Three-dimensional image analysis of the skull using variable CT scanning protocols-effect of slice thickness on measurement in the three-dimensional CT images

두개골의 3차원 영상 분석을 위한 전산화단층촬영 방법의 비교-상층 두께가 3차원 영상의 계측에 미치는 영향

  • Jeong Ho-Gul (Department of Oral & Maxillofacial Radiology, Oral Science Research Center, College of Dentistry, Yonsei University, Human Identification Research Institute, Yonsei University) ;
  • Kim Kee-Deog (Department of Oral & Maxillofacial Radiology, Oral Science Research Center, College of Dentistry, Yonsei University, Human Identification Research Institute, Yonsei University) ;
  • Park Hyok (Department of Oral & Maxillofacial Radiology, Oral Science Research Center, College of Dentistry, Yonsei University) ;
  • Kim Dong-Ook (Department of Diagnostic Radiology, Yonsei University) ;
  • Jeong Haijo (Department of Diagnostic Radiology, Yonsei University) ;
  • Kim Hee-Joung (Department of Diagnostic Radiology, Human Identification Research Institute, Yonsei University) ;
  • Yoo Sun Koo (Department of Medical Engineering, Human Identification Research Institute, Yonsei University) ;
  • Kim Yong Oock (Department of Plastic Surgery, College of Medicine, Yonsei University) ;
  • Park Chang-Seo (Department of Oral & Maxillofacial Radiology, Oral Science Research Center, College of Dentistry, Yonsei University)
  • 정호걸 (연세대학교 치과대학 구강악안면방사선학교실, 구강과학연구소, 연세대학교 개인식별연구소) ;
  • 김기덕 (연세대학교 치과대학 구강악안면방사선학교실, 구강과학연구소, 연세대학교 개인식별연구소) ;
  • 박혁 (연세대학교 치과대학 구강악안면방사선학교실, 구강과학연구소) ;
  • 김동욱 (연세대학교 의과대학 진단방사선과학교실) ;
  • 정해조 (연세대학교 의과대학 진단방사선과학교실) ;
  • 김희중 (연세대학교 의과대학 진단방사선과학교실, 연세대학교 개인식별연구소) ;
  • 유선국 (연세대학교 의학공학교실, 연세대학교 개인식별연구소) ;
  • 김용욱 (연세대학교 의과대학 성형외과학교실) ;
  • 박창서 (연세대학교 치과대학 구강악안면방사선학교실)
  • Published : 2004.09.01

Abstract

Purpose : To evaluate the quantitative accuracy of three-dimensional (3D) images by means of comparing distance measurements on the 3D images with direct measurements of dry human skull according to slice thickness and scanning modes. Materials and Mathods : An observer directly measured the distance of 21 line items between 12 orthodontic landmarks on the skull surface using a digital vernier caliper and each was repeated five times. The dry human skull was scanned with a Helical CT with various slice thickness (3, 5, 7 mm) and acquisition modes (Conventional and Helical). The same observer measured corresponding distance of the same items on reconstructed 3D images with the internal program of V-works 4.0/sup TM/(Cybermed Inc., Seoul, Korea). The quantitative accuracy of distance measurements were statistically evaluated with Wilcoxons' two-sample test. Results: 11 line items in Conventional 3 mm, 8 in Helical 3mm, 11 in Conventional 5mm, 10 in Helical 5mm, 5 in Conventional 7mm and 9 in Helical 7mm showed no statistically significant difference. Average difference between direct measurements and measurements on 3D CT images was within 2mm in 19 line items of Conventional 3mm, 20 of Helical 3mm, 15 of Conventional 5mm, 18 of Helical 5mm, II of Conventional 7mm and 16 of Helical 7mm. Conclusion: Considering image quality and patient's exposure time, scanning protocol of Helical 5mm is recommended for 3D image analysis of the skull in CT.

Keywords