双能量CT虚拟单能量成像能级设置对炎症性肠病图像质量的影响  

Effect of a noise-optimized virtual monoenergetic reconstruction technique on dual-energy CT for image quality of inflammatory bowel disease

作　　者：杨海涛[1] 吴雄 蒋博[1] 邓凯[1] 孙剑宁[1] 梅习龙[1] YANG Haitao;WU Xiong;JIANG Bo;DENG Kai;SUN Jianning;MEI Xilong(Department of Radiology,Second Xiangya Hospital,Central South University,Changsha 410011,China)

机构地区：[1]中南大学湘雅二医院放射科,长沙410011

出　　处：《中南大学学报（医学版）》2018年第8期875-881,共7页Journal of Central South University ：Medical Science

摘　　要：目的:评估炎症性肠病(inflammatory bowel disease,IBD)患者腹部双能量CT(dual-energy CT,DECT)扫描不同能级噪声优化的虚拟单能量图像(noise-optimized virtual monoenergetic imaging,VMI+)的主观和客观图像质量,得出最佳重建参数,提高IBD诊断准确率。方法:选取2016年4月到2017年6月确诊为IBD的32名患者腹部DECT扫描图像进行线性融合(M_0.6)、VMI+、传统虚拟单能量图像(virtual monoenergetic imaging,VMI)重建,虚拟能级为40~100 ke V,间隔为10 ke V。以病变肠段部位的图像信噪比(signal-to-noise ratio,SNR)和对比噪声比(contrast-to-noise ratio,CNR)作为客观图像质量评价标准,主观图像质量评价由3名放射科医生对总体图像质量、锐利度、病变轮廓、噪声4个方面进行双盲评估。结果:客观图像质量评价最佳重建参数为40 ke V VMI+(SNR 8.28±2.34;CNR 5.10±2.10),优于线性融合图像(SNR 5.82±1.44;CNR 1.53±0.86)和传统VMI(P<0.01)。主观图像质量评价中,50 ke V VMI+总体图像质量(均值4.80)高于其他图像(P<0.01),40和50 ke V VMI+锐利度最高(均值分别为4.14和4.25,P=0.415),40 ke V VMI+显示病变轮廓能力评分高于其他图像(均值4.52,P<0.01)。100 ke V VMI+和100 ke V VMI噪声最低(均值分别为4.58和4.40,P≥0.11)。结论:相比于线性融合和传统VMI重建,低能级VMI+可显著提高IBD病变部位的腹部DECT扫描图像的主观和客观图像质量。Objective： To assess the value of noise-optimized virtual monoenergetic imaging （VMI＋） reconstruction technique on objective and subjective image quality in patients with inflammatory bowel disease （IBD） undergoing abdominal dual-energy computed tomography （DECT）. Methods： Datasets from 32 patients （22 men, 10 women） with IBD, who underwent abdominalECT, were reconstructed by using the standard linearly blended （M-0.6）, traditional monoenergetic （VMI） and VMI＋ algorithms in 10-keV intervals from 40-100 keV. Attenuation in IBD lesions was measured to perform objective evaluation using signal-to-noise （SNR） and contrast-to-noise ratios （CNR）. Subjective evaluation was performed by 3 independent blinded radiologists using S-point Likert scales. The overall image quality, image sharpness, lesion delineation, and image noise were analyzed. Results： Mean SNR and CNR peaked at 40 keV VMI＋ series （SNR 8.28±2.34, CNR 5.10±2.10） and they were significantly higher than those in linearly blended （SN1K 5.82± 1.44, CNR 1.53±0.86） and all VMI series （all P〈0.01）. Subjective image parameter was the highest for the SO keV VMI＋ series regarding overall image quality （mean 4.80, all P〈0.01）. The highest image sharpness scores were observed at 40 and S0 keV VMI＋ reconstructions （mean 4.14 and 4.25, respectively; P=0.41S）. VMI＋ series at 40 keV provided the highest lesion delineation （mean 4.52, all P〈0.01）. Image noise was low at the 100 keV VMI＋ and VMI series （mean 4.58 and 4.40, respectively; P≥0.11）. Conclusion： Low-keV VMI＋ reconstructions improves SNR, CNR, and subjective image quality significantly in patients with IBD.

关 键 词：双能量CT 噪声优化的虚拟单能量成像 炎症性肠病 

分 类 号：R816.5[医药卫生—放射医学]