能谱CT下肢静脉成像优化:模体研究  

Optimization of Dual-energy Spectral Lower-extremity Computed Tomography Venography Scanning Protocol:Phantom Study

作　　者：王诗耕 浦仁旺[1] 刘义军[1] 方鑫[1] 魏巍 李贝贝 WANG Shigeng;PU Renwang;LIU Yijun;FANG Xin;WEI Wei;LI Beibei(Department of Radiology,The First Affiliated Hospital of Dalian Medical University,Dalian 116011,China)

机构地区：[1]大连医科大学附属第一医院放射科,辽宁大连116011

出　　处：《CT理论与应用研究(中英文)》2025年第1期73-81,共9页Computerized Tomography Theory and Applications

摘　　要：目的:基于模体研究优化能谱下肢CT静脉成像(CTV)方案。方法:在能量CT质控模体的内部孔洞中放置测试插件以模拟临床场景。使用4 mgI/mL碘棒模拟下肢静脉增强;将大小不同的鸭血块放入4 mgI/mL的碘溶液试管中,模拟下肢静脉内的大小血栓。采用Revolution CT对置入碘棒和试管的模体进行CT常规成像(A组)和能谱成像(B组)。A组成像参数:管电压120 kVp,管电流自动调节技术(100~600 mA),噪声指数(NI)为10,采用后置40%的多模型自适应统计迭代重建算法(ASIR-V)进行图像重建;B组成像参数:能谱成像(GSI)模式,管电压80/140 kVp瞬切,管电流采用GSI Assist技术,并根据NI=10、11、12设置3个扫描组。在每个扫描组中重建40~70 keV间隔10 keV的单能量图像,每个单能量图像分别结合后置40%、60%、80%ASIR-V进行图像重建,共得到36组图像。A组和B组其他成像参数均一致。扫描完成后记录A组和B组有效辐射剂量(ED),计算两组碘棒对比噪声比(CNR),评估两组主观图像质量以及识别血栓的真阳性率和假阳性率。结果:B组NI设置为11和12的ED分别比A组低21.5%和32.2%。B组NI为10和11的扫描组中,除了70 keV结合40%ASIR-V和60 keV结合40%ASIR-V的图像外,其余图像的碘棒CNR均高于A组。B组碘棒边缘锐利度得分最高的组别是NI为10的扫描组中,50 keV结合40%、60%ASIR-V的图像,以及NI为11的扫描组中,50 keV结合60%ASIR-V的图像,这3组图像得分均为5(4,5)且优于A组得分3(3,4)。A组图像识别大血栓的真阳性率和假阳性率分别为65.0%和30.0%;识别小血栓的真阳性率和假阳性率分别为55.0%和50.0%。B组NI为10和11的扫描组中,50 keV结合60%ASIR-V图像识别血栓的效能最佳并优于A组,其中识别大血栓的真阳性率和假阳性率分别为90.0%和5.0%,识别小血栓的真阳性率和假阳性率分别为80.0%和5.0%。结论:将NI设置为11,并重建50 keV结合60%ASIR-V的单能量图像是能谱下肢CTV的最佳成像Objective:To optimize a scanning protocol for dual-energy spectral lower-extremity computed tomography venography(CTV)based on a phantom study.Methods:Test plugs were placed in the cavities of an energy CT quality-control phantom to simulate clinical scenarios.A 4 mgI/mL iodine rod was used to mimic venous enhancement in the lower extremities,and duck blood clots of various sizes were placed in test tubes containing 4 mgI/mL of iodine solution to simulate thrombi of different sizes in the lower-extremity veins.Revolution CT was used to perform standard CT imaging(Group A)and spectral imaging(Group B)on phantoms containing iodine rods and test tubes.The imaging parameters for Group A were as follows:tube voltage of 120 kVp,auto tube-current technology(100~600 mA),noise index(NI)of 10,and image reconstruction using 40%posterior multimodel adaptive statistical iterative reconstruction(ASIR-V).The imaging parameters for Group B were spectral imaging(GSI)mode,instantaneous dual tube voltage of 80/140 kVp,tube current with GSI Assist technology,and three scan groups based on NI values of 10,11,and 12.For each scan group,monoenergetic images at 40~70 keV with 10 keV intervals were reconstructed,each combined with 40%,60%,and 80%posterior ASIR-V,which resulted in 36 image sets.Other imaging parameters for Groups A and B were consistent.The effective radiation doses(ED)for Groups A and B were recorded after scanning,and the contrast-to-noise ratio(CNR)of the iodine rods was calculated.Subjective image quality and true-and false-positive rates for thrombus identification were assessed.Results:The EDs for Group B,with NI values of 11 and 12,were 21.5%and 32.2%lower than those for Group A,respectively.In Group B,for the scan groups with NI values of 10 and 11,except for the images at 70 keV combined with 40%ASIR-V and at 60 keV combined with 40%ASIR-V,the CNR of the iodine rods was higher than that in Group A.The highest edge-sharpness scores for the iodine rods in Group B were observed in the scan group with an NI value of

关 键 词：体层摄影术 X线计算机 能谱CT 静脉血栓形成 图像质量 

分 类 号：R814.42[医药卫生—影像医学与核医学]