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Yadegari A, Safi Y, Shahbazi S, Yaghoutiazar S, Ghazizadeh Ahsaie M. Assessment of CBCT gray value in different regions-of-interest and fields-of-view compared to Hounsfield unit. Dentomaxillofac Radiol 2023; 52:20230187. [PMID: 37874074 DOI: 10.1259/dmfr.20230187] [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: 10/25/2023] Open
Abstract
OBJECTIVES Different factors can affect the discrepancy between the gray value (GV) measurements obtained from CBCT and the Hounsfield unit (HU) derived from multidetector CT (MDCT), which is considered the gold-standard density scale. This study aimed to explore the impact of region of interest (ROI) location and field of view (FOV) size on the difference between these two scales as a potential source of error. METHODS Three phantoms, each consisting of a water-filled plastic bin containing a dry dentate human skull, were prepared. CBCT scans were conducted using the NewTom VGi evo system, while MDCT scans were performed using Philips system. Three different FOV sizes (8 × 8 cm, 8 × 12 cm, and 12 × 15 cm) were used, and the GVs obtained from eight distinct ROIs were compared with the HUs from the MDCT scans. The ROIs included dental and bony regions within the anterior and posterior areas of both jaws. Statistical analyses were performed using SPSS v. 26. RESULTS The GVs derived from CBCT images were significantly influenced by both ROI location and FOV size (p < 0.05 for both factors). Following the comparison between GVs and HUs, the anterior mandibular bone ROI represented the minimum error, while the posterior mandibular teeth exhibited the maximum error. Moreover, the 8 × 8 cm and 12 × 15 cm FOVs resulted in the lowest and highest degrees of GV error, respectively. CONCLUSIONS The ROI location and the FOV size can significantly affect the GVs obtained from CBCT images. It is not recommended to use the GV scale within the posterior mandibular teeth region due to the potential for error. Additionally, selecting smaller FOV sizes, such as 8 × 8 cm, can provide GVs closer to the gold-standard numbers.
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Affiliation(s)
- Atiye Yadegari
- Department of Pediatric Dentistry, School of Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Yaser Safi
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Soheil Shahbazi
- Dental Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sahar Yaghoutiazar
- Department of Pediatric Dentistry, School of Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mitra Ghazizadeh Ahsaie
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Eguren M, Holguin A, Diaz K, Vidalon J, Linan C, Pacheco-Pereira C, Lagravere Vich MO. Can gray values be converted to Hounsfield units? A systematic review. Dentomaxillofac Radiol 2022; 51:20210140. [PMID: 34148350 PMCID: PMC8693322 DOI: 10.1259/dmfr.20210140] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVES The purpose of this systematic review was to answer the focus question: "Could the gray values (GVs) from CBCT (cone beam computed tomography) be converted to Hounsfield units (HUs) in multidetector computed tomography (MDCT)?" METHODS The included studies try to answer the research question according to the PICO strategy. Studies were gathered by searching several electronic databases and partial grey literature up to January 2021 without language or time restrictions. The methodological assessment of the studies was performed using The Oral Health Assessment Tool (OHAT) for in vitro studies and the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) for in vivo studies. The Grading of Recommendations Assessment, Development and Evaluation (GRADE system) instrument was applied to assess the level of evidence across the studies. RESULTS 2710 articles were obtained in Phase 1, and 623 citations remained after removing duplicates. Only three studies were included in this review using a two-phase selection process and after applying the eligibility criteria. All studies were methodologically acceptable, although in general terms with low risks of bias. There are some included studies with quite low and limited evidence estimations and recommendation forces; evidencing the need for clinical studies with diagnostic capacity to support its use. CONCLUSIONS This systematic review demonstrated that the GVs from CBCT cannot be converted to HUs due to the lack of clinical studies with diagnostic capacity to support its use. However, it is evidenced that three conversion steps (equipment calibration, prediction equation models, and a standard formula (converting GVs to HUs)) are needed to obtain pseudo Hounsfield values instead of only obtaining them from a regression or directly from the software.
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Affiliation(s)
- Marjorie Eguren
- Master in Orthodontic Graduate Program, Faculty of Stomatology, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Anderson Holguin
- Program of Orthodontics, Faculty of Stomatology, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Karla Diaz
- Stomatology Second Specialty, Universidad Privada San Juan Bautista, Lima, Perú
| | - Jose Vidalon
- Department of Stomatology, Faculty of Stomatology, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Carlos Linan
- Department of Orthodontics, Faculty of Stomatology, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Camila Pacheco-Pereira
- University of Alberta, Faculty of Medicine and Dentistry, School of Dentistry, Dental Radiology, 11405-87 Ave, Edmonton, Canada
| | - Manuel Oscar Lagravere Vich
- University of Alberta, Faculty of Medicine and Dentistry, School of Dentistry, Orthodontic Graduate Program, ECHA 5-524, 11405-87 Ave, Edmonton, Canada
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Köseoğlu Seçgin C, Karslıoğlu H, Özemre MÖ, Orhan K. Gray value measurement for the evaluation of local alveolar bone density around impacted maxillary canine teeth using cone beam computed tomography. Med Oral Patol Oral Cir Bucal 2021; 26:e669-e675. [PMID: 34162816 PMCID: PMC8412450 DOI: 10.4317/medoral.24677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 06/07/2021] [Indexed: 11/05/2022] Open
Abstract
Background To investigate whether any relationship between local alveolar bone density and maxillary canine impaction using gray values from cone beam computed tomography. Material and Methods The cone beam computed tomography images of 151 patients were retrospectively evaluated. Maxillary canine was defined as an impacted tooth when root formation was complete and the patient’s age older than 13 or the other side of the maxillary canine has completely erupted. Similarly, complete eruption was defined as the tooth in its expected occlusion and position. Using the cone beam computed tomography software, the region of interest which was 5 mm2 in area, was placed in the trabecular bone on cross sectional cone beam computed tomography images and the gray value measurements were recorded. After measuring the gray values of all the teeth, the images were grouped according to the field of view size. Comparison of the gray values of impacted and non-impacted teeth was made between images with the same field of view size. Results A total of 151 patients, 101 (66.9%) female and 50 (33.1%) male, were included in the study. The mean age of the patients was 24.94 ±13.9. In images with a 40X40 field of view, the gray values of the impacted canine teeth were higher than the gray values of the non-impacted ones and statistically significant difference was found between them (p=0.003). However no statistically significant difference was found between the gray values of impacted and non-impacted canine teeth in 60x60 and 100x50 field of view (p=0.197, p=0.170, respectively). Conclusions We suggest using the smallest field of view size when evaluating bone density using gray values from cone beam computed tomography images and we support the idea that the local increased bone density may influence on impaction. Key words:Cone-beam computed tomography, tooth, impacted, bone density, maxilla, image processing, computer-assisted.
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Affiliation(s)
- C Köseoğlu Seçgin
- Baskent University, Faculty of Dentistry Department of Dentomaxillofacial Radiology Yukarı Bahçelievler Mah. 82. Sokak No: 26 Çankaya, Ankara, Turkey
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Nascimento EHL, Fontenele RC, Lopes PDA, Santaella GM, Vasconcelos KF, de Freitas DQ, Oenning AC, Groppo FC. Development of a model of soft tissue simulation using ballistic gelatin for CBCT acquisitions related to dentomaxillofacial radiology research. Dentomaxillofac Radiol 2020; 50:20200191. [PMID: 32941781 DOI: 10.1259/dmfr.20200191] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVES To present the ballistic gelatin as a new material capable of simulating the soft tissues in cone-beam CT (CBCT) images. METHODS CBCT images of three piglet heads were acquired with their soft tissues intact (standard group). Subsequently, the piglet heads were fixed in a container using metallic pins and moulded with acrylic resin; the soft tissues were then removed and replaced by ballistic gelatin, with the same thickness of the original soft tissues. The images were evaluated by two oral radiologists, to check the adaptation on bone surfaces, thickness and density, penetration into large bone cavities and cancellous bone, and the presence of air bubbles using a 5-score scale. Additionally, an objective analysis was carried out by one oral radiologist. For each CBCT scan, three axial reconstructions were selected to represent the mandibular, occlusal, and maxillary levels. The mean and standard deviation (SD) of the grey values were calculated in four regions of interest determined on soft tissue areas and compared by two-way ANOVA. RESULTS The ballistic gelatin showed subjective scores ranging from good to excellent for all parameters evaluated. There was no significant difference in the mean and SD values of the grey values between ballistic gelatin and the gold standard groups for all levels (p > 0.05). Higher SD values were observed in the occlusal level for both groups (p < 0.05). CONCLUSIONS Ballistic gelatin has visual and objective similarity with the gold standard. Thus, the ballistic gelatin is a promising material capable of simulating soft tissues in CBCT images.
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Affiliation(s)
- Eduarda Helena Leandro Nascimento
- Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, SP, Brazil.,Department of Clinical and Preventive Dentistry, Federal University of Pernambuco (UFPE), Recife, PE, Brazil
| | | | - Priscila de Azeredo Lopes
- Odontoclínica Central da Marinha, Serviço de radiologia e Imaginologia Odontológica, Brazilian Navy, Rio de Janeiro, RJ, Brazil
| | - Gustavo Machado Santaella
- Radiology and Imaging Sciences, Department of Diagnosis and Oral Health, University of Louisville, Lousville, KY, USA
| | - Karla Faria Vasconcelos
- OMFS IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, University of Leuven, University Hospitals Leuven, Leuven, Belgium
| | - Deborah Queiroz de Freitas
- Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, SP, Brazil
| | - Anne Caroline Oenning
- Division of Oral Radiology, Faculdade São Leopoldo Mandic, Instituto de Pesquisas São Leopoldo Mandic, Campinas, Sao Paulo, Brazil
| | - Francisco Carlos Groppo
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, SP, Brazil
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Isman O, Aktan AM, Ertas ET. Evaluating the effects of orthodontic materials, field of view, and artifact reduction mode on accuracy of CBCT-based caries detection. Clin Oral Investig 2019; 24:2487-2496. [PMID: 31811495 DOI: 10.1007/s00784-019-03112-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 10/07/2019] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To investigate the influence of orthodontic materials, field of view (FOV), and artifact reduction (AR) on the assessment of approximal caries using cone beam computed tomography. MATERIALS AND METHODS Forty non-cavitated and restoration-free human premolars and molars ranging from sound to various grades of lesions without cavitations were assigned to 13 groups with different combination of fix appliance equipment. CBCT (cone beam computed tomography) (Planmeca ProMax 3D Mid, Helsinki, Finland) images were obtained using combinations of three orthodontic bracket materials and two orthodontic archwire with small and large FOVs and with and without AR activation. Receiver operating characteristic (ROC) analysis was used to calculate the area under the ROC curve (AUC). RESULTS Interobserver agreement ranged from 0.44 to 0.92 and intraobserver agreement ranged from 0.50 to 0.99. Teeth lacking orthodontic materials had the highest Az values at 0.84. FOV and AR activation did not significantly affect AUC values (P > 0.05). The AUC data were significantly reduced by the addition of stainless steel wire, NT wire, or a combination of a stainless steel bracket with stainless steel wire (P < 0.05). CONCLUSIONS The addition of stainless steel wire, NT wire, or a stainless steel bracket with stainless steel wire combination prevented the diagnosis of non-cavitated interproximal tooth caries by CBCT. With and without AR modes and different FOVs did not influence the diagnosis of interproximal caries lesions with different types of orthodontic equipment. CLINICAL RELEVANCE A wide variety of brackets and wire combinations are used in the clinic; however, the extent to which these combinations impact the diagnosis of caries by CBCT as the effects of FOV and AR algorithms are unknown.
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Affiliation(s)
- Ozlem Isman
- Vocational High School of Health Service, Gaziantep University, 27310, Şehitkamil, Gaziantep, Turkey.
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Shokri A, Ramezani L, Bidgoli M, Akbarzadeh M, Ghazikhanlu-Sani K, Fallahi-Sichani H. Effect of field-of-view size on gray values derived from cone-beam computed tomography compared with the Hounsfield unit values from multidetector computed tomography scans. Imaging Sci Dent 2018; 48:31-39. [PMID: 29581947 PMCID: PMC5863017 DOI: 10.5624/isd.2018.48.1.31] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 01/15/2018] [Accepted: 01/30/2018] [Indexed: 11/18/2022] Open
Abstract
Purpose This study aimed to evaluate the effect of field-of-view (FOV) size on the gray values derived from conebeam computed tomography (CBCT) compared with the Hounsfield unit values from multidetector computed tomography (MDCT) scans as the gold standard. Materials and Methods A radiographic phantom was designed with 4 acrylic cylinders. One cylinder was filled with distilled water, and the other 3 were filled with 3 types of bone substitute: namely, Nanobone, Cenobone, and Cerabone. The phantom was scanned with 2 CBCT systems using 2 different FOV sizes, and 1 MDCT system was used as the gold standard. The mean gray values (MGVs) of each cylinder were calculated in each imaging protocol. Results In both CBCT systems, significant differences were noted in the MGVs of all materials between the 2 FOV sizes (P<.05) except for Cerabone in the Cranex3D system. Significant differences were found in the MGVs of each material compared with the others in both FOV sizes for each CBCT system. No significant difference was seen between the Cranex3D CBCT system and the MDCT system in the MGVs of bone substitutes on images obtained with a small FOV. Conclusion The size of the FOV significantly changed the MGVs of all bone substitutes, except for Cerabone in the Cranex3D system. Both CBCT systems had the ability to distinguish the 3 types of bone substitutes based on a comparison of their MGVs. The Cranex3D CBCT system used with a small FOV had a significant correlation with MDCT results.
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Affiliation(s)
- Abbas Shokri
- Dental Implant Research Center, Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Leila Ramezani
- Dental Implant Research Center, Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mohsen Bidgoli
- Department of Periodontics, Faculty of Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mahdi Akbarzadeh
- Molecular Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Karim Ghazikhanlu-Sani
- Department of Radiology, Faculty of Para Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Hamed Fallahi-Sichani
- Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran
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