Korpics Mark, Surucu Murat, Mescioglu Ibrahim, Alite Fiori, Block Alec M, Choi Mehee, Emami Bahman, Harkenrider Matthew M, Solanki Abhishek A, Roeske John C
Department of Radiation Oncology, Loyola University Medical Center, Maywood, Illinois.
Department of Radiation Oncology, Loyola University Medical Center, Maywood, Illinois.
Int J Radiat Oncol Biol Phys. 2016 Nov 15;96(4):897-904. doi: 10.1016/j.ijrobp.2016.07.028. Epub 2016 Jul 30.
To quantify, through an observer study, the reduction in metal artifacts on cone beam computed tomographic (CBCT) images using a projection-interpolation algorithm, on images containing metal artifacts from dental fillings and implants in patients treated for head and neck (H&N) cancer.
An interpolation-substitution algorithm was applied to H&N CBCT images containing metal artifacts from dental fillings and implants. Image quality with respect to metal artifacts was evaluated subjectively and objectively. First, 6 independent radiation oncologists were asked to rank randomly sorted blinded images (before and after metal artifact reduction) using a 5-point rating scale (1 = severe artifacts; 5 = no artifacts). Second, the standard deviation of different regions of interest (ROI) within each image was calculated and compared with the mean rating scores.
The interpolation-substitution technique successfully reduced metal artifacts in 70% of the cases. From a total of 60 images from 15 H&N cancer patients undergoing image guided radiation therapy, the mean rating score on the uncorrected images was 2.3 ± 1.1, versus 3.3 ± 1.0 for the corrected images. The mean difference in ranking score between uncorrected and corrected images was 1.0 (95% confidence interval: 0.9-1.2, P<.05). The standard deviation of each ROI significantly decreased after artifact reduction (P<.01). Moreover, a negative correlation between the mean rating score for each image and the standard deviation of the oral cavity and bilateral cheeks was observed.
The interpolation-substitution algorithm is efficient and effective for reducing metal artifacts caused by dental fillings and implants on CBCT images, as demonstrated by the statistically significant increase in observer image quality ranking and by the decrease in ROI standard deviation between uncorrected and corrected images.
通过一项观察者研究，量化使用投影插值算法在锥形束计算机断层扫描（CBCT）图像上减少金属伪影的情况，这些图像包含接受头颈部（H&N）癌症治疗患者的牙科填充物和植入物产生的金属伪影。
将一种插值替代算法应用于包含牙科填充物和植入物产生金属伪影的H&N CBCT图像。从主观和客观两方面评估金属伪影相关的图像质量。首先，要求6名独立的放射肿瘤学家使用5分制评分量表（1 = 严重伪影；5 = 无伪影）对随机排序的盲法图像（减少金属伪影前后）进行排名。其次，计算每张图像内不同感兴趣区域（ROI）的标准差，并与平均评分分数进行比较。
插值替代技术在70%的病例中成功减少了金属伪影。在15名接受图像引导放射治疗的H&N癌症患者的总共60张图像中，未校正图像的平均评分分数为2.3±1.1，而校正图像的平均评分分数为3.3±1.0。未校正图像和校正图像之间的排名分数平均差异为1.0（95%置信区间：0.9 - 1.2，P <.05）。减少伪影后，每个ROI的标准差显著降低（P <.01）。此外，观察到每张图像的平均评分分数与口腔和双侧脸颊的标准差之间存在负相关。
插值替代算法对于减少CBCT图像上由牙科填充物和植入物引起的金属伪影是有效且高效的，这通过观察者图像质量排名的统计学显著提高以及未校正图像和校正图像之间ROI标准差的降低得到证明。
