两种锥形束CT转化二维图像与传统头颅侧位片定量分析颈椎骨龄的一致性

Consistency between two types of cone-beam CT transformed two-dimensional images and traditional lateral cephalometric radiographs for quantitative analysis of cervical vertebral bone age

背景:传统的头颅侧位片始终存在放大失真、左右重叠不一致等问题,而锥形束CT能真实展现颅面部的三维结构。对锥形束CT进行三维重建,再将所选区域内的锥形束CT转化为二维图像,能使左右侧基本重叠一致且能减小周围组织结构的影响。目的:探究两种不同整合厚度的锥形束CT转化二维图像与传统头颅侧位片定量分析颈椎骨龄的一致性。方法:收集118例青少年正畸患者的锥形束CT及头颅侧位片资料。首先在3D imaging software中对锥形束CT影像进行三维重建,重建后在矢状向界面中分别选择两种不同整合厚度的锥形束CT影像并转化为二维图像,两种图像分别被命名为ICB-1、ICB-2。再运用智贝云对头颅侧位片、ICB-1、ICB-2中的第2颈椎基底部凹陷与椎体下缘所成的角度(@2)、第3颈椎与后面高的比值(AH3/PH3)、第4颈椎高度与宽度的比值(H4/W4)及颈椎骨龄等项目进行测量计算,间隔2周后再随机抽取20例青少年重复上述测量。采用组内相关系数(ICC)法评价3种图像各自测量颈椎骨龄的可重复性;采用配对t检验分析3种图像两两间测量颈椎骨龄的一致性;采用Kappa检验分析3种图像两两组间对颈椎骨龄分期评估的一致性。结果与结论:①除头颅侧位片组AH3/PH3的ICC<0.9,各组其余测量项目ICC均>0.9;②配对t检验结果显示,除ICB-1组与头颅侧位片组、ICB-1组与ICB-2组间AH3/PH3、H4/W4差异有显著性意义(P<0.05),3组其余项目的测量结果两两组间均无统计学差异(P>0.05);③Kappa检验结果显示,3组颈椎骨龄分期评估结果两两组间的Kappa系数均>0.8(P<0.001);④提示ICB-1、ICB-2测量颈椎骨龄的可重复性优于头颅侧位片,头颅侧位片、ICB-1、ICB-2两两组间对颈椎骨龄的测量均有良好的一致性,但考虑到对颈椎椎体结构记录的完整性,ICB-2较ICB-1更适合用于颈椎骨龄定量分析。

BACKGROUND:Traditional lateral cephalometric radiographs always suffer from some problems,such as magnification distortion,left and right overlap inconsistency and so on,while the cone-beam CT can truly display the three-dimensional structure of the craniofacial region.Performing three-dimensional reconstruction of cone-beam CT and then transforming the cone-beam CT in the selected area into the two-dimensional image can make the overlap between the left and right sides consistent and reduce the influence of surrounding tissue structures.OBJECTIVE:To explore the consistency of quantitative analysis of cervical vertebral bone age between two kinds of cone-beam CT transformed twodimensional images with different integrated thicknesses and traditional lateral cephalometric radiographs.METHODS:The cone-beam CT and lateral cephalometric radiograph data of 118 adolescent orthodontic patients were collected.Firstly,the cone-beam CT image was reconstructed in 3D imaging software.After reconstruction,two types of cone-beam CT images with different integrated thicknesses were selected in the sagittal interface and transformed into two-dimensional images,which were named ICB-1 and ICB-2,respectively.The Zhibeiyun system was used to measure and calculate the angle between the concave base of the second cervical vertebra and the lower edge of the vertebral body(@2),the ratio of the third cervical spine to the posterior height(AH3/PH3),the ratio of height to width of the fourth cervical spine(H4/W4)in lateral cephalometric radiograph,ICB-1,ICB-2 and the cervical vertebral bone age.After an interval of two weeks,20 adolescents were randomly selected to repeat the above measurements.The intraclass correlation coefficient(ICC)method was used to evaluate the repeatability of the three images in measuring cervical bone age.Paired t-test was used to analyze the consistency of cervical bone age measurements between the three images.The Kappa test was used to analyze the consistency of cervical vertebral bone age staging assessment between the three images.RESULTS AND CONCLUSION:(1)ICC of AH3/PH3 in the lateral cephalometric radiograph group was<0.9,and the ICC of other measurement items in each group was>0.9.(2)Paired t-test results showed that there were statistical differences in AH3/PH3 and H4/W4 between the ICB-1 group and lateral cephalometric radiograph group and between the ICB-1 group and ICB-2 group(P<0.05),and there were no statistically significant differences in the other items between the three groups(P>0.05).(3)The Kappa test results showed that the Kappa coefficients of the two groups were all more than 0.8 according to the staging of cervical vertebral bone age in three groups(P<0.001).(4)It is indicated that the repeatability of ICB-1 and ICB-2 in the measurement of cervical vertebral bone age is better than that of lateral cephalometric radiographs.Lateral cephalometric radiographs,ICB-1 and ICB-2 have good consistency in the measurement of cervical vertebral bone age,but considering the integrity of cervical vertebra structure,ICB-2 is more suitable for quantitative analysis of cervical vertebral bone age than ICB-1.