单能量CT成像结合去金属伪影算法在儿童漏斗胸金属支架植入术后评估中的应用  

Value of monoenergetic imaging in children with internal fixation of pectus excavatum by thoracic stent

作　　者：李成龙 胡春峰 LI Cheng-long;HU Chun-feng(Department of Medical Imaging,The Affiliated Hospital of Xuzhou Medical University,Jiangsu 221000,China)

机构地区：[1]徐州医科大学附属医院放射科,江苏徐州221000 [2]徐州医科大学附属徐州儿童医院医学影像科,江苏徐州221000

出　　处：《影像诊断与介入放射学》2020年第1期37-41,共5页Diagnostic Imaging & Interventional Radiology

摘　　要：目的探讨能谱CT最佳单能量成像结合去金属伪影算法(MRA)在儿童漏斗胸胸廓内支架固定术后成像中的价值。方法A组:20例漏斗胸胸廓内支架植入术后的患儿,能谱扫描模式,扫描参数:80~140 kV,200 mA,ASIR-V:50%,最佳单能量加MAR重组,以10 keV为间隔重组40~140 keV图像。B组:20例同样治疗的患儿,常规胸部平扫,100 kV,自动毫安,噪声指数(NI):10,ASIR-V:50%,计算支架两端伪影区与背部肌肉的CT差值(△CT)和CT伪影指数(AI),记录剂量长度乘积(DLP)并计算有效剂量(ED)。由两位副主任医师对两组病例读片并主观评分,评分标准1~5分,并对评分进行一致性分析。结果A组40~60 keV单能量图像△CT值(711.34±27.23 HU,465.77±36.25 HU,415.50±34.64 HU)较B组(408.33±15.14 HU)高,差异有统计学意义(P<0.05),A组70~140 keV单能量图像△CT值较B组低,差异有统计学意义(P<0.05),其中110~140 keV图像的△CT值(41.47±6.21 HU,40.38±4.79 HU,40.37±3.65 HU,42.15±3.22 HU)明显降低,A组40~70 keV单能量图像AI值(274±20.61,169±10.91,104.77±17.61,85.48±10.86)较B组(56.02±6.33)高,差异有统计学意义(P<0.05),A组80~140 keV单能量图像AI值较B组低,差异有统计学意义(P<0.05),其中100~140 keV图像AI值(16.91±2.55,17.98±2.21,14.56±3.52,16.39±2.34,18.62±3.12)明显降低,A组DLP(90.22±6.31 mGy·cm)和ED(1.52±0.15 mSv)大于B组DLP(36.43±4.20 mGy·cm)和ED(0.62±0.34 mSv),差值有统计学意义(P<0.05),A组100~140 keV图像均大于4分;40~90 keV图像及B组图像小于4分,读片结论一致性良好。结论能谱扫描模式下的单能量图结合MAR算法可以有效去除漏斗胸胸廓内支架造成的伪影,但辐射剂量高于普通胸部平扫。Objective To evaluate the image quality of gemstone spectral imaging (GSI) in children after internal fixation of pectus excavatum with thoracic stent. Methods Thoracic CT of 40 children with history of internal fixation of pectus excavatum by thoracic stent was retrospectively analyzed. In group A (20 children), CT was performed with GSI scan, metal artifact reduction software (MARs) mode, and 40-140 keV image reconstruction. The remaining 20 children (group B) underwent conventional unenhanced 100 kV CT. The CT difference (△CT) and CT artifact index (AI) between the artifact areas at both ends of the stents and the back muscles were calculated. The dose length product (DLP) was recorded and the effective dose (ED) was determined. Two radiologists evaluated the image quality subjectively using a 5-point scoring system. Inter-reader agreement was analyzed by Kappa test. The image quality and radiation dose were compared by t-test. Results The △CT of 40-60 keV single energy image (711.34±27.23 HU, 465.77±36.25 HU, 415.50±34.64 HU) in group A was significantly (P<0.05) higher than that in group B (408.30±15.14 HU). The △CT of 70-110 keV especially the 110-140 keV single energy image in group A (41.47±6.21 HU, 40.38±4.79 HU, 40.37±3.65 HU, 42.15±3.22 HU) was significantly (P<0.05) lower than that in group B. The AI of 40-70 keV single energy image in group A (274±20.61, 169±10.91, 104.77±17.61, 85.48±10.86) was significantly (P<0.05) higher than that in group B (56.02±6.33) whereas the AI of 100-140 keV image (16.91±2.55, 17.98±2.21, 14.56±3.52, 16.39±2.34, 18.62±3.12) was significantly (P<0.05) lower. The DLP (90.22±6.31 mGy*cm) and ED (1.52±0.15 mSv) in group A were significantly (P<0.05) higher than those (36.43±4.20 mGy*cm, 0.62±0.34 mSv) in group B. The 100-140 keV images in group A had higher scores greater than 4 whereas the scores of 40-90 keV images and group B images were less than 4. Conclusion GSI with MARs can effectively remove the artifacts caused by the thoracic stent alth

关 键 词：单能量成像 体层摄影术 X线计算机 儿童 漏斗胸 伪影 

分 类 号：R816.92[医药卫生—放射医学] R726.5[医药卫生—临床医学]