摘要
目的：探讨能谱CT单能量成像技术去除胸部增强CT腋静脉和锁骨下静脉对比剂伪影（BHA）的应用价值。方法回顾性分析2014年2至4月49例成年患者行胸部增强CT能谱（GSI）模式扫描的影像资料。扫描数据在工作站以GSI viewer浏览器重建出140 kVp混合能量图像和11组单能量图像（40~140 keV，间隔10 keV重建1组），使用单因素方差分析对比分析组间伪影区噪声、对比噪声比（CNR）、BHA和CT值差值。结果对比140 kVp混合能量图像及11组单能量图像，70 keV图像的CNR最高，为7.2±1.8（F=11.5，P〈0.01），组织对比度与传统成像方式更为接近，但其BHA、CT值差值均较高，分别为（47.1±19.0）和（71.7±60.9）HU，图像质量受伪影影响大。110 keV能在保证CT值差值最小的情况下最大程度去除对比剂硬化伪影（P〈0.05）。其BHA及CT值差值分别为（20.9±6.5）和（10.0±7.7）HU，CNR虽然较70 keV略有降低，但组间差异无统计学意义（P=0.099）。结论能谱CT单能量成像可有效去除碘对比剂产生的硬化伪影，提高图像质量。临床工作中可根据需要结合110和70 keV单能量图像共同进行诊断。
Objective To assess the value of monochromatic images of gemstone spectral CT for reducing beam-hardening artifacts （BHA） around axillary vein and subclavian vein due to the utility of contrast agent in the chest enhanced CT scan. Methods Images of the arterial phase were acquired using gemstone spectral imaging （GSI） mode in 49 adult patients who underwent chest enhanced CT scan. All data were transferred to AW4.6 workstation to generate 1 set of 140 kVp conventional polychromatic images and 11 sets of monochromatic images in 40—140 keV. The measurement and comparison of image noise, contrast to noise ratio （CNR）, average BHA and the CT value difference were performed between polychromatic image and each monochromatic image with one-way ANOVA. Results Compared with the 140 kVp conventional polychromatic images and 11 sets of monochromatic images, the soft tissue contrast of 70 keV images was closer to the traditional imaging method, with the highest CNR（7.2 ± 1.8,F=11.5,P〈0.01）. But at the same time, the BHA and CT value difference of 70 keV images were obviously increased [（47.1±19.0） and （71.7±60.9）HU, respectively] and the image quality was influenced greatly by the artifacts. At 110 keV, the BHA could be minimized（P〈0.05） and the CT value difference was the lowest [（20.9±6.5） and （10.0 ± 7.7）HU, respectively]. Even though the CNR of 110 keV images was lower than that of 70 keV, but there was no significant difference between these two group （P=0.099）. Conclusions The monochromatic images of Gemstone spectral CT can effectively reduce beam-hardening artifacts of iodine contrast agent and improve the image quality. In clinical application, it can be combined with 110 keV and 70 keV images to make the diagnosis.
出处
《中华放射学杂志》
CAS
CSCD
北大核心
2016年第11期825-828,共4页
Chinese Journal of Radiology
