摘要
目的通过体外实验探讨宝石CT能谱成像(GSI)技术血管成像的最佳单能量图像。方法将非离子型对比剂(碘海醇,300mgI/ml)用生理盐水稀释成10种不同浓度的溶液置于2ml硬塑料试管中,浓度依次为1.04、1.17、1.56、2.08、2.34、3.13、4.17、4.69、6.25及9.38mgI/ml。用猪肉包裹试管后置入水槽中,并加以固定。使用能谱CT进行GSI模式扫描,利用GSI处理/重建平台获得40～70keV间距为5keV的7种单能量图像及140kVp混合能量图像,比较各单能量图像及混合能量图像的CNR、SNR和噪声;并根据管壁边缘锐利度、肌肉及脂肪组织的显示情况及噪声3个方面对图像质量进行主观评价,得出图像质量评分,并进行统计学分析。结果 50keV(13.28±3.06)及55keV图像的CNR(14.68±3.75)高于其他单能量图像和混合能量图像(P<0.001),50keV及55keV图像间差异无统计学意义(P=0.139)。55keV图像的SNR(22.18±3.95)高于其他单能量图像和混合能量图像(P<0.001)。与混合能量图像比较,65keV图像的噪声降低程度(23.08%)优于其他单能量图像(P=0.002)。55keV的图像质量评分(11.76±0.33)高于其他单能量图像和混合能量图像(χ2=73.05,P<0.001)。结论本实验中,55keV图像是能谱CT GSI血管成像的最佳单能量图像,图像质量优于140kVp混合能量图像。
Objective To investigate the optimal monochromatic image for CT vasculargraphy using gemstone spectral imaging （GSI） in vitro. Methods Ten test tubes of solution varied in iodine concentrations （1.04, 1.17, 1.56, 2.08, 2.34, 3. 13, 4.17, 4.69, 6.25, 9.38 mgI/ml） embedded in pork which were fixed in a water tank. The tank was scanned with spectral CT using GSI mode. All the data were transferred to GSI viewer to obtain a set of polychromatic images （140 kVp） and 7 sets of monochromatic images （40-70 keV, interval of 5 keV）. CNR, SNR and noise were compared a mong 7 sets monochromatic images and polychromatic images. The image quality was assessed according to sharp edged de gree of the test tube, displaying of muscle and fat as well as the noise. Results CNR of 50 keV （13.28±3.06） and 55 keV （14.68±3.75） images were the highest in all sets of monochromatic images and polyehromatic images （P〈0. 001 ）. There was no significant difference between 50 keV and 55 keV （P=0. 139）. SNR of 55 keV image （22. 18±3.95） was the high est in all sets of monochromatic images and polychromatic images （P〈0. 001）. Compared to the polychromatic image, reduction of the noise of 65 keV image （23.08 %） was higher than those of other monochromatic images. And the subjective image quality scales in 55 keV （11.76±0.33） were the highest in all sets of monochromatic images and polychromatic images （χ^2 =73.05, P〈0. 001）. Conclusion In GSI of vasculargraphy, 55 keV is the optimal monochromatic level for in vitro CT vasculargraphy to offer the overall good image quality, imaging quality is better than that of polychromatic images.
出处
《中国医学影像技术》
CSCD
北大核心
2011年第11期2340-2343,共4页
Chinese Journal of Medical Imaging Technology
