Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba, São Paulo, Brazil.
Orofacial Pathologies, Imaging and Biotherapies Lab, Université de Paris, UR 2496, Montrouge, France.
Dentomaxillofac Radiol. 2021 May 1;50(4):20200450. doi: 10.1259/dmfr.20200450. Epub 2020 Dec 11.
To evaluate the influence of exomass-related metal artefacts on the detection of simulated vertical root fracture (VRF) in cone-beam computed tomography (CBCT).
20 teeth were endodontically instrumented and VRF was induced in half of them. All teeth were individually placed in an empty socket of a human mandible. Metallic materials were differently arranged in the exomass [zone outside of the field of view (FOV) but between the X-ray source and the receptor] and/or endomass (zone inside of the FOV), and CBCT scans were obtained. Four radiologists evaluated the presence of VRF using a 5-point scale. Sensitivity, specificity, and area under the receiver operating curve (AUC) were compared using ANOVA. Also, the tooth of interest was replaced with a tube filled with a radiopaque solution and all CBCT scans were repeated to analyse the data objectively. Mean grey and noise values were obtained from the tube and compared using ANOVA followed by Tukey's test (α = 0.05).
Mean grey values were significantly lower and noise was significantly higher when metallic materials were present in the endomass or both the exomass and endomass. Sensitivity, specificity, and AUC were not influenced by the artefacts from the metallic materials irrespective of the arrangement condition.
Exomass-related metal artefacts did not influence the diagnosis of simulated VRF in CBCT.
评估外源性相关金属伪影对锥形束计算机断层扫描（CBCT）中模拟垂直根折（VRF）检测的影响。
20 颗牙齿进行根管器械治疗，其中一半诱导 VRF。所有牙齿均单独放置在人类下颌骨的空牙槽中。金属材料在外源性（视野外但在射线源和接收器之间的区域）和/或内源性（视野内的区域）中以不同方式排列，并获得 CBCT 扫描。四位放射科医生使用 5 分制评估 VRF 的存在情况。使用方差分析比较灵敏度、特异性和接收器操作特性曲线（AUC）下的面积。此外，用充满不透射线溶液的管代替感兴趣的牙齿，并重复所有 CBCT 扫描以客观地分析数据。从管中获得平均灰度值和噪声值，并使用方差分析和 Tukey 检验（α=0.05）进行比较。
当金属材料存在于内源性或外源性和内源性时，平均灰度值显著降低，噪声显著增加。无论排列条件如何，金属材料的伪影均不影响诊断的灵敏度、特异性和 AUC。
外源性相关金属伪影不会影响 CBCT 中模拟 VRF 的诊断。
