基于灰度值差的全冠修复体CBCT 图像伪影评价方法  

Evaluation of artifact of CBCT image of oral full crown prosthesis based on pixel gray value difference

作　　者：沈倍勇[1] 王晓飞 李军心[1] 周琦[1] SHEN Beiyong;WANG Xiaofei;LI Junxin;ZHOU Qi(Department of Stomatology,Shenzhen Second People’s Hospital,The First Affiliated Hospital of Shenzhen University,Shenzhen 518035,Guangdong,China)

机构地区：[1]深圳市第二人民医院深圳大学第一附属医院口腔科

出　　处：《山东大学学报（医学版）》2019年第12期52-56,79,共6页Journal of Shandong University:Health Sciences

基　　金：深圳市科创委科技计划(JCYJ20170306091910957)

摘　　要：目的建立一种基于图像像素灰度值差的口腔全冠修复体CBCT二维断层图像伪影评价方法。方法对离体下颌第一磨牙进行烤瓷全冠预备体的常规预备,根据预备体形态制作钴铬合金烤瓷全冠,将全冠固定在光固化树脂固定板上。用CBCT扫描全冠,将获得的DICOM数据导入MIMICS10.0软件,在二维断层图像中选取伪影明显的一层,利用Photoshop CS6软件测量牙冠的正常灰度值(G0)、正确冠边缘灰度值(GB)、肉眼可见的冠边缘灰度值(GP),从而根据图像各像素点灰度值差定量判定伪影值V和冠边缘的清晰度指标C。结果通过模拟口内扫描环境,成功获得全冠修复体的CBCT扫描数据,根据扫描数据的分析结果,获得钴铬全冠修复体正常全冠灰度值G0为200,根据60个GB值和GP值获得的钴铬烤瓷全冠CBCT二维断层图像伪影评价指数V为[21,43],钴铬全冠CBCT二维断层图像边缘清晰度指标C为51.67%。结论利用图像像素灰度值差明确判定了口腔修复体的冠边缘,并建立了一种定量评价口腔修复体冠周伪影的方法,为患者选择合适的修复体提供一定的参考。Objective To establish a method for the two-dimensional tomographic image’s artifact of oral full crown prosthesis in cone beam computed tomography(CBCT) based on pixel gray difference. Methods A cobalt-chromium porcelain crown was prepared for the full crown preparation of the mandibular first molar, and then was fixed on a photocurable resin fixing plate. The full crown was scanned with CBCT, and then the DICOM data were input into MIMICS10.0 software. The obvious layer of artifacts was selected in the two-dimensional tomogram, and the normal gray value of the crown(G0), correct crown edge gray value(GB) and visible crown edge gray value(GP) were measured with Photoshop CS6 software, thereby quantitatively determining the artifact value V and the crown edge sharpness index C according to the gray value difference of each pixel point of the image. Results By simulating the intraoral scanning environment, the CBCT scan data of the full crown restoration was successfully obtained. According to the analysis results, the normal full crown gray value G0 of cobalt chromium full crown restoration was obtained. According to the GB and GP values, the value of cobalt-chromium-ceramic crown CBCT two-dimensional tomographic image artifact evaluation index V was [21, 43], and the cobalt-chromium full-crown CBCT two-dimensional tomographic imageedge definition index C was 51.67%. Conclusion Using the difference of gray value of image pixels, the crown edge of oral prosthesis can be clearly determined, and a method for quantitative evaluation of crown artifacts in oral prosthesis is established. Clinically, physicians can use the evaluation method for two-dimensional tomographic image artifact in CBCT based on image pixel gray value difference to quantitatively evaluate the artifacts of various restorations, and select appropriate restorations for patients.

关 键 词：口腔颌面锥形束CT 全冠 灰度值 伪影 图像 

分 类 号：R783[医药卫生—口腔医学]