单源双探测器能谱CT合成的单能级图像对下腔静脉成像质量的影响  

Effect of Monochromatic Energy Image Synthesized from Dual-layer Detector Spectral CT on Imaging of Inferior Vena Cava

作　　者：邹颖 王世伟 李涛[2] 陈科 张兴华[2] 罗春材 杨立[2] ZOU Ying;WANG Shiwei;LI Tao;CHEN Ke;ZHANG Xinghua;LUO Chuncai;YANG Li(Department of Radiology,Chinese PLA General Hainan Hospital,Sanya,Hainan 572013,China;Department of Radiology,Chinese PLA General Hospital,Beijing 100853,China;Philips Healthcare China,Shanghai 200233,China)

机构地区：[1]中国人民解放军总医院海南医院放射科,海南三亚572013 [2]中国人民解放军总医院放射科,北京100853 [3]飞利浦医疗保健,上海200233

出　　处：《中国医学科学院学报》2020年第3期359-363,共5页Acta Academiae Medicinae Sinicae

摘　　要：目的探讨双层探测器能谱CT合成的单能级图像对下腔静脉成像质量的影响。方法对39例临床怀疑有腹部疾病的患者进行前瞻性研究,采用单源双探测器能谱CT进行腹部CT检查。以3 ml/s的速度注射60 ml碘帕醇对比剂(320 mg/ml),3 min后进行延迟期扫描。原始图像被重建成常规混合能量图像和基于能谱的图像(SBI),获得40、50、60、70 keV的单能级图像。分别测量常规混合能量图像及40、50、60、70 keV单能级图像下腔静脉的CT值、噪声、信噪比(SNR)和相对于腰大肌的对比噪声比(CNR)。单能级40~70 keV图像与常规混合能量(120 kVp)图像进行比较,采用方差分析的方法比较5组间CT值、噪声、SNR和CNR,选择显示下腔静脉的最佳单能级图像。结果5组间下腔静脉CT值、噪声、SNR和CNR差异均有统计学意义(P均<0.05)。40和50 keV单能量组的SNR和CNR均明显高于其他组(P均<0.05),40 keV单能量组的SNR明显高于50 keV组(P=0.002),40和50 keV单能量组的CNR差异无统计学意义(P=0.630)。结论40 keV是单源双探测器能谱CT下腔静脉成像的最佳单能级,有助于下腔静脉疾病的诊断。Objective To evaluate the effect of monochromatic energy image on inferior vena cava imaging quality on dual-layer detector spectral CT.Methods Totally 39 patients who were clinically suspected of abdominal disease and referred to perform contrast-enhanced computed tomography(CT)were prospectively enrolled and underwent abdominal examination using a single-source,dual-detector spectral CT.The delayed phase scan was performed 3 minutes after injection of 60 ml of iopamidol(320 mg/ml)at a rate of 3 ml/s.The raw images were reconstructed to obtain conventional mixed energy images and spectral based images(SBI).The 40,50,60,and 70 keV single energy images were obtained.The CT value,noise,and signal-to-noise(SNR)of inferior vena cava and the contrast-to-noise(CNR)of inferior vena cava relative to psoas major on conventional mixed energy images and the 40,50,60,70 keV single energy images were measured.The SNRs and CNRs on monoenergetic 40-70 keV images were compared with polychromatic 120 kVp images.ANOVA was used to compare the CT value,noise,SNR,and CNR among these five groups.The optimal monoenergetic image set was chosen.Results The differences in CT value,noise,SNR,CNR of inferior vena cava were statistically significant among five groups(all P<0.05).The SNR and CNR in 40 keV group and 50 keV group were significantly higher than those in other groups(all P<0.05).The SNR of 40 keV group was significantly higher than that of 50 keV group(P=0.002).The CNR of 40 keV group was not statistical different compared with that of 50 keV group(P=0.630).Conclusion 40 keV is the optimal monoenergetic energy level for the inferior vena cava on dual-layer detector spectral CT and may be valuable for the diagnosis of inferior vena cava disease.

关 键 词：双探测器能谱CT 下腔静脉成像 最佳单能级 

分 类 号：R445.1[医药卫生—影像医学与核医学] R445.2[医药卫生—诊断学]