运用兆伏锥形束计算机断层成像校正千伏计算机断层成像中假牙的金属伪影

发布时间：2018-06-02 12:40

本文选题：计算机成像 + 金属伪影　；参考：《生物医学工程学杂志》2017年05期

【摘要】：本文提出一种运用兆伏锥形束CT(MVCBCT)校正千伏CT(kVCT)图像中假牙金属伪影的新方法。该方法分别用kVCT和MVCBCT扫描佩戴假牙的患者,得到两种CT图像。在kVCT中阈值分割得到金属图像,运用MVCBCT和kVCT融合得到先验图像,对先验图像前投影来替代原始金属区投影,最后通过滤波反投影(FBP)重建图像。将本文方法校正后效果与归一化金属伪影校正法(NMAR)、以MVCBCT为先验图像的归一化金属伪影校正法(NMAR-MV),以及线性插值法(LIMAR)这三种常用伪影校正方法进行比较,计算其归一化均方根偏差(NRMSD)和平均绝对偏差(MAD)。实验结果显示本文方法去除了严重的金属伪影且没有引入其他伪影,基于参考图像计算的NRMSD值和MAD值最小。NMAR、NMAR-MV、LIMAR以及本文方法的NRMSD值分别为21.0%、22.1%、41.9%、17.0%;MAD值分别为232、235、553、205 HU。本文提出的伪影校正方法能较好地去除假牙的金属伪影,大幅改善CT图像质量。
[Abstract]:This paper presents a new method for correction of metal artifacts of denture teeth by using the MVCBCTs of the conical beam of MVV in thousands of volts (CTV / KV) images. In this method, kVCT and MVCBCT were used to scan the patients with dentures, and two CT images were obtained. The metal image is obtained by threshold segmentation in kVCT, a priori image is obtained by MVCBCT and kVCT fusion, and the former image is projected to replace the original metal region projection. Finally, the image is reconstructed by filtering backprojection. The effect of this method is compared with that of normalized metal artifact correction (NMAR), normalized metal artifact correction (NMAR-MVV) using MVCBCT as a priori image, and linear interpolation method (LIMARR). The normalized root mean square deviation (NRMSD) and the mean absolute deviation are calculated. The experimental results show that the method has removed the severe metal artifacts and no other artifacts have been introduced. The minimum value of NRMSD and MAD calculated based on the reference image. NMAR-MVN LIMAR and the NRMSD value of the present method are 21.0 / 22.1 and 41.9 / 17.0 respectively, and the value of mad is 232235553205 HU, respectively. The artifact correction method proposed in this paper can remove metal artifacts of dentures and improve the quality of CT images.
【作者单位】：南京医科大学附属常州第二人民医院放疗科;
【基金】：江苏省自然科学基金(BK20151181) 常州市高层次卫生人才培养工程(2016CZLJ004) 江苏省常州市社会发展项目(CJ20160029)
【分类号】：R814.42;TP391.41

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