hand, it has advantages of a relatively lower cost and radiation dose but higher spatial resolution. However, the reliability of CBCT based mineral density measurement has not yet been fully validated. Thus, the objectives of this review are to discuss 1) why assessment of BMD distribution is important and 2) whether the clinical CBCT can be used as a potential tool to measure the BMD. Brief descriptions of image artefacts associated with assessment of gray value, which has been used to account for mineral density, in CBCT images are provided. Techniques to correct local and conversion errors in obtaining the gray values in CBCT images are also introduced. This review can be used as a quick reference for users who may encounter these errors during analysis of CBCT images.
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Affiliation(s)
- Do-Gyoon Kim
- Division of Orthodontics, Ohio State University College of Dentistry, Columbus, OH, USA
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522
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Oliveira ML, Freitas DQ, Ambrosano GMB, Haiter-Neto F. Influence of exposure factors on the variability of CBCT voxel values: a phantom study. Dentomaxillofac Radiol 2014; 43:20140128. [PMID: 24869906 DOI: 10.1259/dmfr.20140128] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To assess the influence of milliamperage and kilovolt peak (kVp) on the variability of cone beam CT (CBCT) voxel values. METHODS CBCT scans were obtained from radiographic phantoms in varying concentrations of dipotassium hydrogen phosphate solutions (200-1200 mg ml(-1)) under different protocols of milliamperage and kVp. In addition, scans were performed with and without a dental implant and exo-mass. The variability of CBCT voxel values was measured on each scan, and factorial analysis of variance and the post hoc Tukey test were performed (α = 0.05). Linear regression was performed to assess the relationship between voxel value variability and dipotassium hydrogen phosphate concentration. RESULTS milliamperage and the presence of a dental implant did not produce significant interference (p = 0.28 and 0.87, respectively) in voxel value variability. Scans at the highest kVp value presented a significant reduction (p ≤ 0.0001) in voxel value variability when only exo-mass was not present. Voxel value variability was not influenced by exo-mass in scans at the highest levels of milliamperage and kVp. The presence of exo-mass produced a significant reduction (p ≤ 0.0001) in voxel value variability in most of the scans. Higher concentrations yielded greater variations in voxel values in all scans, except for those operating at the highest levels of mAs and kVp. CONCLUSIONS mAs did not influence the variability of CBCT voxel values; higher kVp reduced such variability when only the object was smaller than the field of view.
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Affiliation(s)
- M L Oliveira
- Department of Oral Diagnosis, Division of Oral Radiology, State University of Campinas, Piracicaba Dental School, Piracicaba, Sao Paulo, Brazil
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523
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Vijayan S, Reinertsen I, Hofstad EF, Rethy A, Hernes TAN, Langø T. Liver deformation in an animal model due to pneumoperitoneum assessed by a vessel-based deformable registration. MINIM INVASIV THER 2014; 23:279-86. [PMID: 24848136 DOI: 10.3109/13645706.2014.914955] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
PURPOSE Surgical navigation based on preoperative images partly overcomes some of the drawbacks of minimally invasive interventions - reduction of free sight, lack of dexterity and tactile feedback. The usefulness of preoperative images is limited in laparoscopic liver surgery, as the liver shifts due to respiration, induction of pneumoperitoneum and surgical manipulation. In this study, we evaluated the shift and deformation in an animal liver caused by respiration and pneumopertioneum using intraoperative cone beam CT. MATERIAL AND METHODS 3D cone beam CT scans were acquired with arterial contrast. The centerlines of the segmented vessels were extracted from the images taken at different respiration and pressure settings. A non-rigid registration method was used to measure the shift and deformation. The mean Euclidean distance between the annotated landmarks was used for evaluation. RESULTS A shift and deformation of 44.6 mm on average was introduced due to the combined effect of respiration and pneumoperitoneum. On average 91% of the deformations caused by the respiration and pneumoperitoneum were recovered. CONCLUSION The results can contribute to the use of intraoperative imaging to correct for anatomic shift so that preoperative data can be used with greater confidence and accuracy during guidance of laparoscopic liver procedures.
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Affiliation(s)
- Sinara Vijayan
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU) , Trondheim , Norway
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524
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Somogyi-Ganss E, Holmes HI, Jokstad A. Accuracy of a novel prototype dynamic computer-assisted surgery system. Clin Oral Implants Res 2014; 26:882-890. [DOI: 10.1111/clr.12414] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Eszter Somogyi-Ganss
- Discipline of Prosthodontics; Faculty of Dentistry; University of Toronto; Toronto ON Canada
| | - Howard I. Holmes
- Discipline of Oral and Maxillofacial Surgery; Faculty of Dentistry; University of Toronto; Toronto ON Canada
| | - Asbjørn Jokstad
- Discipline of Prosthodontics; Faculty of Dentistry; University of Toronto; Toronto ON Canada
- Faculty of Health Sciences; UiT The Arctic University of Norway; Tromsø Norway
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525
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Ballhausen H, Reiner M, Ganswindt U, Belka C, Söhn M. Post-processing sets of tilted CT volumes as a method for metal artifact reduction. Radiat Oncol 2014; 9:114. [PMID: 24886640 PMCID: PMC4080687 DOI: 10.1186/1748-717x-9-114] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 05/03/2014] [Indexed: 11/22/2022] Open
Abstract
Background Metal implants, surgical clips and other foreign bodies may cause ‘streaking’ or ‘star’ artifacts in computed tomography (CT) reconstructions, for example in the vicinity of dental restorations or hip implants. The deteriorated image quality complicates contouring and has an adverse effect on quantitative planning in external beam therapy. Methods The potential to reduce artifacts by acquisition of tilted CT reconstructions from different angles of the same object was investigated. While each of those reconstructions still contained artifacts, they were not necessarily in the same place in each CT. By combining such CTs with complementary information, a reconstructed volume with less or even without artifacts was obtained. The most straightforward way to combine the co-registered volumes was to calculate the mean or median per voxel. The method was tested with a calibration phantom featuring a titanium insert, and with a human skull featuring multiple dental restorations made from gold and steel. The performance of the method was compared to established metal artifact reduction (MAR) algorithms. Dose reduction was tested. Results In a visual comparison, streaking artifacts were strongly reduced and details in the vicinity of metal foreign bodies became much more visible. In case of the calibration phantom, average bias in Hounsfield units was reduced by 94% and per-voxel-errors and noise were reduced by 83%. In case of the human skull, bias was reduced by 95% and noise was reduced by 94%. The performance of the method was visually superior and quantitatively compareable to established MAR algorithms. Dose reduction was viable. Conclusions A simple post-processing method for MAR was described which required one or more complementary scans but did not rely on any a priori information. The method was computationally inexpensive. Performance of the method was quantitatively comparable to established algorithms and visually superior in a direct comparison. Dose reduction was demonstrated, artifacts could be reduced without compromising total dose to the patient.
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Affiliation(s)
- Hendrik Ballhausen
- Department of Radiotherapy and Radiation Oncology, Ludwig-Maximilians-University of Munich, Marchioninistrasse 15, 81377 Munich, Germany.
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526
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Wenzel A. Radiographic display of carious lesions and cavitation in approximal surfaces: Advantages and drawbacks of conventional and advanced modalities. Acta Odontol Scand 2014; 72:251-64. [PMID: 24512205 DOI: 10.3109/00016357.2014.888757] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Treatment strategies have changed with efforts on arresting carious lesions suspected to have an intact surface sparing operative treatment for cavitated lesions. Radiography is still the most recommended adjunct method in the diagnosis of clinically inaccessible approximal surfaces. BITEWING RADIOGRAPHY: The major drawback of bitewing radiography for caries diagnosis is that the clinical state of the surface cannot be determined; i.e. if cavitation has developed or the demineralized surface is still intact. Based on studies of the relationship between radiographic lesion depth and clinical cavitation in approximal surfaces, a threshold for operative treatment decision has been suggested when a lesion is observed radiographically more than one-third into dentine. However, the results from previous studies are contradictory and the majority of studies are ~25 years old. In addition, there are few longitudinal observational studies on the behaviour of dentinal carious lesions, particularly in adults. CONE BEAM COMPUTED TOMOGRAPHY: Cone beam CT is an advanced 3-dimensional radiographic modality, which seems much more accurate than intra-oral modalities for displaying cavitation in approximal surfaces. Nonetheless, there are several drawbacks with CBCT, such as radiation dose, costs and imaging artefacts. Therefore, CBCT cannot be advocated at current as a primary radiographic examination with the aim of diagnosing cavitated carious lesions. CONCLUSIONS Bitewing radiography is, thus, still state-of-the-art as an adjunct in diagnosing carious lesions in clinically inaccessible approximal surfaces. The risk for cavitation is related to lesion depth, but new studies are needed in both child and adult populations to validate current thresholds for the operative treatment decision based on the radiographic lesion depth.
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Affiliation(s)
- Ann Wenzel
- Oral Radiology, Department of Dentistry, Aarhus University , Denmark
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527
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Wang L, Chen KC, Gao Y, Shi F, Liao S, Li G, Shen SGF, Yan J, Lee PKM, Chow B, Liu NX, Xia JJ, Shen D. Automated bone segmentation from dental CBCT images using patch-based sparse representation and convex optimization. Med Phys 2014; 41:043503. [PMID: 24694160 PMCID: PMC3971832 DOI: 10.1118/1.4868455] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Revised: 01/17/2014] [Accepted: 02/17/2014] [Indexed: 01/18/2023] Open
Abstract
PURPOSE Cone-beam computed tomography (CBCT) is an increasingly utilized imaging modality for the diagnosis and treatment planning of the patients with craniomaxillofacial (CMF) deformities. Accurate segmentation of CBCT image is an essential step to generate three-dimensional (3D) models for the diagnosis and treatment planning of the patients with CMF deformities. However, due to the poor image quality, including very low signal-to-noise ratio and the widespread image artifacts such as noise, beam hardening, and inhomogeneity, it is challenging to segment the CBCT images. In this paper, the authors present a new automatic segmentation method to address these problems. METHODS To segment CBCT images, the authors propose a new method for fully automated CBCT segmentation by using patch-based sparse representation to (1) segment bony structures from the soft tissues and (2) further separate the mandible from the maxilla. Specifically, a region-specific registration strategy is first proposed to warp all the atlases to the current testing subject and then a sparse-based label propagation strategy is employed to estimate a patient-specific atlas from all aligned atlases. Finally, the patient-specific atlas is integrated into a maximum a posteriori probability-based convex segmentation framework for accurate segmentation. RESULTS The proposed method has been evaluated on a dataset with 15 CBCT images. The effectiveness of the proposed region-specific registration strategy and patient-specific atlas has been validated by comparing with the traditional registration strategy and population-based atlas. The experimental results show that the proposed method achieves the best segmentation accuracy by comparison with other state-of-the-art segmentation methods. CONCLUSIONS The authors have proposed a new CBCT segmentation method by using patch-based sparse representation and convex optimization, which can achieve considerably accurate segmentation results in CBCT segmentation based on 15 patients.
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Affiliation(s)
- Li Wang
- Department of Radiology and BRIC, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Ken Chung Chen
- Department of Oral and Maxillofacial Surgery, Houston Methodist Hospital Research Institute, Houston, Texas 77030 and Department of Stomatology, National Cheng Kung University Medical College and Hospital, Tainan, Taiwan 70403
| | - Yaozong Gao
- Department of Radiology and BRIC, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Feng Shi
- Department of Radiology and BRIC, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Shu Liao
- Department of Radiology and BRIC, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Gang Li
- Department of Radiology and BRIC, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Steve G F Shen
- Department of Oral and Craniomaxillofacial Surgery and Science, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University College of Medicine, Shanghai, China 200011
| | - Jin Yan
- Department of Oral and Craniomaxillofacial Surgery and Science, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University College of Medicine, Shanghai, China 200011
| | - Philip K M Lee
- Hong Kong Dental Implant and Maxillofacial Centre, Hong Kong, China 999077
| | - Ben Chow
- Hong Kong Dental Implant and Maxillofacial Centre, Hong Kong, China 999077
| | - Nancy X Liu
- Department of Oral and Maxillofacial Surgery, Houston Methodist Hospital Research Institute, Houston, Texas 77030 and Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China 100050
| | - James J Xia
- Department of Oral and Maxillofacial Surgery, Houston Methodist Hospital Research Institute, Houston, Texas 77030; Department of Surgery (Oral and Maxillofacial Surgery), Weill Medical College, Cornell University, New York, New York 10065; and Department of Oral and Craniomaxillofacial Surgery and Science, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University College of Medicine, Shanghai, China 200011
| | - Dinggang Shen
- Department of Radiology and BRIC, University of North Carolina at Chapel Hill, North Carolina 27599 and Department of Brain and Cognitive Engineering, Korea University, Seoul, South Korea 136701
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528
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Kamburoğlu K, Murat S, Kılıç C, Yüksel S, Avsever H, Farman A, Scarfe WC. Accuracy of CBCT images in the assessment of buccal marginal alveolar peri-implant defects: effect of field of view. Dentomaxillofac Radiol 2014; 43:20130332. [PMID: 24645965 DOI: 10.1259/dmfr.20130332] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To investigate the reliability and accuracy of cone beam CT (CBCT) images obtained at different fields of view in detecting and quantifying simulated buccal marginal alveolar peri-implant defects. METHODS Simulated buccal defects were prepared in 69 implants inserted into cadaver mandibles. CBCT images at three different fields of view were acquired: 40 × 40, 60 × 60 and 100 × 100 mm. The presence or absence of defects was assessed on three sets of images using a five-point scale by three observers. Observers also measured the depth, width and volume of defects on CBCT images, which were compared with physical measurements. The kappa value was calculated to assess intra- and interobserver agreement. Six-way repeated analysis of variance was used to evaluate treatment effects on the diagnosis. Pairwise comparisons of median true-positive and true-negative rates were calculated by the χ² test. Pearson's correlation coefficient was used to determine the relationship between measurements. Significance level was set as p < 0.05. RESULTS All observers had excellent intra-observer agreement. Defect status (p < 0.001) and defect size (p < 0.001) factors were statistically significant. Pairwise interactions were found between defect status and defect size (p = 0.001). No differences between median true-positive or true-negative values were found between CBCT field of views (p > 0.05). Significant correlations were found between physical and CBCT measurements (p < 0.001). CONCLUSIONS All CBCT images performed similarly for the detection of simulated buccal marginal alveolar peri-implant defects. Depth, width and volume measurements of the defects from various CBCT images correlated highly with physical measurements.
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Affiliation(s)
- K Kamburoğlu
- Department of Dentomaxillofacial Radiology, Faculty of Dentistry, Ankara University, Ankara, Turkey
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529
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Plachtovics M, Bujtar P, Nagy K, Mommaerts M. High-quality image acquisition by double exposure overlap in dental cone beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol 2014; 117:760-7. [PMID: 24736110 DOI: 10.1016/j.oooo.2014.02.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 02/11/2014] [Accepted: 02/19/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE With a double exposure overlapping cone beam computed tomography (CBCT) scan technique, using CBCT acquisition radiation dose, the objective was to obtain apparent density similar to that of multidetector computed tomography (MDCT). STUDY DESIGN Factory quality-assurance phantom and water phantom were used for the evaluation of apparent density fidelity of iCAT scans in different modes. Each scan's apparent density was analyzed for identical regions using ImageJ, version 1.42q. RESULTS The iCAT Classic extended height acquisition with 4-cm central overlap and reconstruction of 2 groups of 300 projections per rotation for the water and quality-assurance CBCT phantoms resulted in improved apparent density fidelity. This apparent density accuracy was superior to that of iCAT scan at high resolution (600 projections during 1 rotation). CONCLUSIONS Using double exposure overlapping CBCT scans allows the analysis quality to be comparable with that of MDCT.
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Affiliation(s)
- Mark Plachtovics
- Research Associate, University of Szeged, Faculty of Dentistry, Szeged, Hungary.
| | - Peter Bujtar
- Research Associate, Oral and Maxillo-Facial Surgery Department, University of Oulu, Oulu, Finland
| | - Katalin Nagy
- Professor, Department of Cranio-Maxillo-Facial Surgery, European Face Centre, Vrije Universiteit Brussel, Brussels, Belgium
| | - Maurice Mommaerts
- Professor, University of Szeged, Faculty of Dentistry, Szeged, Hungary
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530
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Spin-Neto R, Matzen LH, Schropp L, Liedke GS, Gotfredsen E, Wenzel A. Radiographic observers' ability to recognize patient movement during cone beam CT. Dentomaxillofac Radiol 2014; 43:20130449. [PMID: 24660954 DOI: 10.1259/dmfr.20130449] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To assess radiographic observers' ability to recognize patient movement during cone beam CT and to decide early termination of the examination. METHODS 100 patients were video-recorded during cone beam CT examination. Patients' videos were cropped twice: fitting the active 20-s examination time or the initial non-radiation 3 s of the examination. x- and y-coordinates of pre-defined points marked on the patient's face were used to define the reference standard for movement in the 20-s videos. A sample of 40 non-moving and 20 moving patients was selected. Eight observers scored the videos. The 3-s videos were scored: 0, the patient did not move; 1, the patient moved and the examination should be terminated. The 20-s videos were scored: 0, the patient did not move; 1, the patient moved. Re-assessment of 15% of the videos provided intra-observer reproducibility. The 20-s videos were compared with the reference standard providing sensitivity and specificity values (movement/non-movement recognition). The scores of the 3-s videos were compared with the scores of the 20-s videos. RESULTS Intra- and interobserver reproducibility ranged from substantial to almost perfect for both videos. The 20-s videos allowed patient movement recognition with a high specificity and a medium to high sensitivity. The 3-s videos allowed early termination of the examination with a small number of incorrect positive scores. The majority of the patients scored as moving in the 20-s videos were detected in the 3-s videos. CONCLUSIONS By observing video recordings, trained observers are able to recognize patient movement during cone beam CT examination with high specificity and to decide an early termination of the examination.
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Affiliation(s)
- R Spin-Neto
- Oral Radiology, Department of Dentistry, Aarhus University, Aarhus, Denmark
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531
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Suomalainen A, Åberg T, Rautio J, Hurmerinta K. Cone beam computed tomography in the assessment of alveolar bone grafting in children with unilateral cleft lip and palate. Eur J Orthod 2014; 36:603-11. [PMID: 24509615 DOI: 10.1093/ejo/cjt105] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVES To quantify the treatment outcome of secondary alveolar bone grafting (SABG) in individuals with unilateral cleft lip and palate using cone beam computed tomography (CBCT) and to reveal needs for improvement in surgical technique. MATERIAL AND METHODS CBCT images taken 6 months after SABG of 35 patients were analysed. Vertical and horizontal bone supports of the grafted bone at three levels of the roots of the adjacent teeth were classified, the height of the nasal floor was compared with the unaffected side, and the inter- and intraexaminer reproducibility of these evaluations was assessed. RESULTS The grafted bone filled the defect in all three vertical measurement levels in 34 per cent. The labiopalatal thickness of the grafted bone was good in at least one-third of the root length in 66 per cent and fair in 34 per cent. Typically, the bone graft was deficient in the apical and palatal direction. Clear asymmetry in the nasal floor was found in 72 per cent. Kappa values indicated excellent agreement for all but one measured parameter. LIMITATIONS This is a preliminary study involving only a limited number of study subjects. CONCLUSIONS Our results showed mainly a good or fair treatment outcome. Deficiency of the bone graft was observed mostly in the apical and palatal areas of the defect. Asymmetry of the nasal floor was observed frequently. Careful insertion of the bone graft towards the palatal and apical direction of the cleft is recommended.
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Affiliation(s)
- Anni Suomalainen
- *Department of Radiology, Helsinki University Central Hospital and University of Helsinki,
| | - Thomas Åberg
- **Department of Orthodontics, Institute of Dentistry, University of Helsinki
| | - Jorma Rautio
- ***Cleft Palate and Craniofacial Centre, Department of Plastic Surgery, Helsinki University Central Hospital, Finland
| | - Kirsti Hurmerinta
- ***Cleft Palate and Craniofacial Centre, Department of Plastic Surgery, Helsinki University Central Hospital, Finland
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532
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Spin-Neto R, Gotfredsen E, Wenzel A. Variation in voxel value distribution and effect of time between exposures in six CBCT units. Dentomaxillofac Radiol 2014; 43:20130376. [PMID: 24678846 DOI: 10.1259/dmfr.20130376] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The aim of this study is to assess the variation in voxel value distribution in volumetric data sets obtained by six cone beam CT (CBCT) units, and the effect of time between exposures. Six CBCT units [Cranex(®) 3D (CRAN; Soredex Oy, Tuusula, Finland), Scanora(®) 3D (SCAN; Soredex Oy), NewTom™ 5G (NEWT; QR Srl, Verona, Italy), Promax(®) Dimax 3 (Planmeca Oy, Helsinki, Finland), i-CAT (Imaging Sciences International, Hatfield, PA) and 3D Accuitomo FPD80 (Morita, Kyoto, Japan)] were tested. Two volumetric data sets of a dry human skull embedded in acrylic were acquired by each CBCT unit in two sessions on separate days. Each session consisted of 20 exposures: 10 acquired with 30 min between exposures and 10 acquired immediately one after the other. CBCT data were exported as digital imaging and communications in medicine (DICOM) files and converted to text files. The text files were re-organized to contain x-, y- and z-position and grey shade for each voxel. The files were merged to contain 1 record per voxel position, including the voxel values from the 20 exposures in a session. For each voxel, subtractions were performed between Data Set 1 and the remaining 19 data sets (1 - 2, 1 - 3, etc) in a session. Means, medians, ranges and standard deviations for grey shade variation in the subtraction data sets were calculated for each unit and session. For all CBCT units, variation in voxel values was observed throughout the 20 exposures. A "fingerprint" for the grey shade variation was observed for CRAN, SCAN and NEWT. For the other units, the variation was (apparently) randomly distributed. Large discrepancies in voxel value distribution are seen in CBCT images. This variation should be considered in studies that assess minute changes in CBCT images.
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Affiliation(s)
- R Spin-Neto
- Section of Oral Radiology, Department of Dentistry, Aarhus University, Aarhus, Denmark
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533
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De Kok IJ, Thalji G, Bryington M, Cooper LF. Radiographic stents: integrating treatment planning and implant placement. Dent Clin North Am 2014; 58:181-192. [PMID: 24286652 DOI: 10.1016/j.cden.2013.09.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The pivotal point in treatment planning for dental implants occurs when the location of bone is viewed radiographically in the context of the planned prosthesis. Radiographic planning for dental implant therapy should be used only after a review of the patient's systemic health, imaging history, oral health, and local oral conditions. The radiological diagnostic and planning procedure for dental implants can only be fully achieved with the use of a well-designed and -constructed radiographic guide. This article reviews several methods for construction of radiographic guides and how they may be utilized for improving implant surgery planning and performance.
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Affiliation(s)
- Ingeborg J De Kok
- Department of Prosthodontics, School of Dentistry, University of North Carolina, 330 Brauer Hall, CB# 7450, Chapel Hill, NC 27599-7450, USA
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534
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Cone-Beam Computed Tomography. Oral Radiol 2014. [DOI: 10.1016/b978-0-323-09633-1.00011-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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535
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Kamburoglu K, Kolsuz E, Murat S, Eren H, Yüksel S, Paksoy CS. Assessment of buccal marginal alveolar peri-implant and periodontal defects using a cone beam CT system with and without the application of metal artefact reduction mode. Dentomaxillofac Radiol 2013; 42:20130176. [PMID: 23956236 DOI: 10.1259/dmfr.20130176] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To investigate the accuracy of cone beam CT (CBCT) images obtained with and without artefact reduction (AR) in detecting simulated buccal peri-implant and buccal periodontal defects. METHODS 42 implants inserted into edentulous mandibles, and 38 teeth present in dry mandibles were used. Simulated buccal peri-implant defects (n = 22) and buccal periodontal defects (n = 22) were prepared. 20 implants and 18 teeth without simulated defects were the control group. Images of the mandibles were obtained using a Planmeca ProMax(®) 3D Max CBCT unit (Planmeca Oy, Helsinki, Finland). Image reconstructions were prepared without and with low, medium and high AR modes. Images were viewed randomly by six observers twice for the presence of defects. Kappa coefficient was calculated. F2_LD_F1 design for non-parametric analysis of longitudinal data was used. Area under curves (AUCs) were calculated for each observer. Significance level was taken as α = 0.05. RESULTS Intraobserver kappa ranged from 0.140 to 0.792 for peri-implant and from 0.189 to 1.0 for periodontal defects. All factors were statistically significant (p < 0.001), except for image mode and implant brand. Pairwise interactions were found between periodontal defects and peri-implant defects (p < 0.001), observers (p < 0.001), observer and image mode (p < 0.001), defect model and observer (p < 0.001) and defect model, image mode and observer (p = 0.04). AUC values ranged from 0.39 to 0.52 for peri-implant and from 0.45 to 0.71 for periodontal defects. Higher AUC values were found for periodontal defects than for peri-implant defects. CONCLUSIONS Buccal peri-implant defects were more difficult to detect than buccal periodontal defects. No difference was found among CBCT images obtained with and without AR modes.
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Affiliation(s)
- K Kamburoglu
- Department of Dentomaxillofacial Radiology, Ankara University, Ankara, Turkey.
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536
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Parsa A, Ibrahim N, Hassan B, van der Stelt P, Wismeijer D. Bone quality evaluation at dental implant site using multislice CT, micro-CT, and cone beam CT. Clin Oral Implants Res 2013; 26:e1-7. [PMID: 24325572 DOI: 10.1111/clr.12315] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2013] [Indexed: 10/25/2022]
Abstract
OBJECTIVES The first purpose of this study was to analyze the correlation between bone volume fraction (BV/TV) and calibrated radiographic bone density Hounsfield units (HU) in human jaws, derived from micro-CT and multislice computed tomography (MSCT), respectively. The second aim was to assess the accuracy of cone beam computed tomography (CBCT) in evaluating trabecular bone density and microstructure using MSCT and micro-CT, respectively, as reference gold standards. MATERIAL AND METHODS Twenty partially edentulous human mandibular cadavers were scanned by three types of CT modalities: MSCT (Philips, Best, the Netherlands), CBCT (3D Accuitomo 170, J Morita, Kyoto, Japan), and micro-CT (SkyScan 1173, Kontich, Belgium). Image analysis was performed using Amira (v4.1, Visage Imaging Inc., Carlsbad, CA, USA), 3Diagnosis (v5.3.1, 3diemme, Cantu, Italy), Geomagic (studio(®) 2012, Morrisville, NC, USA), and CTAn (v1.11, SkyScan). MSCT, CBCT, and micro-CT scans of each mandible were matched to select the exact region of interest (ROI). MSCT HU, micro-CT BV/TV, and CBCT gray value and bone volume fraction of each ROI were derived. Statistical analysis was performed to assess the correlations between corresponding measurement parameters. RESULTS Strong correlations were observed between CBCT and MSCT density (r = 0.89) and between CBCT and micro-CT BV/TV measurements (r = 0.82). Excellent correlation was observed between MSCT HU and micro-CT BV/TV (r = 0.91). However, significant differences were found between all comparisons pairs (P < 0.001) except for mean measurement between CBCT BV/TV and micro-CT BV/TV (P = 0.147). CONCLUSIONS An excellent correlation exists between bone volume fraction and bone density as assessed on micro-CT and MSCT, respectively. This suggests that bone density measurements could be used to estimate bone microstructural parameters. A strong correlation also was found between CBCT gray values and BV/TV and their gold standards, suggesting the potential of this modality in bone quality assessment at implant site.
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Affiliation(s)
- Azin Parsa
- Section of Oral Radiology, Department of General and Specialized Dentistry, Academic Center for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands
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537
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Ibrahim N, Parsa A, Hassan B, van der Stelt P, Aartman IHA, Nambiar P. Influence of object location in different FOVs on trabecular bone microstructure measurements of human mandible: a cone beam CT study. Dentomaxillofac Radiol 2013; 43:20130329. [PMID: 24265395 DOI: 10.1259/dmfr.20130329] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The aim of this study was to assess the influence of different object locations in different fields of view (FOVs) of two cone beam CT (CBCT) systems on trabecular bone microstructure measurements of a human mandible. A block of dry human mandible was scanned at five different locations (centre, left, right, anterior and posterior) using five different FOVs of two CBCT systems (NewTom™ 5G; QR Verona, Verona, Italy and Accuitomo 170; Morita, Kyoto, Japan). Image analysis software (CTAn software v. 1.1; SkyScan, Kontich, Belgium) was used to assess the trabecular bone microstructural parameters (thickness, Tb.Th; spacing, Tb.Sp; number, Tb.N; bone volume density, BV/TV). All measurements were taken twice by one trained observer. Tb.Th, Tb.Sp and Tb.N varied significantly across different FOVs in the NewTom 5G (p < 0.001) and the Accuitomo 170 (p < 0.001). For location, a significant difference was observed only when measuring BV/TV (p = 0.03) using the NewTom 5G. The trabecular bone microstructural measurements obtained from CBCT systems are influenced by the size of FOVs. Not all trabecular bone parameters measured using different CBCT systems are affected when varying the object location within the FOVs.
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Affiliation(s)
- N Ibrahim
- Department of General and Specialized Dentistry, Section of Oral and Maxillofacial Radiology, Academic Center for Dentistry Amsterdam (ACTA), Amsterdam, Netherlands
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538
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Ho JT, Wu J, Huang HL, Chen MYC, Fuh LJ, Hsu JT. Trabecular bone structural parameters evaluated using dental cone-beam computed tomography: cellular synthetic bones. Biomed Eng Online 2013; 12:115. [PMID: 24207062 PMCID: PMC3826852 DOI: 10.1186/1475-925x-12-115] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 11/07/2013] [Indexed: 11/10/2022] Open
Abstract
Objective This study compared the adequacy of dental cone beam computed tomography (CBCT) and micro computed tomography (micro-CT) in evaluating the structural parameters of trabecular bones. Methods The cellular synthetic bones in 4 density groups (Groups 1–4: 0.12, 0.16, 0.20, and 0.32 g/cm3) were used in this study. Each group comprised 8 experimental specimens that were approximately 1 cm3. Dental CBCT and micro-CT scans were conducted on each specimen to obtain independent measurements of the following 4 trabecular bone structural parameters: bone volume fraction (BV/TV), specific bone surface (BS/BV), trabecular thickness (Tb.Th.), and trabecular separation (Tb.Sp.). Wilcoxon signed ranks tests were used to compare the measurement variations between the dental CBCT and micro-CT scans. A Spearman analysis was conducted to calculate the correlation coefficients (r) of the dental CBCT and micro-CT measurements. Results and Conclusion Of the 4 groups, the BV/TV and Tb.Th. measured using dental CBCT were larger compared with those measured using micro-CT. By contrast, the BS/BV measured using dental CBCT was significantly less compared with those measured using micro-CT. Furthermore, in the low-density groups (Groups 1 and 2), the Tb.Sp. measured using dental CBCT was smaller compared with those measured using micro-CT. However, the Tb.Sp. measured using dental CBCT was slightly larger in the high-density groups (Groups 3 and 4) than it was in the low density groups. The correlation coefficients between the BV/TV, BS/BV, Tb.Th., and Tb.Sp. values measured using dental CBCT and micro-CT were 0.9296 (p < .001), 0.8061 (p < .001), 0.9390 (p < .001), and 0.9583 (p < .001), respectively. Although the dental CBCT and micro-CT approaches exhibited high correlations, the absolute values of BV/TV, BS/BV, Tb.Th., Tb.Sp. differed significantly between these measurements. Additional studies must be conducted to evaluate using dental CBCT in clinical practice.
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Affiliation(s)
| | | | | | | | | | - Jui-Ting Hsu
- School of Dentistry, College of Medicine, China Medical University, Taichung 404, Taiwan.
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539
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Jakobson SJM, Westphalen VPD, Silva Neto UX, Fariniuk LF, Schroeder AGD, Carneiro E. The influence of metallic posts in the detection of vertical root fractures using different imaging examinations. Dentomaxillofac Radiol 2013; 43:20130287. [PMID: 24191261 PMCID: PMC3887484 DOI: 10.1259/dmfr.20130287] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 10/24/2013] [Accepted: 10/30/2013] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVES To assess the influence of metallic posts in the detection of simulated vertical root fractures (VRFs) using the following imaging examinations: 2 cone beam CT (CBCT) systems [CBCT1: NewTom(®) 3G (QR Srl, Verona, Italy) and CBCT2: i-CAT Next Generation(®) (Imaging Sciences International, Hatfield, PA)] and film and digital radiographs. Additionally, the influence of the orientation of the fracture line in the detection of VRFs was evaluated. METHODS 100, human, single-rooted endodontically treated premolars were divided into 5 groups (Group 1: with posts and buccolingual VRFs, Group 2: with posts and mesiodistal VRFs, Group 3: without posts and with buccolingual VRFs, Group 4: without posts and with mesiodistal VRFs, and Group 5: with posts and without VRFs). The premolars were placed in human mandibles and imaged using the four examination modalities. The sensitivity and the specificity of each examination in the experimental groups were calculated. The data were analysed using Student's t-test. RESULTS The presence of metallic posts reduced the sensitivity of the CBCT1 system (p = 0.0244). Digital radiographs and the CBCT1 and CBCT2 systems had a higher sensitivity in detecting buccolingual fractures in teeth with posts, whereas film and digital radiographs had a higher sensitivity in detecting buccolingual fractures in teeth without posts (p < 0.05). The CBCT1 examination demonstrated the lowest specificity (p < 0.05). CONCLUSIONS The presence of metallic posts did not influence the sensitivity of most of the examinations, excluding the CBCT1 system. The fracture line orientation may influence VRF detection.
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Affiliation(s)
- S J M Jakobson
- Department of Endodontics, Pontifical Catholic University of Paraná, Brazil
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540
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Ibrahim N, Parsa A, Hassan B, van der Stelt P, Aartman IHA, Wismeijer D. The effect of scan parameters on cone beam CT trabecular bone microstructural measurements of the human mandible. Dentomaxillofac Radiol 2013; 42:20130206. [PMID: 24132024 DOI: 10.1259/dmfr.20130206] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The objective of this study was to investigate the effect of different cone beam CT scan parameters on trabecular bone microstructure measurements. A human mandibular cadaver was scanned using a cone beam CT (3D Accuitomo 170; J.Morita, Kyota, Japan). 20 cone beam CT images were obtained using 5 different fields of view (4×4 cm, 6×6 cm, 8×8 cm, 10×10 cm and 10×5 cm), 2 types of rotation steps (180° and 360°) and 2 scanning resolutions (standard and high). Image analysis software was used to assess the trabecular bone microstructural parameters (number, thickness and spacing). All parameters were measured twice by one trained observer. Intraclass correlation coefficients showed high intraobserver repeatability (intraclass correlation coefficient, 0.95-0.97) in all parameters across all tested scan parameters. Trabecular bone microstructural measurements varied significantly, especially in smaller fields of view (p = 0.001). There was no significant difference in the trabecular parameters when using different resolutions (number, p = 0.988; thickness, p = 0.960; spacing, p = 0.831) and rotation steps (number, p = 1.000; thickness, p = 0.954; spacing, p = 0.759). The scan field of view significantly influences the trabecular bone microstructure measurements. Rotation steps (180° or 360°) and resolution (standard or high) selections are not relevant.
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Affiliation(s)
- N Ibrahim
- Department of General and Specialized Dentistry, Section of Oral and Maxillofacial Radiology, Academic Center for Dentistry Amsterdam (ACTA), Amsterdam, Netherlands
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541
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Parsa A, Ibrahim N, Hassan B, van der Stelt P, Wismeijer D. Influence of object location in cone beam computed tomography (NewTom 5G and 3D Accuitomo 170) on gray value measurements at an implant site. Oral Radiol 2013. [DOI: 10.1007/s11282-013-0157-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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542
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Automated implant segmentation in cone-beam CT using edge detection and particle counting. Int J Comput Assist Radiol Surg 2013; 9:733-43. [DOI: 10.1007/s11548-013-0946-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 09/09/2013] [Indexed: 10/26/2022]
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543
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de-Azevedo-Vaz SL, Alencar PNB, Rovaris K, Campos PSF, Haiter-Neto F. Enhancement cone beam computed tomography filters improve in vitro periimplant dehiscence detection. Oral Surg Oral Med Oral Pathol Oral Radiol 2013; 116:633-9. [PMID: 24018127 DOI: 10.1016/j.oooo.2013.06.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Revised: 06/14/2013] [Accepted: 06/21/2013] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To investigate whether cone beam computed tomography filters would improve periimplant dehiscence detection. STUDY DESIGN A hundred titanium implants were placed in bovine ribs in which defects simulating periimplant dehiscence had previously been created. After images acquisition, three oral radiologists assessed them with and without the following filters: Angio Sharpen high 5 × 5, Shadow, Sharpen 3 × 3, Sharpen Mild, and Smooth. The McNemar test verified the disagreement between all images versus the reference standard and original images versus images with filters; P < .05 was considered statistically significant. RESULTS Dehiscence detection using the original images and the Shadow filter disagreed from the reference standard (P < .05), as well as when using the filters instead of the original images (P < .05). CONCLUSION All the filters tested, with the exception of the Shadow, improved periimplant dehiscence detection. The Sharpen 3 × 3 filter was considered best for this task.
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Affiliation(s)
- Sergio Lins de-Azevedo-Vaz
- Department of Clinical Dentistry, School of Dentistry, Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil.
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544
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Gamba TO, Oliveira ML, Flores IL, Cruz AD, Almeida SM, Haiter-Neto F, Lopes SL. Influence of cone-beam computed tomography image artifacts on the determination of dental arch measurements. Angle Orthod 2013; 84:274-8. [DOI: 10.2319/040313-255.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
ABSTRACT
Objective:
To compare dental plaster model (DPM) and cone-beam computed tomography (CBCT) in the measurement of the dental arches, and investigate whether CBCT image artifacts compromise the reliability of such measurements.
Materials and Methods:
Twenty patients were divided into two groups based on the presence or absence of metallic restorations in the posterior teeth. Both dental arches of the patients were scanned with the CBCT unit i-CAT, and DPMs were obtained. Two examiners obtained eight arch measurements on the CBCT images and DPMs and repeated this procedure 15 days later. The arch measurements of each patient group were compared separately by the Wilcoxon rank sum (Mann-Whitney U) test, with a significance level of 5% (α = .05). Intraclass correlation measured the level of intraobserver agreement.
Results:
Patients with healthy teeth showed no significant difference between all DPM and CBCT arch measurements (P > .05). Patients with metallic restoration showed significant difference between DPM and CBCT for the majority of the arch measurements (P > .05). The two examiners showed excellent intraobserver agreement for both measuring methods with intraclass correlation coefficient higher than 0.95.
Conclusion:
CBCT provided the same accuracy as DPM in the measurement of the dental arches, and was negatively influenced by the presence of image artifacts.
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Affiliation(s)
- Thiago O. Gamba
- PhD Student, Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, São Paulo, SP, Brazil
| | - Matheus L. Oliveira
- Assistant Professor, Department of Oral Diagnosis and Surgery, Araraquara Dental School, São Paulo State University, São Paulo, SP, Brazil
| | - Isadora L. Flores
- PhD Student, Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, São Paulo, SP, Brazil
| | - Adriana D. Cruz
- Adjunct Professor, Department of Specific Formation, Area of Radiology, Dental School of the Fluminense Federal University, Nova Friburgo, RJ, Brazil
| | - Solange M. Almeida
- Associate Professor, Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, São Paulo, SP, Brazil
| | - Francisco Haiter-Neto
- Professor, Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, São Paulo, SP, Brazil
| | - Sérgio L.P.C. Lopes
- Assistant Professor, Department of Oral Diagnosis and Surgery, São José dos Campos Dental School, São Paulo State University, São Paulo, SP, Brazil
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545
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Zhang G, Marshall N, Jacobs R, Liu Q, Bosmans H. Bowtie filtration for dedicated cone beam CT of the head and neck: a simulation study. Br J Radiol 2013; 86:20130002. [PMID: 23728948 PMCID: PMC3745055 DOI: 10.1259/bjr.20130002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 05/17/2013] [Accepted: 05/28/2013] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To investigate the influence of bowtie filtration on dedicated cone beam CT (CBCT) of the head and neck. METHODS A validated hybrid simulation technique was used to model a commercial CBCT system with offset scanning geometry, 90 kV tube potential and 145×75 mm imaging field of view. Three bowtie filters were formulated to produce uniform flux intensity in the projection image of cylindrical objects of diameter 14, 16 and 18 cm. The influence of these simulated filters was compared with the original flat filtration in terms of the output radiation field, the dose delivered to the object, the scatter distribution in projections and the quality of the reconstructed image. RESULTS Compared against flat filtration, dose reduction for the bowtie case, examined as a function of radial distance within a 16-cm-diameter water cylinder, varied from 8.7% at the centre to 53.8% at the periphery. Scatter reduction, quantified using scatter-to-primary ratio in projection images, was up to 37.6% for a 14-cm-diameter cylindrical contrast phantom. Using the supplied routine image reconstruction, bowtie filtration resulted in comparable noise appearance, contrast resolution and artefact pattern for computational anatomical phantoms, with <5% difference in contrast-to-noise ratio. CONCLUSION Bowtie filtration can effectively reduce the dose and scatter in CBCT of the head and neck. For better image quality, corresponding modification to the image pre-processing and reconstruction is needed. ADVANCES IN KNOWLEDGE The hybrid simulation approach can usefully explore the impact of proposed system component and design changes.
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Affiliation(s)
- G Zhang
- Department of Radiology, University Hospitals Leuven, Leuven, Belgium
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546
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Tchorz JP, Poxleitner PJ, Stampf S, Patzelt SBM, Rottke D, Hellwig E, Altenburger MJ. The use of cone beam computed tomography to predetermine root canal lengths in molar teeth: a comparison between two-dimensional and three-dimensional measurements. Clin Oral Investig 2013; 18:1129-1133. [DOI: 10.1007/s00784-013-1064-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 07/17/2013] [Indexed: 11/24/2022]
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547
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Van Dessel J, Huang Y, Depypere M, Rubira-Bullen I, Maes F, Jacobs R. A comparative evaluation of cone beam CT and micro-CT on trabecular bone structures in the human mandible. Dentomaxillofac Radiol 2013; 42:20130145. [PMID: 23833320 DOI: 10.1259/dmfr.20130145] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVES The main purpose of this study was to determine the accuracy of cone beam CT (CBCT) in measuring the trabecular bone microstructure, in comparison with micro-CT. The subobjective was to examine to what extent bone quality assessment is influenced by X-ray tube current and voltage settings as well as soft tissue surrounding the bone. METHODS Eight human mandibular bone samples were scanned using three different clinical exposure protocol within water (W1-3) and without water (NW1-3) by a high-resolution (80 µm) CBCT machine (3D Accuitomo 170(®); Morita, Kyoto, Japan). Subsequently, the samples underwent micro-CT scanning (SkyScan 1174®; SkyScan, Antwerp, Belgium). After image acquisition, similar volumes of interest of the trabecular structures captured with CBCT and micro-CT were aligned with each other. Segmentation was then performed, and the morphometric parameters were quantified within the volumes of interest by CTAn software (CTAnalyser(®); SkyScan, Antwerp, Belgium). Descriptive statistical analyses and multiple comparisons between all protocols were applied in R software. RESULTS High positive Pearson's correlation coefficients were observed between CBCT and micro-CT protocols for all tested morphometric indices except for trabecular thickness. No significant differences were observed between all exposure protocols except for trabecular separation. When examining the soft-tissue effect on trabecular bone structures, no significant differences between NW (1-3) and W (1-3) protocols were observed for all variables. CONCLUSIONS The present study demonstrated the potential of high-resolution CBCT imaging for in vivo applications of quantitative bone morphometry and bone quality assessment. However, the overestimation of morphometric parameters and acquisition settings in CBCT must be taken into account.
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Affiliation(s)
- J Van Dessel
- Department of Oral Health Science, Oral Imaging Center, KU Leuven, Leuven, Belgium
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548
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Ibrahim N, Parsa A, Hassan B, van der Stelt P, Wismeijer D. Diagnostic imaging of trabecular bone microstructure for oral implants: a literature review. Dentomaxillofac Radiol 2013; 42:20120075. [PMID: 23420864 DOI: 10.1259/dmfr.20120075] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Several dental implant studies have reported that radiographic evaluation of bone quality can aid in reducing implant failure. Bone quality is assessed in terms of its quantity, density, trabecular characteristics and cells. Current imaging modalities vary widely in their efficiency in assessing trabecular structures, especially in a clinical setting. Most are very costly, require an extensive scanning procedure coupled with a high radiation dose and are only partially suitable for patient use. This review examines the current literature regarding diagnostic imaging assessment of trabecular microstructure prior to oral implant placement and suggests cone beam CT as a method of choice for evaluating trabecular bone microstructure.
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Affiliation(s)
- N Ibrahim
- Department of General and Specialized Dentistry, Section of Oral Radiology, Academic Center for Dentistry Amsterdam (ACTA), Gustav Mahlerlaan 3004, 1081 LA Amsterdam, Netherlands.
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549
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de-Azevedo-Vaz SL, Vasconcelos KDF, Neves FS, Melo SLS, Campos PSF, Haiter-Neto F. Detection of periimplant fenestration and dehiscence with the use of two scan modes and the smallest voxel sizes of a cone-beam computed tomography device. Oral Surg Oral Med Oral Pathol Oral Radiol 2013; 115:121-7. [PMID: 23217543 DOI: 10.1016/j.oooo.2012.10.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 10/09/2012] [Accepted: 10/15/2012] [Indexed: 12/18/2022]
Abstract
OBJECTIVE To assess the accuracy of cone-beam computed tomography (CBCT) in periimplant fenestration and dehiscence detection, and to determine the effects of 2 voxel sizes and scan modes. STUDY DESIGN One hundred titanium implants were placed in bovine ribs in which periimplant fenestration and dehiscence were simulated. CBCT images were acquired with the use of 3 protocols of the i-CAT NG unit: A) 0.2 mm voxel size half-scan (180°); B) 0.2 mm voxel size full-scan (360°); and C) 0.12 mm voxel size full scan (360°). Receiver operating characteristic curves and diagnostic values were obtained. The Az values were compared with the use of analysis of variance. RESULTS The Az value for dehiscence in protocol A was significantly lower than those of B or C (P < .01). They did not statistically differ for fenestration (P > .05). CONCLUSIONS Protocol B yielded the highest values. The voxel sizes did not affect fenestration and dehiscence detection, and for dehiscence full-scan performed better than half-scan.
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Affiliation(s)
- Sergio Lins de-Azevedo-Vaz
- Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, State University of Campinas, Piracicaba, São Paulo, Brazil.
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550
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Patel S, Brady E, Wilson R, Brown J, Mannocci F. The detection of vertical root fractures in root filled teeth with periapical radiographs and CBCT scans. Int Endod J 2013; 46:1140-52. [DOI: 10.1111/iej.12109] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 02/09/2013] [Indexed: 02/06/2023]
Affiliation(s)
- S. Patel
- Department of Conservative Dentistry; King's College London Dental Institute; London UK
| | - E. Brady
- Department of Conservative Dentistry; King's College London Dental Institute; London UK
| | - R. Wilson
- Department of Periodontology; King's College London Dental Institute; London UK
| | - J. Brown
- Department of Dento-Maxillofacial Imaging; King's College London Dental Institute; London UK
| | - F. Mannocci
- Department of Conservative Dentistry; King's College London Dental Institute; London UK
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