Effect of digitization parameters on periapical radiographic image quality with regard to anatomic landmarks
Efeitos dos parâmetros de digitalização na qualidade da imagem radiográfica periapical com relação a reparos anatômicos
Gonçalves, Andréa; Nicoli, Giovanni Antonio; Zamperini, Camila Andrade; Hebling, Josimeri; Gonçalves, Marcelo
Rev. odontol. UNESP, vol.40, n1, p.25-29, 2011
Abstract
The aim of this study was to evaluate the influence of digitization parameters on periapical radiographic image quality, with regard to anatomic landmarks. Digitized images (n = 160) were obtained using a flatbed scanner with resolutions of 300, 600 and 2400 dpi. The radiographs of 2400 dpi were decreased to 300 and 600 dpi before storage. Digitizations were performed with and without black masking using 8-bit and 16-bit grayscale and saved in TIFF format. Four anatomic landmarks were classified by two observers (very good, good, moderate, regular, poor), in two random sessions. Intraobserver and interobserver agreements were evaluated by Kappa statistics. Inter and intraobserver agreements ranged according to the anatomic landmarks and resolution used. The results obtained demonstrated that the cement enamel junction was the anatomic landmark that presented the poorest concordance. The use of black masking provided better results in the digitized image. The use of a mask to cover radiographs during digitization is necessary. Therefore, the concordance ranged from regular to moderate for the intraobserver evaluation and concordance ranged from regular to poor for interobserver evaluation.
Keywords
Radiography, dental, radiographic image enhancement, image processing, computer-assisted
Resumo
O objetivo deste estudo foi avaliar a influência dos parâmetros de digitalização na qualidade da imagem radiográfica digital, com relação a reparos anatômicos. Para isso, imagens radiográficas foram digitalizadas por meio de um scanner (n = 160) com resoluções de 300, 600 e 2400 dpi. As imagens de 2400 dpi foram ainda diminuídas para 300 e 600 dpi antes do armazenamento. As digitalizações foram realizadas com e sem máscaras pretas utilizando-se escalas de cinza de 8-bit e 16-bit e salvas em formato TIFF. Para avaliar a influência dos parâmetros de digitalização na qualidade da imagem radiográfica digitalizada, quatro reparos anatômicos foram classificados por dois observadores (muito boa, boa, moderada, regular, pobre) em duas ocasiões diferentes. As concordâncias intra e inter-observadores foram avaliadas por meio do teste Kappa. Os resultados obtidos demonstraram que as concordâncias intra e inter-observadores variaram em função dos reparos anatômicos e da resolução utilizada. A junção cemento esmalte foi o reparo anatômico que apresentou a mais pobre concordância. A utilização da máscara preta favoreceu a qualidade da imagem digitalizada e seu uso é necessário para cobrir a radiografia durante o processo de digitalização. Portanto, a concordância variou de regular a moderada para a avaliação intra-observador e de regular a pobre para a concordância inter-observador.
Palavras-chave
Radiografia dentária, radiografia digital, processamento de imagem assistida por computador
References
1. C hristensen GJ. Why switch to digital radiography? J Am Dent Assoc. 2004; 135: 1437-9.
2. D unn SM, Kantor ML. Digital radiology: facts and fictions. J Am Dent Assoc. 1993; 124: 38-47.
3. Sakurai T, Matsuki T, Nakamura K, Kashima I, Lee DL, Cheung LK, Jeromin LS. The development of a new direct digital extra-oral radiographic system prototype using a thin-film transistor panel. Dentomaxillofac Radiol. 1998; 27: 172-7.
4. Vandre RH, Pajak JC, Farman TT , Farman AG. Technical comparison of seven digital intra-oral dental X-ray sensors. Dentomaxillofac Radiol. 1997; 26: 282-3.
5. Kimmes NS, Saini TS, Carroll LR. Comparison of clinician agreement during visualization of conventional and digitized bitewing radiographs. Gen Dent. 2006; 54: 182-5.
6. Furkart AJ, Dove SB, McDavid WD, Nummikoski P, Matteson S. Direct Digital radiography for the detection of periodontal bone lesions. Oral Surg Oral Med Oral Pathol. 1992; 74: 652-60.
7. MØystad A, Savanaes DB, Larheim TA, Gröndahl H-G. Effect of image magnification of digitized bitewing radiographs on approximal caries detection: an in vitro study. Dentomaxillofac Radiol. 1995; 24: 255-9.
8. D ove SB, McDavid WD. A comparison of conventional intra-oral radiography and computer imaging techniques for the detection of proximal surface dental caries. Dentomaxillofac Radiol. 1992; 21: 127-34.
9. Grassl U, Schulze RKW. In vitro perception of low-contrast features in digital, film, and digitized dental radiographs: a receiver operating characteristic analysis. Oral Sur Oral Med Oral Pathol Oral Radiol Endod. 2007; 103: 694-701.
10. Peker I, Toraman AM, Usalan G, Altunkaynak B. The comparison of subjective image quality in conventional and digital panoramic radiography. Indian J Dent Res. 2009; 20: 21-5.
11. Abreu Júnior M, Tyndall DA, Platin E, Ludlow JB, Phillips C. Two- and tree-dimensional imaging modalities for the detection of caries. A comparison between film, digital radiography and tuned aperture computed tomography (TACT). Dentomaxillofac Radiol. 1999; 28: 152-7.
12. Berkhout WER, Verheij JGC, Syriopoulos K, Li G, Sanderink GCH, van der Stelt PF. Detection of proximal caries with high-resolution and standard resolution digital radiographic systems. Dentomaxillofac Radiol. 2007; 36: 204-10.
13. Fidler A, Likar B, Skaleric U. Lossy JPEG compression: easy to compress, hard to compare. Dentomaxillofac Radiol. 2006; 35: 67-73.
14. Attaelmanan A, Borg E, Gröndahl HG. Digitisation and display of intra-oral. Dentomaxillofac Radiol. 2000; 29: 97-102.
15. Janhom A, van Ginkel FC, van Amerongen JP, van der Stelt PF. Scanning resolution and the detection of approximal caries. Dentomaxillofac Radiol. 2001; 30: 166-71.
16. Radan E, Price C. Evaluation of digital and geometric unsharpness in dental radiographs using an endodontic file model. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002; 93: 208-14.
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