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Waungana TH, Qiu K, Tse JJ, Anderson DD, Emery CA, Boyd SK, Manske SL. Accuracy of volumetric bone mineral density measurement in weight bearing, cone beam computed tomography. J Clin Densitom 2024; 27:101504. [PMID: 38897133 DOI: 10.1016/j.jocd.2024.101504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 05/15/2024] [Accepted: 06/03/2024] [Indexed: 06/21/2024]
Abstract
BACKGROUND Weight bearing computed tomography (WBCT) utilizes cone beam CT technology to provide assessments of lower limb joint structures while they are functionally loaded. Grey-scale values indicative of X-ray attenuation that are output from cone beam CT are challenging to calibrate, and their use for bone mineral density (BMD) measurement remains debatable. To determine whether WBCT can be reliably used for cortical and trabecular BMD assessment, we sought to establish the accuracy of BMD measurements at the knee using modern WBCT by comparing them to measurements from conventional CT. METHODS A hydroxyapatite phantom with three inserts of varying densities was used to systematically quantify signal uniformity and BMD accuracy across the acquisition volume. We evaluated BMD in vivo (n = 5, female) using synchronous and asynchronous calibration techniques in WBCT and CT. To account for variation in attenuation along the height (z-axis) of acquisition volumes, we tested a height-dependent calibration approach for both WBCT and CT images. RESULTS Phantom BMD measurement error in WBCT was as high as 15.3% and consistently larger than CT (up to 5.6%). Phantom BMD measures made under synchronous conditions in WBCT improved measurement accuracy by up to 3% but introduced more variability in measured BMD. We found strong correlations (R = 0.96) as well as wide limits of agreement (-324 mgHA/cm3 to 183 mgHA/cm3) from Bland-Altman analysis between WBCT and CT measures in vivo that were not improved by height-dependent calibration. CONCLUSION Whilst BMD accuracy from WBCT was found to be dependent on apparent density, accuracy was independent of the calibration technique (synchronous or asynchronous) and the location of the measurement site within the field of view. Overall, we found strong correlations between BMD measures from WBCT and CT and in vivo measures to be more accurate in trabecular bone regions. Importantly, WBCT can be used to distinguish between anatomically relevant differences in BMD, however future work is necessary to determine the repeatability and sensitivity of BMD measures in WBCT.
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Affiliation(s)
- Tadiwa H Waungana
- Biomedical Engineering Graduate Program, University of Calgary, Alberta, Canada; McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada; Department of Radiology, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Keven Qiu
- McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada; David R. Cheriton School of Computer Science, University of Waterloo, Waterloo, Ontario, Canada
| | - Justin J Tse
- McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada; Department of Radiology, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Donald D Anderson
- Department of Orthopedics and Rehabilitation, University of Iowa, Iowa City, Iowa, United States
| | - Carolyn A Emery
- McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada; Faculty of Kinesiology, University of Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Alberta, Canada; O'Brien Institute for Public Health, University of Calgary, Alberta, Canada
| | - Steven K Boyd
- Biomedical Engineering Graduate Program, University of Calgary, Alberta, Canada; McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada; Department of Radiology, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Sarah L Manske
- Biomedical Engineering Graduate Program, University of Calgary, Alberta, Canada; McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada; Department of Radiology, Cumming School of Medicine, University of Calgary, Alberta, Canada.
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Hu Y, Zhou H, Cao N, Li C, Hu C. Synthetic CT generation based on CBCT using improved vision transformer CycleGAN. Sci Rep 2024; 14:11455. [PMID: 38769329 PMCID: PMC11106312 DOI: 10.1038/s41598-024-61492-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 05/06/2024] [Indexed: 05/22/2024] Open
Abstract
Cone-beam computed tomography (CBCT) is a crucial component of adaptive radiation therapy; however, it frequently encounters challenges such as artifacts and noise, significantly constraining its clinical utility. While CycleGAN is a widely employed method for CT image synthesis, it has notable limitations regarding the inadequate capture of global features. To tackle these challenges, we introduce a refined unsupervised learning model called improved vision transformer CycleGAN (IViT-CycleGAN). Firstly, we integrate a U-net framework that builds upon ViT. Next, we augment the feed-forward neural network by incorporating deep convolutional networks. Lastly, we enhance the stability of the model training process by introducing gradient penalty and integrating an additional loss term into the generator loss. The experiment demonstrates from multiple perspectives that our model-generated synthesizing CT(sCT) has significant advantages compared to other unsupervised learning models, thereby validating the clinical applicability and robustness of our model. In future clinical practice, our model has the potential to assist clinical practitioners in formulating precise radiotherapy plans.
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Affiliation(s)
- Yuxin Hu
- School of Computer and Software, Hohai University, Nanjing, 211100, China
| | - Han Zhou
- School of Electronic Science and Engineering, Nanjing University, NanJing, 210046, China
- Department of Radiation Oncology, The Fourth Affiliated Hospital of Nanjing Medical University, Nanjing, 210013, China
| | - Ning Cao
- School of Computer and Software, Hohai University, Nanjing, 211100, China
| | - Can Li
- Engineering Research Center of TCM Intelligence Health Service, School of Artificial Intelligence and Information Technology, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Can Hu
- School of Computer and Software, Hohai University, Nanjing, 211100, China.
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Schneider M, Schilz JD, Schürer M, Gantz S, Dreyer A, Rothe G, Tillner F, Bodenstein E, Horst F, Beyreuther E. SAPPHIRE -establishment of small animal proton and photon image-guided radiation experiments. Phys Med Biol 2024; 69:095020. [PMID: 38537301 DOI: 10.1088/1361-6560/ad3887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 03/26/2024] [Indexed: 04/25/2024]
Abstract
Thein vivoevolution of radiotherapy necessitates innovative platforms for preclinical investigation, bridging the gap between bench research and clinical applications. Understanding the nuances of radiation response, specifically tailored to proton and photon therapies, is critical for optimizing treatment outcomes. Within this context, preclinicalin vivoexperimental setups incorporating image guidance for both photon and proton therapies are pivotal, enabling the translation of findings from small animal models to clinical settings. TheSAPPHIREproject represents a milestone in this pursuit, presenting the installation of the small animal radiation therapy integrated beamline (SmART+ IB, Precision X-Ray Inc., Madison, Connecticut, USA) designed for preclinical image-guided proton and photon therapy experiments at University Proton Therapy Dresden. Through Monte Carlo simulations, low-dose on-site cone beam computed tomography imaging and quality assurance alignment protocols, the project ensures the safe and precise application of radiation, crucial for replicating clinical scenarios in small animal models. The creation of Hounsfield lookup tables and comprehensive proton and photon beam characterizations within this system enable accurate dose calculations, allowing for targeted and controlled comparison experiments. By integrating these capabilities,SAPPHIREbridges preclinical investigations and potential clinical applications, offering a platform for translational radiobiology research and cancer therapy advancements.
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Affiliation(s)
- Moritz Schneider
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Dresden, Germany
| | - Joshua D Schilz
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Dresden, Germany
| | - Michael Schürer
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- National Center for Tumor Diseases (NCT/UCC), Dresden, Germany: German Cancer Research Center (DKFZ), Heidelberg, Germany; Medizinische Fakultät and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany; Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany
| | - Sebastian Gantz
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, Dresden, Germany
| | - Anne Dreyer
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, Dresden, Germany
| | - Gert Rothe
- Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Falk Tillner
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, Dresden, Germany
- Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Elisabeth Bodenstein
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, Dresden, Germany
| | - Felix Horst
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, Dresden, Germany
| | - Elke Beyreuther
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Dresden, Germany
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He X, Chen Z, Gao Y, Wang W, You M. Reproducibility and location-stability of radiomic features derived from cone-beam computed tomography: a phantom study. Dentomaxillofac Radiol 2023; 52:20230180. [PMID: 37664997 DOI: 10.1259/dmfr.20230180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023] Open
Abstract
OBJECTIVES This study aims to determine the reproducibility and location-stability of cone-beam computed tomography (CBCT) radiomic features. METHODS Centrifugal tubes with six concentrations of K2HPO4 solutions (50, 100, 200, 400, 600, and 800 mg ml-1) were imaged within a customized phantom. For each concentration, images were captured twice as test and retest sets. Totally, 69 radiomic features were extracted by LIFEx. The reproducibility was assessed between the test and retest sets. We used the concordance correlation coefficient (CCC) to screen qualified features and then compared the differences in the numbers of them under 24 series (four locations groups * six concentrations). The location-stability was assessed using the Kruskal-Wallis test under different concentration sets; likewise, the numbers of qualified features under six test sets were analyzed. RESULTS There were 20 and 23 qualified features in the reproducibility and location-stability experiments, respectively. In the reproducibility experiment, the performance of the peripheral groups and high-concentration sets was significantly better than the center groups and low-concentration sets. The effect of concentration on the location-stability of features was not monotonic, and the number of qualified features in the low-concentration sets was greater than that in the high-concentration sets. No features were qualified in both experiments. CONCLUSIONS The density and location of the target object can affect the number of reproducible radiomic features, and its density can also affect the number of location-stable radiomic features. The problem of feature reliability should be treated cautiously in radiomic research on CBCT.
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Affiliation(s)
- Xian He
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, China
| | - Zhi Chen
- School of Communication and Electronic Engineering, East China Normal University, Shanghai, China
| | - Yutao Gao
- School of Computer Science, Sichuan University, Chengdu, China
| | - Wanjing Wang
- Faculty of Mathematics, Sichuan University, Chengdu, China
| | - Meng You
- Department of Oral Medical Imaging, State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Bott KN, Matheson BE, Smith ACJ, Tse JJ, Boyd SK, Manske SL. Addressing Challenges of Opportunistic Computed Tomography Bone Mineral Density Analysis. Diagnostics (Basel) 2023; 13:2572. [PMID: 37568935 PMCID: PMC10416827 DOI: 10.3390/diagnostics13152572] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/20/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
Computed tomography (CT) offers advanced biomedical imaging of the body and is broadly utilized for clinical diagnosis. Traditionally, clinical CT scans have not been used for volumetric bone mineral density (vBMD) assessment; however, computational advances can now leverage clinically obtained CT data for the secondary analysis of bone, known as opportunistic CT analysis. Initial applications focused on using clinically acquired CT scans for secondary osteoporosis screening, but opportunistic CT analysis can also be applied to answer research questions related to vBMD changes in response to various disease states. There are several considerations for opportunistic CT analysis, including scan acquisition, contrast enhancement, the internal calibration technique, and bone segmentation, but there remains no consensus on applying these methods. These factors may influence vBMD measures and therefore the robustness of the opportunistic CT analysis. Further research and standardization efforts are needed to establish a consensus and optimize the application of opportunistic CT analysis for accurate and reliable assessment of vBMD in clinical and research settings. This review summarizes the current state of opportunistic CT analysis, highlighting its potential and addressing the associated challenges.
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Affiliation(s)
- Kirsten N. Bott
- Department of Radiology, University of Calgary, Calgary, AB T2N 1N4, Canada; (K.N.B.); (S.K.B.)
- McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Bryn E. Matheson
- McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB T2N 4Z6, Canada
- Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Ainsley C. J. Smith
- Department of Radiology, University of Calgary, Calgary, AB T2N 1N4, Canada; (K.N.B.); (S.K.B.)
- McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB T2N 4Z6, Canada
- Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Justin J. Tse
- Department of Radiology, University of Calgary, Calgary, AB T2N 1N4, Canada; (K.N.B.); (S.K.B.)
- McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Steven K. Boyd
- Department of Radiology, University of Calgary, Calgary, AB T2N 1N4, Canada; (K.N.B.); (S.K.B.)
- McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Sarah L. Manske
- Department of Radiology, University of Calgary, Calgary, AB T2N 1N4, Canada; (K.N.B.); (S.K.B.)
- McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB T2N 4Z6, Canada
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Sayin H, Aksoy B, Özsoy K. Optimization of CBCT data with image processing methods and production with fused deposition modeling 3D printing. Med Biol Eng Comput 2023:10.1007/s11517-023-02889-w. [PMID: 37505414 DOI: 10.1007/s11517-023-02889-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/13/2023] [Indexed: 07/29/2023]
Abstract
The present study has investigated the effect of the removal of artifacts in cone beam computed tomography (CBCT) images with image processing techniques to dental implant planning. The aim of this study has been to benefit from the novel image processing techniques and additive manufacturing technologies in order to change the existing approach in the usage of the 3D model in the orthogonal surgery, traumatic cases, and tumor operations and to solve the restrictions in surgical operations. In the study, firstly, 3 × 3, 5 × 5, and 7 × 7 kernel values were determined on the CBCT image data of the patient. The determined kernel values were applied on CBCT images by choosing median, median-mean-Gaussian (MMG), and bilateral filters, which are quite successful in removing noise in medical images. A thresholding process to separate teeth and bones from soft tissue regions on CBCT images, histogram normalization for a balanced color distribution, morphology operations to reduce noise areas, and tooth and bone boundaries were determined as closely as possible to patient anatomy. The original image and the images obtained from image enhancement techniques were compared. Results showed that the 3 × 3 median filtering method from three different kernel values out of three different image processing methods used in the study greatly improved the artifacts. It has also been shown that the availability of image processing and additive manufacturing methods on CBCT images has been shown to be a highly important factor before dental surgery planning.
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Affiliation(s)
- Hamdi Sayin
- Department of Mechatronics Engineering, Faculty of Technology, Isparta University of Applied Sciences, Isparta, Turkey
| | - Bekir Aksoy
- Department of Mechatronics Engineering, Faculty of Technology, Isparta University of Applied Sciences, Isparta, Turkey.
| | - Koray Özsoy
- Department of Machine and Metal Technologies, Isparta OSB Vocational School, Isparta University of Applied Sciences, Isparta, Turkey
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Task-Based Image Quality Assessment Comparing Classical and Iterative Cone Beam CT Images on Halcyon ®. Diagnostics (Basel) 2023; 13:diagnostics13030448. [PMID: 36766553 PMCID: PMC9914039 DOI: 10.3390/diagnostics13030448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/10/2023] [Accepted: 01/14/2023] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Despite the development of iterative reconstruction (IR) in diagnostic imaging, CBCT are generally reconstructed with filtered back projection (FBP) in radiotherapy. Varian medical systems, recently released with their latest Halcyon® V2.0 accelerator, a new IR algorithm for CBCT reconstruction. PURPOSE To assess the image quality of radiotherapy CBCT images reconstructed with FBP and an IR algorithm. METHODS Three CBCT acquisition modes (head, thorax and pelvis large) available on a Halcyon® were assessed. Five acquisitions were performed for all modes on an image quality phantom and reconstructed with FBP and IR. Task-based image quality assessment was performed with noise power spectrum (NPS), task-based transfer function (TTF) and detectability index (d'). To illustrate the image quality obtained with both reconstruction types, CBCT acquisitions were made on 6 patients. RESULTS The noise magnitude and the spatial frequency of the NPS peak was lower with IR than with FBP for all modes. For all low and high-contrast inserts, the values for TTF at 50% were higher with IR than with FBP. For all inserts and all modes, the contrast values were similar with FBP and IR. For all low and high-contrast simulated lesions, d' values were higher with IR than with FBP for all modes. These results were also found on the 6 patients where the images were less noisy but smoother with IR-CBCT. CONCLUSIONS Using the IR algorithm for CBCT images in radiotherapy improve image quality and thus could increase the accuracy of online registration and limit positioning errors during processing.
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Zhao R, Wang X, Wei H. Accuracy and Feasibility of Synthetic CT for Lung Adaptive Radiotherapy: A Phantom Study. Technol Cancer Res Treat 2023; 22:15330338231218161. [PMID: 38037343 PMCID: PMC10693223 DOI: 10.1177/15330338231218161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 10/22/2023] [Accepted: 11/14/2023] [Indexed: 12/02/2023] Open
Abstract
OBJECTIVES The respiratory variations will lead to inconsistency between the actual delivery dose and the planning dose. How the minor interfractional amplitude changes affect the geometry and dose delivery accuracy remains to be investigated in the context of lung adaptive radiotherapy. METHODS Planning 4-dimensional-computed tomography and kV-cone beam computed tomography were scanned based on the Computerized Imaging Reference Systems phantom, which was employed to simulate the minor interfractional amplitude variations. The corresponding synthetic computed tomography for a particular motion pattern can be generated from Velocity program. Then a clinically meaningful synthetic computed tomography was analyzed through the geometrical and dosimetric assessment. RESULTS The image quality of synthetic computed tomography was improved obviously compared with cone beam computed tomography. Mean absolute error was minimized when no significant interfractional motion occurs and Velocity can be qualified for dealing with the regular breathing motion patterns. The mean percent hounsfield unit difference of the synthetic hounsfield unit values per organ relative to the planning 4-dimensional-computed tomography image was 22.3%. Under the same conditions, the mean percent hounsfield unit difference of the cone beam computed tomography hounsfield unit values per organ, relative to the planning 4-dimensional-computed tomography image was 83.9%. Overall, the accuracy of hounsfield unit in synthetic computed tomography was improved obviously and the variability of the synthetic image correlates with the planning 4-dimensional-computed tomography image variability. Meanwhile, the dose-volume histograms between planning 4-dimensional-computed tomography and synthetic computed tomography almost coincided each other, which indicates that Velocity program can qualify lung adaptive radiotherapy well when there were no interfractional respiratory variations. However, for cases with obvious interfractional amplitude change, the volume covered at least by 100% of the prescription dose was only 59.6% for that synthetic image. CONCLUSION The synthetic computed tomography images generated from Velocity were close to the real images in anatomy and dosimetry, which can make clinical lung adaptive radiotherapy possible based on the actual patient anatomy during treatment.
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Affiliation(s)
- Ruifeng Zhao
- Department of Radiation Oncology, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xingliu Wang
- Application, Varian Medical System, Beijing, China
| | - Huanhai Wei
- Department of Radiation Oncology, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
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Haase V, Hahn K, Schöndube H, Stierstorfer K, Maier A, Noo F. Single material beam hardening correction via an analytical energy response model for diagnostic CT. Med Phys 2022; 49:5014-5037. [PMID: 35651302 PMCID: PMC9388575 DOI: 10.1002/mp.15787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Various clinical studies show the potential for a wider quantitative role of diagnostic X-ray computed tomography (CT) beyond size measurements. Currently, the clinical use of attenuation values is however limited due to their lack of robustness. This issue can be observed even on the same scanner across patient size and positioning. There are different causes for the lack of robustness in the attenuation values; one possible source of error is beam hardening of the X-ray source spectrum. The conventional and well-established approach to address this issue is a calibration-based single material beam hardening correction (BHC) using a water cylinder. PURPOSE We investigate an alternative approach for single material BHC with the aim of producing a more robust result for the attenuation values. The underlying hypothesis of this investigation is that calibration based BHC automatically corrects for scattered radiation in a manner that is sub-optimal in terms of bias as soon as the scanned object strongly deviates from the water cylinder used for calibration. METHODS The approach we propose performs BHC via an analytical energy response model that is embedded into a correction pipeline that efficiently estimates and subtracts scattered radiation in a patient-specific manner prior to BHC. The estimation of scattered radiation is based on minimizing, in average, the squared difference between our corrected data and the vendor-calibrated data. The used energy response model is considering the spectral effects of the detector response and of the pre-filtration of the source spectrum including a beam-shaping bowtie filter. The performance of the correction pipeline is first characterized with computer simulated data. Afterwards, it is tested using real 3-D CT data sets of two different phantoms, with various kV settings and phantom positions, assuming a circular data acquisition. The results are compared in the image domain to those from the scanner. RESULTS For experiments with a water cylinder, the proposed correction pipeline leads to similar results as the vendor. For reconstructions of a QRM liver phantom with extension ring, the proposed correction pipeline achieved a more uniform and stable outcome in the attenuation values of homogeneous materials within the phantom. For example, the root mean squared deviation between centered and off-centered phantom positioning was reduced from 6.6 HU to 1.8 HU in one profile. CONCLUSIONS We have introduced a patient-specific approach for single material BHC in diagnostic CT via the use of an analytical energy response model. This approach shows promising improvements in terms of robustness of attenuation values for large patient sizes. Our results contribute towards improving CT images so as to make CT attenuation values more reliable for use in clinical practice. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Viktor Haase
- Siemens Healthcare GmbH, Siemensstr. 3, Forchheim, 91301, Germany.,Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstr. 3, Erlangen, 91058, Germany
| | - Katharina Hahn
- Siemens Healthcare GmbH, Siemensstr. 3, Forchheim, 91301, Germany
| | - Harald Schöndube
- Siemens Healthcare GmbH, Siemensstr. 3, Forchheim, 91301, Germany
| | | | - Andreas Maier
- Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstr. 3, Erlangen, 91058, Germany
| | - Frédéric Noo
- Department of Radiology and Imaging Sciences, University of Utah, 729 Arapeen Drive, Salt Lake City, Utah, 84108, USA
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Deng L, Hu J, Wang J, Huang S, Yang X. Synthetic CT generation based on CBCT using respath-cycleGAN. Med Phys 2022; 49:5317-5329. [PMID: 35488299 DOI: 10.1002/mp.15684] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 04/08/2022] [Accepted: 04/13/2022] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Cone-beam computed tomography (CBCT) plays an important role in radiotherapy, but the presence of a large number of artifacts limits its application. The purpose of this study was to use respath-cycleGAN to synthesize CT (sCT) similar to planning CT (pCT) from CBCT for future clinical practice. METHODS The method integrates the respath concept into the original cycleGAN, called respath-cycleGAN, to map CBCT to pCT. Thirty patients were used for training, and 15 for testing. RESULTS The mean absolute error (MAE), root mean square error (RMSE), peak signal to noise ratio (PSNR), structural similarity index (SSIM), and spatial non-uniformity (SNU) were calculated to assess the quality of sCT generated from CBCT. Compared with CBCT images, the MAE improved from 197.72 to 140.7, RMSE from 339.17 to 266.51, and PSNR from 22.07 to 24.44, while SSIM increased from 0.948 to 0.964. Both visually and quantitatively, sCT with respath is superior to sCT without respath. We also performed a generalization test of the head-and-neck (H&N) model on a pelvic dataset. The results again showed that our model was superior. CONCLUSION We developed a respath-cycleGAN method to synthesize CT with good quality from CBCT. In future clinical practice, this method may be used to develop radiotherapy plans. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Liwei Deng
- Heilongjiang Provincial Key Laboratory of Complex Intelligent System and Integration, School of Automation, Harbin University of Science and Technology, Harbin, Heilongjiang, 150080, China
| | - Jie Hu
- School of Automation, Harbin University of Science and Technology, Harbin, Heilongjiang, 150080, China
| | - Jing Wang
- School of Biomedical Engineering, Guangzhou Xinhua University, Guangzhou, Guangdong, 510520, China
| | - Sijuan Huang
- Huang Department of Radiation Oncology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou, Guangdong, 510060, China
| | - Xin Yang
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou, Guangdong, 510060, China
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Gregoris Rabelo LE, Bueno MDR, Costa MVCD, de Musis CR, Estrela CRDA, Guedes OA, Gavini G, Estrela C. Blooming artifact reduction using different cone-beam computed tomography software to analyze endodontically treated teeth with intracanal posts. Comput Biol Med 2021; 136:104679. [DOI: 10.1016/j.compbiomed.2021.104679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 07/20/2021] [Indexed: 10/20/2022]
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Alikhani B, Renne J, Maschke S, Hinrichs JB, Wacker FK, Werncke T. Impact of Patient Alignment on Image Quality in C-Arm Computed Tomography - Evaluation Using an ACR Phantom. ROFO-FORTSCHR RONTG 2020; 193:417-426. [PMID: 32882728 DOI: 10.1055/a-1238-2802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE To evaluate the influence of patient alignment and thereby heel effect on the image quality (IQ) of C-arm flat-panel detector computed tomography (CACT). MATERIALS AND METHODS An ACR phantom placed in opposite directions along the z-axis (setup A and B) on the patient support was imaged using CACT. Image acquisition was performed with three different image acquisition protocols. The images were reconstructed with four convolution kernels. IQ was assessed in terms of high contrast using the modulation transfer function (MTF) and low contrast by assessing the image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratios (CNR) as well as the reliability of density measurements. Furthermore, the dose intensity profiles were measured free-in-air. RESULTS The MTF in setup B is higher than the MTF measured in setup A (p < 0.01). The image noises measured in setup A for the air and bone inserts were higher compared to those measured in setup B (p > 0.05). Opposite behavior has been observed for the polyethylene, water-equivalent and acrylic inserts. The SNR for all inserts is inversely related to the image noise. A systematically increasing or decreasing trend of CNR could not be observed (p > 0.05). The intensity profile measured by the detector system free-in-air showed that the anode heel effect is perpendicular to the z-axis. CONCLUSION The patient alignment has a minor influence on the IQ of CACT. This effect is not based on the X-ray anode heel effect but is caused mainly by the non-symmetrical rotation of CACT. KEY POINTS · The impact of patient alignment and thereby the heel effect on the image quality of CACT was analyzed.. · The patient alignment has a minor influence on the physical parameters related to image quality, such as noise, SNR, and MTF.. · This effect is based mainly on the non-symmetrical rotation of CACT.. CITATION FORMAT · Alikhani B, Renne J, Maschke S et al. Impact of Patient Alignment on Image Quality in C-Arm Computed Tomography - Evaluation Using an ACR Phantom. Fortschr Röntgenstr 2021; 193: 417 - 426.
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Affiliation(s)
- Babak Alikhani
- Center for Radiology and Nuclear Medicine, DIAKOVERE Hospital gGmbH, Hannover, Germany
| | - Julius Renne
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Sabine Maschke
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Jan B Hinrichs
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Frank K Wacker
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Thomas Werncke
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
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Differing trabecular bone architecture in dinosaurs and mammals contribute to stiffness and limits on bone strain. PLoS One 2020; 15:e0237042. [PMID: 32813735 PMCID: PMC7437811 DOI: 10.1371/journal.pone.0237042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/17/2020] [Indexed: 11/19/2022] Open
Abstract
The largest dinosaurs were enormous animals whose body mass placed massive gravitational loads on their skeleton. Previous studies investigated dinosaurian bone strength and biomechanics, but the relationships between dinosaurian trabecular bone architecture and mechanical behavior has not been studied. In this study, trabecular bone samples from the distal femur and proximal tibia of dinosaurs ranging in body mass from 23-8,000 kg were investigated. The trabecular architecture was quantified from micro-computed tomography scans and allometric scaling relationships were used to determine how the trabecular bone architectural indices changed with body mass. Trabecular bone mechanical behavior was investigated by finite element modeling. It was found that dinosaurian trabecular bone volume fraction is positively correlated with body mass similar to what is observed for extant mammalian species, while trabecular spacing, number, and connectivity density in dinosaurs is negatively correlated with body mass, exhibiting opposite behavior from extant mammals. Furthermore, it was found that trabecular bone apparent modulus is positively correlated with body mass in dinosaurian species, while no correlation was observed for mammalian species. Additionally, trabecular bone tensile and compressive principal strains were not correlated with body mass in mammalian or dinosaurian species. Trabecular bone apparent modulus was positively correlated with trabecular spacing in mammals and positively correlated with connectivity density in dinosaurs, but these differential architectural effects on trabecular bone apparent modulus limit average trabecular bone tissue strains to below 3,000 microstrain for estimated high levels of physiological loading in both mammals and dinosaurs.
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Sheng K. Artificial intelligence in radiotherapy: a technological review. Front Med 2020; 14:431-449. [PMID: 32728877 DOI: 10.1007/s11684-020-0761-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Accepted: 02/14/2020] [Indexed: 12/19/2022]
Abstract
Radiation therapy (RT) is widely used to treat cancer. Technological advances in RT have occurred in the past 30 years. These advances, such as three-dimensional image guidance, intensity modulation, and robotics, created challenges and opportunities for the next breakthrough, in which artificial intelligence (AI) will possibly play important roles. AI will replace certain repetitive and labor-intensive tasks and improve the accuracy and consistency of others, particularly those with increased complexity because of technological advances. The improvement in efficiency and consistency is important to manage the increasing cancer patient burden to the society. Furthermore, AI may provide new functionalities that facilitate satisfactory RT. The functionalities include superior images for real-time intervention and adaptive and personalized RT. AI may effectively synthesize and analyze big data for such purposes. This review describes the RT workflow and identifies areas, including imaging, treatment planning, quality assurance, and outcome prediction, that benefit from AI. This review primarily focuses on deep-learning techniques, although conventional machine-learning techniques are also mentioned.
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Affiliation(s)
- Ke Sheng
- Department of Radiation Oncology, University of California, Los Angeles, CA, 90095, USA.
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15
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Mazzi-Chaves JF, de Faria Vasconcelos K, Pauwels R, Jacobs R, Sousa-Neto MD. Cone-beam Computed Tomographic-based Assessment of Filled C-shaped Canals: Artifact Expression of Cone-beam Computed Tomography as Opposed to Micro-computed Tomography and Nano-computed Tomography. J Endod 2020; 46:1702-1711. [PMID: 32682791 DOI: 10.1016/j.joen.2020.07.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/05/2020] [Indexed: 11/30/2022]
Abstract
INTRODUCTION The present study investigated the assessment of root canal fillings in a series of cone-beam computed tomographic (CBCT) images obtained from endodontically treated mandibular molars with C-shaped canals. METHODS Clinically comparable high (HR) and normal (NR) resolution protocols were selected in 3D Accuitomo 170 (J Morita Corporation, Kyoto, Japan), NewTom VGi evo (Cefla QR Verona, Verona, Italy), ProMax 3D Max (Pro; Planmeca, Helsinki, Finland), and Pax-i3D Green Premium (Pax; Vatech, Gyeonggi, South Korea). Micro-computed tomographic and nano-computed tomographic images were considered as the reference standard. The set of images was evaluated according to beam hardening artifact patterns (dark streaks, hypodense areas, and volume distortion). RESULTS Regarding dark streaks, the Fleiss kappa test showed that Pax HR and NR and Pro HR images showed the highest artifact expression. Hypodense areas were detected in 100% and 99.1% of the images obtained using Pax HR and NR, respectively. Kappa tests showed highest distortion for images derived from the Pax and Pro CBCT devices. Root canal filling assessment was considered appropriate in 100% of the 3D Accuitomo 170 HR, NewTom VGi evo NR, micro-computed tomographic, and nano-computed tomographic images. CONCLUSIONS The present study confirms the large variability in CBCT-derived artifact expression. Highlighting the increased artifact expression for particular CBCT systems, it may be concluded that for diagnosis of endodontically filled molars with C-shaped canals, the choice of CBCT unit and protocol is essential.
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Affiliation(s)
- Jardel Francisco Mazzi-Chaves
- Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; Oral and Maxillofacial Surgery, Imaging and Pathology Research Group, Faculty of Medicine, Department of Imaging and Pathology, University of Leuven, University Hospitals Leuven, Leuven, Belgium
| | - Karla de Faria Vasconcelos
- Oral and Maxillofacial Surgery, Imaging and Pathology Research Group, Faculty of Medicine, Department of Imaging and Pathology, University of Leuven, University Hospitals Leuven, Leuven, Belgium
| | - Ruben Pauwels
- Oral and Maxillofacial Surgery, Imaging and Pathology Research Group, Faculty of Medicine, Department of Imaging and Pathology, University of Leuven, University Hospitals Leuven, Leuven, Belgium; Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark; Faculty of Dentistry, Department of Radiology, Chulalongkorn University, Bangkok, Thailand
| | - Reinhilde Jacobs
- Oral and Maxillofacial Surgery, Imaging and Pathology Research Group, Faculty of Medicine, Department of Imaging and Pathology, University of Leuven, University Hospitals Leuven, Leuven, Belgium; Department of Dental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Manoel Damião Sousa-Neto
- Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
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Ghazi P, Hernandez AM, Abbey C, Yang K, Boone JM. Shading artifact correction in breast CT using an interleaved deep learning segmentation and maximum-likelihood polynomial fitting approach. Med Phys 2019; 46:3414-3430. [PMID: 31102462 DOI: 10.1002/mp.13599] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 05/09/2019] [Accepted: 05/12/2019] [Indexed: 12/19/2022] Open
Abstract
PURPOSE The purpose of this work was twofold: (a) To provide a robust and accurate method for image segmentation of dedicated breast CT (bCT) volume data sets, and (b) to improve Hounsfield unit (HU) accuracy in bCT by means of a postprocessing method that uses the segmented images to correct for the low-frequency shading artifacts in reconstructed images. METHODS A sequential and iterative application of image segmentation and low-order polynomial fitting to bCT volume data sets was used in the interleaved correction (IC) method. Image segmentation was performed through a deep convolutional neural network (CNN) with a modified U-Net architecture. A total of 45 621 coronal bCT images from 111 patient volume data sets were segmented (using a previously published segmentation algorithm) and used for neural network training, validation, and testing. All patient data sets were selected from scans performed on four different prototype breast CT systems. The adipose voxels for each patient volume data set, segmented using the proposed CNN, were then fit to a three-dimensional low-order polynomial. The polynomial fit was subsequently used to correct for the shading artifacts introduced by scatter and beam hardening in a method termed "flat fielding." An interleaved utilization of image segmentation and flat fielding was repeated until a convergence criterion was satisfied. Mathematical and physical phantom studies were conducted to evaluate the dependence of the proposed algorithm on breast size and the distribution of fibroglandular tissue. In addition, a subset of patient scans (not used in the CNN training, testing or validation) were used to investigate the accuracy of the IC method across different scanner designs and beam qualities. RESULTS The IC method resulted in an accurate classification of different tissue types with an average Dice similarity coefficient > 95%, precision > 97%, recall > 95%, and F1-score > 96% across all tissue types. The flat fielding correction of bCT images resulted in a significant reduction in either cupping or capping artifacts in both mathematical and physical phantom studies as measured by the integral nonuniformity metric with an average reduction of 71% for cupping and 30% for capping across different phantom sizes, and the Uniformity Index with an average reduction of 53% for cupping and 34% for capping. CONCLUSION The validation studies demonstrated that the IC method improves Hounsfield Units (HU) accuracy and effectively corrects for shading artifacts caused by scatter contamination and beam hardening. The postprocessing approach described herein is relevant to the broad scope of bCT devices and does not require any modification in hardware or existing scan protocols. The trained CNN parameters and network architecture are available for interested users.
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Affiliation(s)
| | - Andrew M Hernandez
- Department of Radiology, University of California Davis, Sacramento, CA, 95817, USA
| | - Craig Abbey
- Department of Psychological & Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Kai Yang
- Department of Radiology, Massachusetts General Hospital, Boston, MA, 2114, USA
| | - John M Boone
- Department of Radiology, University of California Davis, Sacramento, CA, 95817, USA
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Safi Y, Fazlyab M, Asgary S, Fazlalipour M. A Novel Technique for Minimizing the Metal Artifacts on Anterior Teeth in Cone-Beam Computed Tomography. IRANIAN ENDODONTIC JOURNAL 2019; 14:79-83. [PMID: 36879592 PMCID: PMC9984812 DOI: 10.22037/iej.v14i1.21636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/04/2018] [Accepted: 11/19/2018] [Indexed: 03/08/2023]
Abstract
In endodontics, metal artifacts are the major weak points of employing cone-beam computed tomography (CBCT) in teeth with metallic posts and restorations. The aim of this article is to introduce a novel technique for preparation of beneficial CBCT images of anterior teeth with metal posts and/or crowns. In this novel technique, the patient who was instructed to take CBCT images for reason of implant surgery, was asked to puff out his cheeks/lips during the rotation of x-ray tube. By comparing the image taken with this technique to normal image it was obvious that after applying the cheek puffing technique, the metal artifacts around restored anterior teeth significantly reduced. Then it seems that this novel technique removes the metal artifacts from the crowned teeth to distances far from the tooth structure and enables more accurate diagnosis.
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Affiliation(s)
- Yaser Safi
- Department of Radiology, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahta Fazlyab
- Iranian Center for Endodontic Research, Research Institute of Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Endodontics, Faculty of Dentistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Saeed Asgary
- Iranian Center for Endodontic Research, Research Institute of Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maryam Fazlalipour
- Department of Radiology, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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The Effect of Implant-Induced Artifacts on Interpreting Adjacent Bone Structures on Cone-Beam Computed Tomography Scans. IMPLANT DENT 2018; 27:10-14. [PMID: 29095787 DOI: 10.1097/id.0000000000000684] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Cone-beam computed tomography (CBCT) imaging can be used to visualize anatomical structures before implant placement. The aim of this study is to evaluate the impact of implant artifacts on the accuracy of measuring periimplant bone dimensions. MATERIALS AND METHODS Nineteen implants were placed into 9 fresh, frozen cadavers. A CBCT scan was taken, the implants were removed, and a second scan was taken. Implant dimensions and periimplant bone measurements were calculated. The mean differences were compared with paired t tests. Pearson's correlation coefficients were calculated for bone thickness measurements. DISCUSSION No significant differences were found between the implant dimension or bone thickness measurements on each scan. Bone thickness at the implant platform and apex were significantly correlated (P < 0.001). CONCLUSION The presence of dental implants did not impact the accuracy of cone-beam computed tomography (CBCT) measurements of bone thickness by metallic artifacts.
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Elashiry M, Meghil MM, Kalathingal S, Buchanan A, Elrefai R, Looney S, Rajendran M, Ochieng M, Young N, Elawady A, Arce RM, Sandhage KH, Cutler CW. Application of radiopaque micro-particle fillers for 3-D imaging of periodontal pocket analogues using cone beam CT. Dent Mater 2018; 34:619-628. [PMID: 29395473 DOI: 10.1016/j.dental.2018.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 12/07/2017] [Accepted: 01/09/2018] [Indexed: 01/24/2023]
Abstract
BACKGROUND Periodontitis is an infectious/inflammatory disease most often diagnosed by deepening of the gingival sulcus, which leads to periodontal pockets (PPs) conventional manual periodontal probing does not provide detailed information on the three-dimensional (3-D) nature of PPs. OBJECTIVES To determine whether accurate 3-D analyses of the depths and volumes of calibrated PP analogues (PPAs) can be obtained by conventional cone beam computed tomography (CBCT) coupled with novel radiopaque micro-particle fillers (described in the companion paper) injected into the PPAs. METHODS Two PPA models were employed: (1) a human skull model with artificial gingiva applied to teeth with alveolar bone loss and calibrated PPAs, and (2) a pig jaw model with alveolar bone loss and surgically-induced PPAs The PPAs were filled with controlled amounts of radiopaque micro-particle filler using volumetric pipetting Inter-method and intra-method agreement tests were then used to compare the PPA depths and volumes obtained from CBCT images with values obtained by masked examiners using calibrated manual methods. RESULTS Significant inter-method agreement (0.938-0.991) and intra-method agreement (0.94-0.99) were obtained when comparing analog manual data to digital CBCT measurements enabled by the radiopaque filler. SIGNIFICANCE CBCT imaging with radiopaque micro-particle fillers is a plausible means of visualizing and digitally assessing the depths, volumes, and 3-D shapes of PPs This approach could transform the diagnosis and treatment planning of periodontal disease, with particular initial utility in complex cases Efforts to confirm the clinical practicality of these fillers are currently in progress.
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Affiliation(s)
- M Elashiry
- Department of Oral Biology, Augusta University, Augusta, GA, USA; Department of Periodontics, The Dental College of Georgia at Augusta University, Augusta, GA, USA.
| | - M M Meghil
- Department of Oral Biology, Augusta University, Augusta, GA, USA; Department of Periodontics, The Dental College of Georgia at Augusta University, Augusta, GA, USA
| | - S Kalathingal
- Department of Diagnostic Science, The Dental College of Georgia at Augusta University, Augusta, GA, USA
| | - A Buchanan
- Department of Diagnostic Science, The Dental College of Georgia at Augusta University, Augusta, GA, USA
| | - R Elrefai
- Department of Prosthodontics, The Dental College of Georgia at Augusta University, Augusta, GA, USA
| | - S Looney
- Department of Biostatistics, Augusta University, Augusta, GA, USA
| | - M Rajendran
- Department of Periodontics, The Dental College of Georgia at Augusta University, Augusta, GA, USA
| | - M Ochieng
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
| | - N Young
- Department of General Dentistry, Augusta University, Augusta, GA, USA
| | - A Elawady
- Department of Periodontics, The Dental College of Georgia at Augusta University, Augusta, GA, USA
| | - R M Arce
- Department of Periodontics, The Dental College of Georgia at Augusta University, Augusta, GA, USA
| | - K H Sandhage
- School of Materials Engineering, Purdue University, West Lafayette, IN, USA
| | - C W Cutler
- Department of Periodontics, The Dental College of Georgia at Augusta University, Augusta, GA, USA
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Abstract
OBJECTIVE The aim of this study was to investigate the use of one magnetic resonance image-processing tool, FSL, in its ability to perform automated segmentation of computed tomographic images of the brain. METHODS Head computed tomography (CT) images were brain extracted and segmented using the FSL tools BET and FAST, respectively. The products of segmentation were analyzed by histogram. The impact of image intensity inhomogeneity correction was investigated using simulated bias fields, 14 routine head CT scans, and selected illustrative clinical cases. RESULTS FSL FAST performs direct segmentation of head CT images, permitting quantitation of gray and white matter densities and volumes, achieving a more complete segmentation than masking methods. "Bias field correction" reduced the covariance of image signal intensities of the total brain and gray matter images (P < 0.01). Correction is larger when the effects of beam hardening and radiation scatter are larger, resulting in improved segmentation. CONCLUSIONS FSL FAST enables direct segmentation of head CT images.
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Fakhar HB, Emami R, Moloudi K, Mosavat F. Effects of artifact removal on cone-beam computed tomography images. Dent Res J (Isfahan) 2018; 15:89-94. [PMID: 29576771 PMCID: PMC5858077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Dental implants and metal fillings may cause artifacts in cone-beam computed tomography (CBCT) images and reduce image quality and anatomic accuracy. The purposes of this study are a subjective evaluation of anatomic landmarks and linear bone measurements after applying artifact removal (low-medium) option on CBCT images. MATERIALS AND METHODS In this cross-sectional study, thirty CBCT images from thirty qualified patients were selected in a private radiology center. Low and medium artifact removal was applied to images. Three radiologists assessed the visibility of the mandibular canal, mental foramen, and lamina dura in images. Crestal width and bone length were also measured in three groups of images and was compared by exact McNemar test. ICC test (two-way random model, absolute agreement types) was calculated for comparison of linear bone measurements in three images groups. P ≤ 0.05 was considered statistically significant. RESULTS Percent agreement of determining mental foramen (outline and location), mandibular canal (outline and location), and lamina dura between three groups of images were 100%, 100%, 83.3%, 96.7%, and 56.6%, respectively. The results of exact McNemar test revealed that medium artifact removal group had a statistical difference in lamina dura observation with none and low artifact removal groups (P < 0.001). Intraclass correlation coefficient showed no statistical differences in crestal width and bone length between groups (P < 0.001). CONCLUSION Applying artifact removal does not affect the visibility of large anatomical structures and linear bone measurements, but delicate structures such as lamina dura may become less clear after artifact removal.
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Affiliation(s)
- Hooriyeh Bashizade Fakhar
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Raheleh Emami
- Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Semnan University of Medical Sciences, Semnan, Iran,Address for correspondence: Dr. Raheleh Emami, Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Semnan University of Medical Sciences, Semnan, Iran. E-mail:
| | - Kave Moloudi
- Department of Radiology, School of Paramedical Sciences, Iran University of Medical Sciences, Semnan, Iran
| | - Farzaneh Mosavat
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
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Rabelo KA, Cavalcanti YW, de Oliveira Pinto MG, Sousa Melo SL, Campos PSF, de Andrade Freitas Oliveira LS, de Melo DP. Quantitative assessment of image artifacts from root filling materials on CBCT scans made using several exposure parameters. Imaging Sci Dent 2017; 47:189-197. [PMID: 28989902 PMCID: PMC5620464 DOI: 10.5624/isd.2017.47.3.189] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 06/03/2017] [Accepted: 06/07/2017] [Indexed: 02/01/2023] Open
Abstract
Purpose To quantify artifacts from different root filling materials in cone-beam computed tomography (CBCT) images acquired using different exposure parameters. Materials and Methods Fifteen single-rooted teeth were scanned using 8 different exposure protocols with 3 different filling materials and once without filling material as a control group. Artifact quantification was performed by a trained observer who made measurements in the central axial slice of all acquired images in a fixed region of interest using ImageJ. Hyperdense artifacts, hypodense artifacts, and the remaining tooth area were identified, and the percentages of hyperdense and hypodense artifacts, remaining tooth area, and tooth area affected by the artifacts were calculated. Artifacts were analyzed qualitatively by 2 observers using the following scores: absence (0), moderate presence (1), and high presence (2) for hypodense halos, hypodense lines, and hyperdense lines. Two-way ANOVA and the post-hoc Tukey test were used for quantitative and qualitative artifact analysis. The Dunnet test was also used for qualitative analysis. The significance level was set at P<.05. Results There were no significant interactions among the exposure parameters in the quantitative or qualitative analysis. Significant differences were observed among the studied filling materials in all quantitative analyses. In the qualitative analyses, all materials differed from the control group in terms of hypodense and hyperdense lines (P<.05). Fiberglass posts did not differ statistically from the control group in terms of hypodense halos (P>.05). Conclusion Different exposure parameters did not affect the objective or subjective observations of artifacts in CBCT images; however, the filling materials used in endodontic restorations did affect both types of assessments.
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Affiliation(s)
| | | | | | | | | | | | - Daniela Pita de Melo
- Department of Oral Diagnosis, State University of Paraíba, Campina Grande, Brazil
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Abstract
Cone-beam computed tomography (CBCT) has been accepted as a useful tool for diagnosis and treatment planning in dentistry. Despite a growing trend of CBCT in dentistry, it has some disadvantages like artifacts. Artifacts are discrepancies between the reconstructed visual image and the actual content of the subject which degrade the quality of CBCT images, making them diagnostically unusable. Additionally, structures that do not exist in the subject may appear within images. Such structures can occur because of patient motion, the image capture and reconstruction process. To optimize image quality, it is necessary to understand the types of artifacts. This article aims to throw light on the various types of artifacts associated with CBCT images.
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Affiliation(s)
- Anil Kumar Nagarajappa
- Department of Oral Medicine and Radiology, Hitkarini Dental College and Hospital, Jabalpur, Madhya Pradesh, India
| | - Neha Dwivedi
- Department of Oral Medicine and Radiology, Hitkarini Dental College and Hospital, Jabalpur, Madhya Pradesh, India
| | - Rana Tiwari
- Department of Orthodontica and Dentofacial Orthopedics, Hitkarini Dental College and Hospital, Jabalpur, Madhya Pradesh, India
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A Method to Improve Electron Density Measurement of Cone-Beam CT Using Dual Energy Technique. BIOMED RESEARCH INTERNATIONAL 2015; 2015:858907. [PMID: 26346510 PMCID: PMC4540959 DOI: 10.1155/2015/858907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/19/2015] [Accepted: 07/22/2015] [Indexed: 01/24/2023]
Abstract
Purpose. To develop a dual energy imaging method to improve the accuracy of electron density measurement with a cone-beam CT (CBCT) device. Materials and Methods. The imaging system is the XVI CBCT system on Elekta Synergy linac. Projection data were acquired with the high and low energy X-ray, respectively, to set up a basis material decomposition model. Virtual phantom simulation and phantoms experiments were carried out for quantitative evaluation of the method. Phantoms were also scanned twice with the high and low energy X-ray, respectively. The data were decomposed into projections of the two basis material coefficients according to the model set up earlier. The two sets of decomposed projections were used to reconstruct CBCT images of the basis material coefficients. Then, the images of electron densities were calculated with these CBCT images. Results. The difference between the calculated and theoretical values was within 2% and the correlation coefficient of them was about 1.0. The dual energy imaging method obtained more accurate electron density values and reduced the beam hardening artifacts obviously. Conclusion. A novel dual energy CBCT imaging method to calculate the electron densities was developed. It can acquire more accurate values and provide a platform potentially for dose calculation.
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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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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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Schropp L, Wenzel A, Spin-Neto R, Stavropoulos A. Fate of the buccal bone at implants placed early, delayed, or late after tooth extraction analyzed by cone beam CT: 10-year results from a randomized, controlled, clinical study. Clin Oral Implants Res 2014; 26:492-500. [PMID: 24890861 DOI: 10.1111/clr.12424] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2014] [Indexed: 01/03/2023]
Abstract
AIM To present 10-year cone beam CT (CBCT) data on the fate of buccal bone at single-tooth implants placed early, delayed, or late after tooth extraction. MATERIAL AND METHODS Sixty-three of 72 patients, originally randomly allocated to three equal-size groups, received a single-tooth implant on average 10 days (Ea; N = 22), 3 months (De; N = 22), or 1.5 years (La; N = 19) after tooth extraction. Healing abutments were mounted after a 3-month period of submerged healing and metalceramic crowns were cemented after one additional month. At the second stage surgery, presence of buccal bone defects (dehiscences or intrabony) and their dimensions were registered. CBCT scans recorded with a Scanora(®) 3D unit and standardized periapical (PA) radiographs of the implants were obtained at the 10-year control. Interproximal bone levels (i.e., the distance from the implant platform to the first bone-to-implant contact; BIC) measured in CBCT image sections and PA were compared, and the buccal bone level was determined in the CBCT images. RESULTS Two Ea and one De implants failed to osseointegrate. Forty-nine patients attended the 10-year control and due to poor quality of 5 CBCT scans, useful CBCT images were available from 44 patients (Ea:12, De:17, La:15). No significant differences between CBCT and PA images in measurements of the interproximal bone levels were observed. Ten years after implant placement, BIC at the buccal aspect was located on average 2 mm apically to the implant platform (2.39 ± 1.06 mm [median = 2.36] for Ea, 2.22 ± 0.99 mm [median = 2.16] for De, and 1.85 ± 0.65 mm [median = 1.95] for La implants) with no significant difference among the groups (P = 0.20). Mean buccal bone level (bBL) for implants with an intrabony or a dehiscence defect at second stage surgery was 2.51 ± 1.12 mm [median = 2.70] and 2.84 ± 0.70 mm [median = 2.79], respectively, while 1.78 ± 0.74 mm [median = 1.93] for the implants with no defect. The difference in bBL between the implants without a defect and those with a dehiscence was significant at 10 years (P = 0.0005). CONCLUSION Time of placement of single-tooth implants after tooth extraction did not significantly influence the peri-implant buccal bone level, while presence of a buccal bone dehiscence at second stage surgery resulted in significantly more apically located BIC buccally at 10 years.
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Affiliation(s)
- Lars Schropp
- Prosthetic Dentistry, Department of Dentistry, Aarhus University, Aarhus C, Denmark; Oral Radiology, Department of Dentistry, Aarhus University, Aarhus C, Denmark
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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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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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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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Physical quality evaluation of voxel values in cone-beam computed tomography for dental use: three-dimensional fluctuation of voxel values in uniform materials placed inside a phantom. Oral Radiol 2014. [DOI: 10.1007/s11282-014-0169-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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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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Molteni R. Prospects and challenges of rendering tissue density in Hounsfield units for cone beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol 2013; 116:105-19. [DOI: 10.1016/j.oooo.2013.04.013] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 03/11/2013] [Accepted: 04/19/2013] [Indexed: 11/30/2022]
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Artifacts caused by insufficient contrast medium filling during C-arm cone-beam CT scans: a phantom study. Radiol Phys Technol 2013; 7:25-34. [PMID: 23775309 DOI: 10.1007/s12194-013-0227-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/08/2013] [Accepted: 06/10/2013] [Indexed: 10/26/2022]
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Influence of anatomical location on CT numbers in cone beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol 2013; 115:558-64. [DOI: 10.1016/j.oooo.2013.01.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 01/03/2013] [Accepted: 01/22/2013] [Indexed: 11/21/2022]
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36
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Peters CI, Peters OA. Cone beam computed tomography and other imaging techniques in the determination of periapical healing. ACTA ACUST UNITED AC 2013. [DOI: 10.1111/etp.12021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Kim FJ, Sehrt D, Pompeo A, Molina WR. Comparison of surgical plume among laparoscopic ultrasonic dissectors using a real-time digital quantitative technology. Surg Endosc 2012; 26:3408-12. [PMID: 22660839 PMCID: PMC3505554 DOI: 10.1007/s00464-012-2351-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 04/17/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND This study aimed to analyze the effect of surgical plume generation from various ultrasonic dissectors on laparoscopic visibility, including the first cordless ultrasonic dissector, using a novel real-time digital quantification technique. METHODS The Covidien Cordless Sonicision, the Harmonic ACE, and the Olympus SonoSurg were applied to bovine liver with industry-specified settings. Consecutive activations were digitally captured from a laparoscope positioned to replicate the clinical setting. Plume was recognized by ImageJ software, and the percentage of pixels containing plume in each video frame was calculated. Analysis of variance statistical multi-analysis and Welch's t test were computed for all p values. RESULTS The average maximum plume produced by the Sonicision, ACE, and SonoSurg with the maximum setting were respectively 8.76% (range, 4.32-17.41%), 18.04% (range, 9.07-55.12%), and 9.46% (range, 5.68-22.12%) (p = 0.026). The deviations between the ACE and the other devices were significant (p < 0.05). The average maximum plumes produced with the coagulation setting were 4.80% (range, 0.24-19.83%) for the Sonicision, 26.63% (range, 8.12-73.50%) for the ACE, and 0.21% (range, 0.06-1.05%) for the SonoSurg (p < 0.001). The differences between all the instruments in the coagulation setting were significant. CONCLUSION To the authors' knowledge, this is the first report on a real-time digital analysis of surgical plume generation using ImageJ software. In the coagulation setting, the SonoSurg generated minimal plume. The Sonicision obstructed approximately 4%, whereas the ACE generated plume that obstructed 25% of the laparoscopic field. In the cutting setting, the SonoSurg and Sonicision generated the least obstruction, whereas the ACE caused the most obstruction.
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Affiliation(s)
- Fernando J. Kim
- Division of Urology, Denver Health Medical Center, 777 Bannock Street, MC0206, Denver, CO 80204 USA
- Division of Urology, University of Colorado Health Sciences Center, Aurora, CO USA
| | - David Sehrt
- Division of Urology, Denver Health Medical Center, 777 Bannock Street, MC0206, Denver, CO 80204 USA
| | - Alexandre Pompeo
- Division of Urology, Denver Health Medical Center, 777 Bannock Street, MC0206, Denver, CO 80204 USA
| | - Wilson R. Molina
- Division of Urology, Denver Health Medical Center, 777 Bannock Street, MC0206, Denver, CO 80204 USA
- Division of Urology, University of Colorado Health Sciences Center, Aurora, CO USA
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