Imaging Science in Dentistry

Korean Academy of Oral and Maxillofacial Radiology (대한영상치의학회)
권호 표지

Study of threshold and opacity in three-dimensional CT volume rendering of oral and maxillofacial area

구강악안면영역의 3차원 CT 영상 재형성시 역치 및 불투명도에 대한 연구

  • Choi, Mun-Kyung (Department of Oral and Maxillofacial Radiology, Dental Research Institute and BK21, School Dentistry, Seoul National University) ;
  • Lee, Sam-Sun (Department of Oral and Maxillofacial Radiology, Dental Research Institute and BK21, School Dentistry, Seoul National University) ;
  • Huh, Kyung-Hoe (Department of Oral and Maxillofacial Radiology, Dental Research Institute and BK21, School Dentistry, Seoul National University) ;
  • Yi, Won-Jin (Department of Oral and Maxillofacial Radiology, Dental Research Institute and BK21, School Dentistry, Seoul National University) ;
  • Choi, Soon-Chul (Department of Oral and Maxillofacial Radiology, Dental Research Institute and BK21, School Dentistry, Seoul National University)
  • 최문경 (서울대학교 치의학대학원 구강악면방사선학교실, 치학연구소 및 BK21) ;
  • 이삼선 (서울대학교 치의학대학원 구강악면방사선학교실, 치학연구소 및 BK21) ;
  • 허경회 (서울대학교 치의학대학원 구강악면방사선학교실, 치학연구소 및 BK21) ;
  • 이원진 (서울대학교 치의학대학원 구강악면방사선학교실, 치학연구소 및 BK21) ;
  • 최순철 (서울대학교 치의학대학원 구강악면방사선학교실, 치학연구소 및 BK21)
  • Published : 2009.03.31
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Abstract

Purpose: This study was designed to determine a proper threshold value and opacity in three-dimensional CT volume rendering of oral and maxillofacial area. Materials and Methods: Three-dimensional CT data obtained from 50 persons who were done orthognatic surgery in department of oral and maxillofacial radiology of Seoul National University retrospectively. 12 volume rendering post-processing protocols of combination of threshold(100HU, 150HU, 221HU, 270HU) and opacity (58%, 80%, 90%) were applied. Five observers independently evaluated image quality using a five-point range scale. The results were analyzed by receiver operating characteristic curves, ANOVA and Kappa value. And three oromaxillofacial surgeons chose the all images that they thought proper clinically in the all of images. Results: Analysis using ROC curves revealed the area under each curve which indicated a diagnostic accuracy. The highest diagnostic accuracy appear with 100HU and 58% opacity. and the lowest diagnostic accuracy appear with 221HU and 58% opacity that are being used protocol in department of oral and maxillofacial radiology of Seoul National University. But, no statistically significant difference was noted between any of the protocols. And the number of proper images clinically that chosen by three oromaxillofacial surgeons is the largest in the cases of protocol 8 (221HU, opacity 80%) and protocol 11 (270HU, opacity 80%) in one after the other. Conclusion: Threshold and opacity in volume rendering can be controled easily and these can be causes of making an diagnostic accuracy. So we need to select proper values of these factors.

Keywords

References

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