能谱 CT 成像技术在减除金属植入物伪影方面的应用价值  

The value of gemstone spectral imaging in reducing metallic implants artifacts

作　　者：潘自兵[1] 赵凯[1] 海录[1] 宫亚琳[1] 平学军[1] 

机构地区：[1]宁夏医科大学附属心脑血管病医院放射科,宁夏银川750004

出　　处：《实用放射学杂志》2015年第6期1014-1017,共4页Journal of Practical Radiology

摘　　要：目的：研究宝石 CT 能谱成像技术（GSI）和多种伪影去除序列（MARS）在消除金属植入物伪影方面的应用价值,并获得图像质量最佳单能量图像。方法选取本院21例含金属植入物的患者,行 GSI 扫描,获得140 kVp 的混合能量图像；并应用能谱分析软件,获得40~140 keV（以10 keV 为间距）共11组单能量图像,将其重建成单能量加 MARS 图像,由3名放射医师采用盲法对2种成像方式的图像质量行主观评价。选取每组图像中伪影最重层面及无伪影层面行感兴趣区（ROI）CT 值和噪声（SD）值的测量,并计算对比噪声比（CNR）和伪影指数（AI）。对能谱图像组和混合能量图像的 CNR 和 AI 进行配对 t 检验。结果2种成像方式的 CNR 在40~120 keV 均存在统计学意义（P 0.05）。2种成像方式的 AI 在40~60 keV 无统计学意义（P 〉0.05）,在70~140 keV存在明显统计学差异（P 〈0.05）,且单能量加 MARS 图像的 AI 值在110 keV 最低（AI=26.95±9.64）,120 keV 次之（AI=27.05±10.04）。结论能谱 CT 成像技术和 MARS 技术可以有效减少受检部位的金属伪影和硬化伪影,图像质量明显优于常规混合能量图像,且在70 keV 时 CNR 最佳,在110~120 keV 时去除伪影效果最优,对金属植入物术后患者的影像学诊断有重要意义。Objective To evaluate the value of gemstone spectral imaging （GSI）and multi artifact reduction system（MARs）in re-ducing metallic implants artifacts,and find the best monochromatic images.Methods Twenty-one patients with metal implants in our hospital receievd GSI examination ,MARS reconstruction and polychromatic images（140 kVp）.Eleven groups of monochromatic and MARS images were obtained from 40 keV to 140 keV every interval of 10 keV by the special GSI viewer ,respetively.Subjective image quality of two methods were assessed by 3 radiologists in consensus.For every patient one group monochromatic images and blend enery images were selected two heaviest artifacts level and no artifacts level,the CT value and the standard deviations（SD）value of the region of interest（ROI）were meatured of artifacts.Contrast-to-noise ratio（CNR）and artifacts index（AI）were also caculated and were analyzed with paired-t test.Results There was significant statistical differences of CNR between energy spectral images and blend energy images in energy level of 40 to 120 keV（P 0.05）,and the optimal CNR was acquired at the energy level of 70 keV（CNR=8.75±3.28）.The value of AI for two mehtods has no difference in energy level scope 40 to 60 keV（P 〉0.05）,there was significant statistical differences of AI between energy spectral images and blend energy images in energy level of 70 to 140 keV（P 〈0.05）,and the lowest of AI（AI=26.95±9.64）was ac-quired at 1 10 keV images.Conclusion The energy spectral CT possess superiority in decreasing the artifacts and will provide high image quality in the metal implants.Gemstone spectral CT has great significance for postoperative patients with metal implants in imaging diagnosis.

关 键 词：能谱成像 金属伪影 图像质量 计算机体层成像 

分 类 号：R814.42[医药卫生—影像医学与核医学] R814.49[医药卫生—放射医学]