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Computed gray levels in multislice and cone-beam computed tomography
ارتودنسی
Orthodontics
پژوهشي
Research
<p> <strong>Introduction </strong></p><p> Gray level is the range of shades of gray in the pixels, representing the x-ray attenuation coefficient that allows for tissue density assessments in computed tomography (CT). An in-vitro study was performed to investigate the relationship between computed gray levels in 3 cone-beam CT (CBCT) scanners and 1 multislice spiral CT device using 5 software programs. </p><p> <strong>Methods </strong></p><p> Six materials (air, water, wax, acrylic, plaster, and gutta-percha) were scanned with the CBCT and CT scanners, and the computed gray levels for each material at predetermined points were measured with OsiriX Medical Imaging software (Geneva, Switzerland), OnDemand3D (CyberMed International, Seoul, Korea), E-Film (Merge Healthcare, Milwaukee, Wis), Dolphin Imaging (Dolphin Imaging & Management Solutions, Chatsworth, Calif), and InVivo Dental Software (Anatomage, San Jose, Calif). The repeatability of these measurements was calculated with intraclass correlation coefficients, and the gray levels were averaged to represent each material. Repeated analysis of variance tests were used to assess the differences in gray levels among scanners and materials. </p><p> <strong>Results</strong></p><p> There were no differences in mean gray levels with the different software programs. There were significant differences in gray levels between scanners for each material evaluated (P <0.001). </p><p> <strong>Conclusions</strong></p><p> The software programs were reliable and had no influence on the CT and CBCT gray level measurements. However, the gray levels might have discrepancies when different CT and CBCT scanners are used. Therefore, caution is essential when interpreting or evaluating CBCT images because of the significant differences in gray levels between different CBCT scanners, and between CBCT and CT values. </p><hr><p></p><p> <strong>Source: </strong>American Journal of Orthodontics & Dentofacial Orthopedics </p><p> <a href="http://www.ajodo.org/article/S0889-5406(13)00395-8/abstract" target="_blank"><font color="#0000ff">Full Text</font></a></p>
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http://idai.ir/browse.php?a_code=A-10-32-1826&slc_lang=fa&sid=1
Fabiane
Azeredo
10031947532846008593
10031947532846008593
No
Department of Orthodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
Luciane Macedo
de Menezes
10031947532846008594
10031947532846008594
Yes
Department of Orthodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
Reyes
Enciso
10031947532846008595
10031947532846008595
No
Clinical Dentistry, Division of Dental Public Health and Pediatric Dentistry, Ostrow School of Dentistry, University of Southern California, Los Angeles, Calif
Andre
Weissheimer
10031947532846008596
10031947532846008596
No
Department of Orthodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
Rogério Belle
de Oliveira
10031947532846008597
10031947532846008597
No
Department of Oral and Maxillofacial Surgery, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil