The comparison of landmark identification errors and reproducibility between conventional lateral cephalometric radiography and digital lateral cephalometric radiography

일반두부방사선계측사진과 디지털방사선계측사진의 계측점 식별의 오차 및 재현성에 관한 비교 연구

  • Lee, Yang-Ku (Department of Orthodontics, College of Dentistry, Seoul National University) ;
  • Yang, Won-Sik (Department of Orthodontics, College of Dentistry, Seoul National University) ;
  • Chang, Young-Il (Department of Orthodontics, College of Dentistry, Seoul National University)
  • 이양구 (서울대학교 치과대학 교정학교실) ;
  • 양원식 (서울대학교 치과대학 교정학교실) ;
  • 장영일 (서울대학교 치과대학 교정학교실)
  • Published : 2002.04.30

Abstract

The purpose of this study is to evaluate the reproducibility and errors in landmark identification of conventional lateral cephalometric radiography and digital lateral cephalometric radiography. Fifteen conventional lateral cephalometric radiographs and fifteen digital lateral cephalometric radiographs were selected in adults with no considerations on sex and craniofacial forms. Each landmark was identified and expressed as the coordinate (x, y). The landmarks were classified into 3 groups. The landmarks of the first identification was T1, identification after one week was T2, and identification after one month was T3. The mean and standard deviation of identification errors between replicates were calculated according to the x and y coordinates. The errors between first identification and second identification were expressed as T2-T1(x), T2-T1(y) and those between first identification and third identification were expressed as T3-T1(x), T2-T1(y). Each was divided into conventional lateral cephalometric radiography and digital lateral cephalometric radiography. The independent t- test was used for statistical analysis of identification errors for the evaluation of reproducibility. The results of this study were as follows ; 1. Generally, the mean and standard deviation of landmark identification errors in digital lateral cephalometric radiography was smaller than those of conventional lateral cephalometric radiography. 2. Only a few landmarks showed statistically significant difference in identification error between conventional lateral cephalometric radiography and digital lateral cephalometric radiography. 3. The enhancement of image quality didn't guarantee decrease in landmark identification error and didn't affect tendency of landmark identification error.

본 연구의 목적은 일반두부방사선계측사진과 디지털두부방사선계측사진의 계측점 식별의 오차를 구하여 각각의 영상에서 오차의 특징을 살펴보고 재현성을 비교 평가하는 것이다. 연구 대상은 서울대학교병원 치과진료부 교정과에 내원한 교정 환자 중 18세에서 29세 사이의 성인 환자 중에서 일반두부방사선계측사진군과 디지털두부방사선계측사진군 각각 15명씩 30명을 무작위로 선택하여 연구 대상으로 하였으며 남녀의 구별이나 두개 안면 구조의 형태는 고려하지 않았다. 계측점은 동일인이 시간차를 두고 식별 하였다. 식별 후 각 계측점은 좌표 (x, y)로 표시하였으며, 처음 계측점을 식별한 두부방사선계측사진군을 T1으로, 1 주 후 동일 계측점을 재식별한 두부방사선계측사진군을 T2로, 1 달 후 동일계측점을 재식별한 두부방사선계측사진군을 T3로 분류하였다. 오차의 평균과 표준편차는 x좌표, y좌표로 구분하여 계산하였다. 초기 식별 1주 후 재식별시 오차는 T2-T1(x), T2-T1(y)로, 초기 측정 1달 후 재시별시 오차는 T3-T1(x), T3-T1(y)로 표시하였으며 일반두부방사선계측사진과 디지털두부방사선계측사진으로 각각 나누었다. 재현성의 평가를 위한 오차간의 통계학적인 검정은 independent t-test를 사용하였으며 다음과 같은 결론을 얻었다. 1. 디지털두부방사선계측사진이 일반두부방사선계측사진보다 일반적으로 오차의 평균 및 표준편차가 작았다. 2. 일반두부방사선계측사진의 오차와 디지털두부방사선계측사진의 오차가 통계학적으로 유의성 있는 차이를 보인 항목은 드물었다. 3.상의 향상을 통한 오차의 개선은 한계가 있었으며 상이 향상되더라도 각 계측점의 오차 의 경향은 크게 변하지 않았다.

Keywords

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