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Elbashti M, Molinero-Mourelle P, Aswehlee A, Bornstein MM, Abou-Ayash S, Schimmel M, Ella B, Naveau A. Effect of triangular mesh resolution on the geometrical trueness of segmented CBCT maxillofacial data into STL format. J Dent 2023; 138:104722. [PMID: 37742810 DOI: 10.1016/j.jdent.2023.104722] [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: 08/27/2022] [Revised: 08/28/2023] [Accepted: 09/21/2023] [Indexed: 09/26/2023] Open
Abstract
OBJECTIVES To determine the optimal level of mesh reduction that would maintain acceptable levels of geometrical trueness while also minimizing the impact on other parameters such as file size and processing time. METHODS Intraoral and extraoral maxillofacial defects were created on 8 cadaver heads and scanned by using a CBCT scanner (NewTom 3D Imaging, Verona). DICOM data were segmented to produce head (n=8) and skull models (n=8) saved as standard tessellation language (STL) files. A further processing of head models was preformed to produce face (n=8) and ear models (n=8). A mesh reduction process was performed for each STL model (reference, R0) by generating 50% (R1), 75% (R2), and 90% (R3) reductions. The 3 datasets were compared to the R0 file using 3D evaluation software (GOM Inspect) using a global best-fit algorithm, to calculate the root mean square (RMS) deviations. Statistical analyses were performed at a level of significance of α=0.05. RESULTS There was no 3D deviation after the 50% triangular mesh reduction in the 4 datasets. Minor 3D deviations were observed after 75% reduction, in all groups. After 90% reduction, higher 3D deviations were observed, and especially in head and skull. Statistically significant increase in 3D deviations was observed with higher degrees of mesh reduction (p < 0.001). CONCLUSION The resolution of CBCT-based maxillofacial defect models can be reduced up to 50%, with neglectable concern to inaccuracy. CLINICAL SIGNIFICANCE Accurate maxillofacial models can be obtained from CBCT DICOM files after segmentation and export as STL files, even when the mesh resolution is reduced up to 50%. This information can be valuable for practitioners and researchers working with 3D models of maxillofacial defects.
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Affiliation(s)
- Mahmoud Elbashti
- Department of Maxillofacial Prosthetics, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Tokyo, Japan.
| | - Pedro Molinero-Mourelle
- Department of Conservative Dentistry and Orofacial Prosthodontics, Complutense University of Madrid, Madrid, Spain; Department of Reconstructive Dentistry and Gerodontology, University of Bern, Bern, Switzerland.
| | - Amel Aswehlee
- Department of Dental Technology, University of Tripoli, Tripoli, Libya.
| | - Michael M Bornstein
- Department of Oral Health & Medicine, University Center for Dental Medicine Basel UZB, University of Basel, Basel, Switzerland.
| | - Samir Abou-Ayash
- Department of Reconstructive Dentistry and Gerodontology, University of Bern, Bern, Switzerland.
| | - Martin Schimmel
- Department of Reconstructive Dentistry and Gerodontology, University of Bern, Bern, Switzerland, and Division of Gerodontology and Removable Prosthodontics, University Clinics of Dental Medicine, University of Geneva, Switzerland.
| | - Bruno Ella
- Oral Surgery Department, School of Surgery, Bordeaux University Hospital, Bordeaux, France.
| | - Adrien Naveau
- Department of Prosthodontics, University of Bordeaux, Bordeaux, France.
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Thuma TBT, Bogovic JA, Gunton KB, Jimenez H, Negreiros B, Pulido JS. The big warp: Registration of disparate retinal imaging modalities and an example overlay of ultrawide-field photos and en-face OCTA images. PLoS One 2023; 18:e0284905. [PMID: 37098039 PMCID: PMC10129009 DOI: 10.1371/journal.pone.0284905] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 04/03/2023] [Indexed: 04/26/2023] Open
Abstract
PURPOSE To develop an algorithm and scripts to combine disparate multimodal imaging modalities and show its use by overlaying en-face optical coherence tomography angiography (OCTA) images and Optos ultra-widefield (UWF) retinal images using the Fiji (ImageJ) plugin BigWarp. METHODS Optos UWF images and Heidelberg en-face OCTA images were collected from various patients as part of their routine care. En-face OCTA images were generated and ten (10) images at varying retinal depths were exported. The Fiji plugin BigWarp was used to transform the Optos UWF image onto the en-face OCTA image using matching reference points in the retinal vasculature surrounding the macula. The images were then overlayed and stacked to create a series of ten combined Optos UWF and en-face OCTA images of increasing retinal depths. The first algorithm was modified to include two scripts that automatically aligned all the en-face OCTA images. RESULTS The Optos UWF image could easily be transformed to the en-face OCTA images using BigWarp with common vessel branch point landmarks in the vasculature. The resulting warped Optos image was then successfully superimposed onto the ten Optos UWF images. The scripts more easily allowed for automatic overlay of the images. CONCLUSIONS Optos UWF images can be successfully superimposed onto en-face OCTA images using freely available software that has been applied to ocular use. This synthesis of multimodal imaging may increase their potential diagnostic value. Script A is publicly available at https://doi.org/10.6084/m9.figshare.16879591.v1 and Script B is available at https://doi.org/10.6084/m9.figshare.17330048.
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Affiliation(s)
- Tobin B T Thuma
- Department of Pediatric Ophthalmology and Strabismus, Wills Eye Hospital, Philadelphia, Pennsylvania, United States of America
| | - John A Bogovic
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Kammi B Gunton
- Department of Pediatric Ophthalmology and Strabismus, Wills Eye Hospital, Philadelphia, Pennsylvania, United States of America
| | - Hiram Jimenez
- Vickie and Jack Farber Vision Research Center, Wills Eye Hospital, Philadelphia, Pennsylvania, United States of America
| | | | - Jose S Pulido
- Vickie and Jack Farber Vision Research Center, Wills Eye Hospital, Philadelphia, Pennsylvania, United States of America
- Retina Service, Wills Eye Hospital, Philadelphia, Pennsylvania, United States of America
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Miranda-Viana M, Fontenele RC, Farias Gomes A, Nogueira-Reis F, Nejaim Y, Oliveira ML, Freitas DQ. Digital file format does not influence the radiographic diagnosis of vertical root fracture. Oral Radiol 2022; 38:452-458. [PMID: 34626307 PMCID: PMC8501329 DOI: 10.1007/s11282-021-00573-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 09/28/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluate the influence of the file format of digital periapical radiographs on the diagnosis of vertical root fracture (VRF). STUDY DESIGN Periapical radiographic images of 34 single-rooted teeth-19 with VRF, and 15 without VRF were acquired using two digital systems-Digora Toto, and Digora Optime, and exported into four different file formats-TIFF, BMP, PNG, and JPEG, totaling 272 radiographs. The radiographs were assessed by five examiners for the detection of VRF, using a 5-point scale (1-definitely absent; 2-probably absent; 3-uncertain; 4-probably present; 5-definitely present). Diagnostic values of area under the ROC curve, specificity, and sensitivity for the diagnosis of VRF were calculated. The results were compared by two-way Analysis of Variance with post hoc Tukey's test. The intra- and inter-examiner agreements were measured by the Kappa test. The significance level was set at 5% for all analyses. RESULTS The values of intra-examiner agreement varied from moderate (0.56) to almost perfect (0.81), while the values of inter-examiner agreement varied from fair (0.29) to moderate (0.60). The image file format did not influence the diagnostic values for VRF for any of the radiographic systems tested (p > 0.05). Digora Toto had significantly greater values of area under the ROC curve than Digora Optime for all file formats (p = 0.001). CONCLUSION The image file format of periapical radiographs does not influence the diagnosis of VRF, regardless of the digital radiography system.
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Affiliation(s)
- Murilo Miranda-Viana
- Oral Radiology Area, Piracicaba Dental School, University of Campinas, Avenida Limeira, 901, Piracicaba, São Paulo, 13414-903, Brazil
| | - Rocharles Cavalcante Fontenele
- Oral Radiology Area, Piracicaba Dental School, University of Campinas, Avenida Limeira, 901, Piracicaba, São Paulo, 13414-903, Brazil.
| | - Amanda Farias Gomes
- Oral Radiology Area, Piracicaba Dental School, University of Campinas, Avenida Limeira, 901, Piracicaba, São Paulo, 13414-903, Brazil
| | - Fernanda Nogueira-Reis
- Oral Radiology Area, Piracicaba Dental School, University of Campinas, Avenida Limeira, 901, Piracicaba, São Paulo, 13414-903, Brazil
| | - Yuri Nejaim
- Oral Radiology Area, Dental School, Federal University of Mato Grosso do Sul, Campo Grande, MS, Brazil
| | - Matheus L Oliveira
- Oral Radiology Area, Piracicaba Dental School, University of Campinas, Avenida Limeira, 901, Piracicaba, São Paulo, 13414-903, Brazil
| | - Deborah Queiroz Freitas
- Oral Radiology Area, Piracicaba Dental School, University of Campinas, Avenida Limeira, 901, Piracicaba, São Paulo, 13414-903, Brazil
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Miranda-Viana M, Madlum DV, Oliveira-Santos N, Gaêta-Araujo H, Haiter-Neto F, Oliveira ML. Influence of the image file format of digital periapical radiographs on the diagnosis of external and internal root resorptions. Clin Oral Investig 2021; 25:4941-4948. [PMID: 33495894 DOI: 10.1007/s00784-021-03803-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/19/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To evaluate the influence of different image file formats of digital radiographic images on the diagnosis of external (ERR) and internal root resorption (IRR). MATERIALS AND METHODS Thirty-four human teeth were selected. For ERR, 20 teeth were used (10 control and 10 with simulated ERR), and for IRR, 14 teeth were used (before and after IRR simulation). Digital periapical radiographs were acquired using the Digora Toto system and exported in four different image file formats: TIFF, BMP, PNG, and JPEG, totaling 192 radiographs. Five examiners evaluated the images using the JPEGView software and scored the detection of ERR or IRR on a 5-point scale. Sensitivity, specificity, accuracy, and the area under the ROC curve were obtained for the diagnosis of ERR and IRR in the different image file formats. Two-way ANOVA compared the diagnostic values between the file formats and the Kappa test assessed intra- and inter-examiner agreement. The significance level was set at 5% (α = 0.05). RESULTS The mean values of intra-examiner agreement were substantial (0.740) for ERR and almost perfect (0.836) for IRR and, inter-examiner was fair (0.263) and moderate (0.421), respectively. No statistically significant differences were found among the different file formats for the diagnostic values of ERR and IRR. CONCLUSION The file format of digital radiographs does not influence the diagnosis of ERR and IRR. CLINICAL RELEVANCE Digital radiographic images may be susceptible to computational factors; however, they can be stored in multiple file formats without affecting the diagnosis of dental root resorptions.
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Affiliation(s)
- Murilo Miranda-Viana
- Piracicaba Dental School, Department of Oral Diagnosis, University of Campinas, Avenida Limeira, 901, São Paulo, 13414-903, Piracicaba, Brazil.
| | - Daniela Verardi Madlum
- Piracicaba Dental School, Department of Oral Diagnosis, University of Campinas, Avenida Limeira, 901, São Paulo, 13414-903, Piracicaba, Brazil
| | - Nicolly Oliveira-Santos
- Piracicaba Dental School, Department of Oral Diagnosis, University of Campinas, Avenida Limeira, 901, São Paulo, 13414-903, Piracicaba, Brazil
| | - Hugo Gaêta-Araujo
- Piracicaba Dental School, Department of Oral Diagnosis, University of Campinas, Avenida Limeira, 901, São Paulo, 13414-903, Piracicaba, Brazil
| | - Francisco Haiter-Neto
- Piracicaba Dental School, Department of Oral Diagnosis, University of Campinas, Avenida Limeira, 901, São Paulo, 13414-903, Piracicaba, Brazil
| | - Matheus L Oliveira
- Piracicaba Dental School, Department of Oral Diagnosis, University of Campinas, Avenida Limeira, 901, São Paulo, 13414-903, Piracicaba, Brazil
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Madlum DV, Gaêta-Araujo H, Brasil DM, Lima CAS, Oliveira ML, Haiter-Neto F. Influence of the file format and transmission app on the radiographic diagnosis of caries lesions. Oral Surg Oral Med Oral Pathol Oral Radiol 2021; 132:448-455. [PMID: 33386287 DOI: 10.1016/j.oooo.2020.11.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/17/2020] [Accepted: 11/29/2020] [Indexed: 10/22/2022]
Abstract
OBJECTIVES This in vitro study aimed to evaluate the influence of the radiographic image file format and the transmission application (app) on the diagnosis of proximal caries lesions. STUDY DESIGN Twenty bitewing radiographs of 40 posterior human teeth placed in phantoms were acquired using the Digora Toto digital sensor. All images were exported as TIFF (Tagged Image File Format), BMP (Windows Bitmap), PNG (Portable Network Graphics), and JPEG (Joint Photographic Experts Group) and transmitted online via WhatsApp and Messenger. Five examiners evaluated the radiographs with no online transmission and as transmitted through the 2 apps for the presence of proximal caries lesions using a 5-point scale. The reference standard for caries lesions was established using micro-computed tomography. Two-way analysis of variance compared values of sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (α = .05). The kappa test was used to assess intra- and interexaminer agreement. RESULTS Sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve values showed no significant differences in the diagnosis of proximal caries lesions between the different image file formats (P ≥ .773) and transmission apps (P ≥ .608). Intraexaminer agreement was substantial (κ = 0.742) and interexaminer agreement was moderate (κ = 0.475). CONCLUSION The digital file format and transmission app did not influence the radiographic diagnosis of proximal caries lesions.
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Affiliation(s)
- Daniela Verardi Madlum
- Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil.
| | - Hugo Gaêta-Araujo
- Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil
| | - Danieli Moura Brasil
- Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil
| | - Carlos Augusto Souza Lima
- Faculdade São Leopoldo Mandic, Instituto de Pesquisas São Leopoldo Mandic, Division of Oral Radiology, Campinas, Brazil
| | - Matheus L Oliveira
- Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil
| | - Francisco Haiter-Neto
- Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil
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Reproducibility of cephalometric landmarks on posteroanterior digital radiographs using DICOM and JPEG formats. Oral Radiol 2015. [DOI: 10.1007/s11282-015-0217-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Flint AC. Determining optimal medical image compression: psychometric and image distortion analysis. BMC Med Imaging 2012; 12:24. [PMID: 22849336 PMCID: PMC3431233 DOI: 10.1186/1471-2342-12-24] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 07/17/2012] [Indexed: 11/26/2022] Open
Abstract
Background Storage issues and bandwidth over networks have led to a need to optimally compress medical imaging files while leaving clinical image quality uncompromised. Methods To determine the range of clinically acceptable medical image compression across multiple modalities (CT, MR, and XR), we performed psychometric analysis of image distortion thresholds using physician readers and also performed subtraction analysis of medical image distortion by varying degrees of compression. Results When physician readers were asked to determine the threshold of compression beyond which images were clinically compromised, the mean image distortion threshold was a JPEG Q value of 23.1 ± 7.0. In Receiver-Operator Characteristics (ROC) plot analysis, compressed images could not be reliably distinguished from original images at any compression level between Q = 50 and Q = 95. Below this range, some readers were able to discriminate the compressed and original images, but high sensitivity and specificity for this discrimination was only encountered at the lowest JPEG Q value tested (Q = 5). Analysis of directly measured magnitude of image distortion from subtracted image pairs showed that the relationship between JPEG Q value and degree of image distortion underwent an upward inflection in the region of the two thresholds determined psychometrically (approximately Q = 25 to Q = 50), with 75 % of the image distortion occurring between Q = 50 and Q = 1. Conclusion It is possible to apply lossy JPEG compression to medical images without compromise of clinical image quality. Modest degrees of compression, with a JPEG Q value of 50 or higher (corresponding approximately to a compression ratio of 15:1 or less), can be applied to medical images while leaving the images indistinguishable from the original.
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Baksi BG, Fidler A. Fractal analysis of periapical bone from lossy compressed radiographs: a comparison of two lossy compression methods. J Digit Imaging 2012; 24:993-8. [PMID: 21465294 DOI: 10.1007/s10278-011-9383-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The aim of the study was to evaluate the effect of two lossy image compression methods on fractal dimension (FD) calculation. Ten periapical images of the posterior teeth with no restorations or previous root canal therapy were obtained using storage phosphor plates and were saved in TIF format. Then, all images were compressed with lossy JPEG and JPEG2000 compression methods at five compression levels, i.e., 90, 70, 50, 30, and 10. Compressed file sizes from all images and compression ratios were calculated. On each image, two regions of interest (ROIs) containing healthy trabecular bone in the posterior periapical area were selected. The FD of each ROI on the original and compressed images was calculated using differential box counting method. Both image compression and analysis were performed by a public domain software. Altogether, the FD of 220 ROIs was calculated. FDs were compared using ANOVA and Dunnett tests. The FD decreased gradually with compression level. A statistically significant decrease of the FD values was found for JPEG 10, JPEG2000 10, and JPEG2000 30 compression levels (p < 0.05). At comparable file sizes, the JPEG induced a smaller FD difference. In conclusion, lossy compressed images with appropriate compression level may be used for FD calculation.
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Affiliation(s)
- B Güniz Baksi
- School of Dentistry, Department of Oral Diagnosis and Radiology, Ege University, Izmir, Turkey.
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Noujeim M, Geha H, Shintaku W, Bechara B, Kashi KA. Effect of JPEG compression on the diagnostic accuracy of periapical images in the detection of root fracture. Dent Traumatol 2011; 28:233-7. [PMID: 22066949 DOI: 10.1111/j.1600-9657.2011.01076.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The ability of a periapical radiograph to exhibit the fracture depends on many factors including, but not limited to, the resolution of the image. The quality can be reduced by the image compression. The purpose of this study is to evaluate the effect of Joint Photographic Experts Group (JPEG) compressions on the diagnostic capability of periapical images in the detection of root fractures. Ten dry human mandibles containing 151 teeth were used in this study. Mandibles were radiographed with direct digital imaging sensor using the paralleling technique. Four observers detected root fracture on the images saved in one uncompressed and two compressed formats. Receiver operating characteristic (ROC) and anova analyses were performed to compare the performance of the three different systems and evaluate the effect of the compression on the accuracy of root fracture detection. Results did not show any statistically significant difference between the original, large images presented in tagged image file format (TIFF) and the two compressed images (JPEG medium file and JPEG small file images) in the detection of root fractures. The intra-rater comparison showed a significant consistency in the detection of the fracture. The compression reduced the file size considerably (from 1.77 MB to 453 and 95 Kb), but it did not affect the accuracy of root fracture detection. The file size reduction, on the other hand, is very beneficial for image electronic storage and mainly in teleradiology.
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Affiliation(s)
- Marcel Noujeim
- Department of Comprehensive Dentistry, University of Texas Health Science Center, San Antonio, TX 78229, USA
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Yasar F, Yesilova E, Apaydın B. The effects of compression on the image quality of digital panoramic radiographs. Clin Oral Investig 2011; 16:719-26. [PMID: 21732088 DOI: 10.1007/s00784-011-0587-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 06/22/2011] [Indexed: 10/18/2022]
Abstract
Size reduction through compression is an important issue that needs to be investigated for possible effects on image quality. The aim of the present study was to evaluate the subjective image quality of digital panoramic radiographs which were lossless and lossy compressed for the visualization of various anatomical structures. Fifty-five digital panoramic radiographs in Tagged Image File Format (Tiff) were used in the study. Two types of lossy (Joint Photographic Experts Group (Jpeg)) and one type of lossless (Lempel-Ziv-Welch) compression were applied to the original radiographs. These radiographs were evaluated by two observers separately for the visibility of some anatomical structures with visual grading. Mean quality number for each radiograph was obtained. The differences between the mean quality numbers in each compression and original image mode were evaluated with Friedman test. Pair-wise comparisons revealed that there were statistically significant differences between all groups (p = 0.000) for all comparisons except for Jpeg_1 and Jpeg_2 groups. Kappa statistics was used to evaluate inter- and intra-observer agreements. Intra-observer agreements were ranging from 0.229 to 1.000 and inter-observer agreements were ranging from 0.154 to 1.000. The observers had better inter- and intra-observer agreements in highly compressed Jpeg_1 images. The anatomical structures evaluated in this study had better visibility in Tiff images than Jpeg images except for mandibular canal and mental foramen. While Jpeg compressed images offer high inter- and intra-observer agreements, the visibility of anatomical structures are better in Tiff images except for mandibular canal and mental foramen.
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Affiliation(s)
- Füsun Yasar
- Maxillofacial Radiology Department, Dentistry Faculty, Selcuk University, Kampüs, Konya 42079, Turkey.
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Abstract
OBJECTIVE This systematic review evaluates the six most frequently emphasized advantages of working with digital radiography: less working time, lower radiation dose to the patient, fewer retakes and errors, wider dynamic range, easier access to patient information and easier image storage and communication. Moreover, some clinical aspects and possible disadvantages of digital imaging that were not foreseen at the beginning of the digital era, such as patient discomfort, damage to the receptor, degradation of the image, cross-contamination and viewing conditions, were assessed. MATERIAL AND METHODS The literature search used the PubMed database with no limits and was performed during June to August 2009. Search strategies are described in the text for each of the mentioned tasks. A hand search of task-specific journals supplemented the search strategies. RESULTS Time seems to be saved when switching from film to digital imaging in dental practice, a dose reduction may not be obtained, retakes and errors may be increased, the dynamic range may be wider with photostimulable storage phosphor (PSP) plates but not with sensors, the effect on patient information has not been well studied and storage and communication create new challenges with regard to handling large files and image compression. In addition, patient discomfort seems to be pronounced with sensors compared with PSP plates and film, the PSP plate may be scratched in clinical use and a two-layer barrier seems to be needed to prevent contamination of the receptor. The type of monitor may not be of major concern if the image is viewed in a room with subdued light. CONCLUSIONS Not all of the predicted advantages with digital compared to film-based radiography hold true in daily clinical work. Of particular interest is the relationship between number of images, retakes and the dose given to the patient.
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Affiliation(s)
- Ann Wenzel
- Department of Oral Radiology, School of Dentistry, Aarhus University, Vennelyst Boulevard, Aarhus, Denmark.
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Duarte HEM, Vieck R, Siqueira DF, Angelieri F, Bommarito S, Dalben G, Sannomiya EK. Effect of image compression of digital lateral cephalograms on the reproducibility of cephalometric points. Dentomaxillofac Radiol 2009; 38:393-400. [PMID: 19700533 DOI: 10.1259/dmfr/40996636] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To evaluate the influence of JPEG quality factors 100, 80 and 60 on the reproducibility of identification of cephalometric points on images of lateral cephalograms, compared with the Digital Imaging and Communications in Medicine (DICOM) format. METHODS The sample was composed of 30 images of digital lateral cephalograms obtained from 30 individuals (15 males and 15 females) on a phosphor plate system in DICOM format. The images were converted to JPEG with quality factors 100, 80 and 60 with the aid of software, adding up to 90 images. The 120 images (DICOM, JPEG 100, 80 and 60) were blinded and 12 cephalometric points were identified on each image by three calibrated orthodontists, using the x-y coordinate system, on a cephalometric software. RESULTS The results revealed that identification of cephalometric points was highly reproducible, except for the point Orbitale (Or) on the x-axis. The different file formats did not present a statistically significant difference. CONCLUSIONS JPEG images of lateral cephalograms with quality factors 100, 80 and 60 did not present alterations in the reproducibility of identification of cephalometric points compared with the DICOM format. Good reproducibility was achieved for the 12 points, except for point Or on the x-axis.
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Fidler A, Likar B. What Is Wrong with Compression Ratio in Lossy Image Compression? Radiology 2007; 245:299; author reply 299-300. [PMID: 17885201 DOI: 10.1148/radiol.2451062005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Fidler A, Skaleric U, Likar B. The effect of image content on detail preservation and file size reduction in lossy compression. Dentomaxillofac Radiol 2007; 36:387-92. [PMID: 17881596 DOI: 10.1259/dmfr/66171128] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To demonstrate the effect of image content on image detail preservation and file size reduction. METHODS The first set, containing 16 in vitro images with variable projection geometry, exposure time, bone level and number of teeth, was compressed with three compression modes: JPEG quality factor (JPQF), JPEG2000 quality factor (J2QF) and JPEG2000 compression ratio (J2CR). Image detail degradation was evaluated by local mean square error (MSE) on a standardized region of interest (ROI), containing bone. The second set, containing 105 clinical bitewings, was compressed with the same compression modes at 3 quality factors/compression ratios and local MSEs were calculated on two ROIs, containing bone and crown. RESULTS For the first image set, nearly constant MSE was found for the JPQF and J2QF compression modes, while file size depended on projection geometry, exposure time, bone level and the number of teeth. In contrast, file size reduction was nearly constant for the J2CR compression mode, while MSE depended on the abovementioned factors. Similarly, for the second image set, nearly constant MSE and variation of file size reduction were found for JPQF and J2QF but not for the J2CR compression mode. All of these results were consistent for all three quality factors/compression ratios. CONCLUSIONS Constant image detail preservation, crucial for diagnostic accuracy in radiology, can only be assured in QF compression mode in which the file size of the compressed image depends on the original image content. CR compression mode assures constant file size reduction, but image detail preservation depends on image content.
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Affiliation(s)
- A Fidler
- Department of Restorative Dentistry and Endodontics, Faculty of Medicine, University of Ljubljana, Slovenia.
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