辐射剂量和机型对瞬时kVp切换单源双能CT物质分离技术肝脏铁与脂肪定量评估的影响
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摘要
目的:探讨辐射剂量、机型对瞬时kVp切换单源双能CT肝脏铁和脂肪沉积定量评估的影响。方法:制作肝脏铁沉积体模(铁浓度分别为50.000、25.000、12.500、6.250、3.125、0mg/mL大鼠肝脏匀浆液)、脂肪沉积体模(脂肪体积百分比分别为100%、60%、30%、10%、0%大鼠肝脏匀浆液):①应用256-MDCT分别以管电流200、320、485mA扫描体模,管电压80、140kVp瞬时切换,相应CTDIvol分别为4.88,8.21,12.64mGy;②应用64-MDCT扫描体模,管电流为375mA、CTDIvol为12.92mGy。以标准算法分别重建铁(水)、脂肪(水)基物质图像,将图像传至ADW4.6工作站,利用GSI分析软件(GSI Viewer)分析,于体模内每个试管横断面中心放置3个直径为6mm、面积为28.26mm2圆形感兴趣区(ROI),然后记录其平均值为各ROI虚拟铁浓度值(VIC)、虚拟脂肪浓度值(VFC),先对256-MDCT 3组辐射剂量下的VIC、VFC分别进行单因素方差(ANOVA)分析;再分析256-MDCT辐射剂量为12.64mGy下、64-MDCT辐射剂量为12.92mGy下,VIC与肝脏铁浓度(LIC)相关性,VFC与肝实际脂肪浓度(LFC)的相关性。结果:①ANOVA分析显示3组CTDIvol下肝铁沉积模型VIC组间差异P=0.993(F=0.007),组间差异无统计学意义;三组CTDIvol下肝脂肪沉积模型VFC组间差异P=0.976(F=0.024),组间差异无统计学意义;即不同辐射剂量下测得的3组VIC、VFC组间差异均无统计学差异。②256-MDCT组CTDIvol为12.64mGy下与64-MDCT组CTDIvol为12.92mGy下,两组铁沉积模型VIC与LIC均呈高度正相关,相关系数r=0.998(P=0.000),256-MDCT组12.64mGy下拟合铁的线性方程为y=2.179x-2.923(y为LIC,x为VIC,R2=0.996),64-MDCT组12.92mGy下拟合铁的线性方程为y=2.714x+16.971(R~2=0.996);两组脂肪沉积模型VFC与LFC均呈高度正相关,相关系数r=1.000(P=0.000);256-MDCT组12.64mGy下Fat线性方程:y=0.064x+23.44(y为LFC,x为VFC,R~2=0.868);64-MDCT组375mA下Fat线性方程:y=0.09x-60.442 (R~2=0.994)。结论:辐射剂量对双能量CT物质分离技术定量评估肝脏铁、脂肪沉积无影响;256-MDCT及64-MDCT所测的VIC与LIC、VFC与LFC均呈高度正相关,两个机型在铁定量评估VIC与LIC的相关性、脂肪定量评估VFC与LFC的相关性无差异;本研究为今后临床低辐射剂量CT扫描下定量评估肝脏铁、脂肪沉积奠定基础。
Objective:To investigate the effect of different radiation doses and machine type on the quantification of the liver-iron fraction and liver-fat fraction by using fast-kilovolt-peak switching dual-energy CT imaging and material decomposition technique.Methods:Liver-iron mixture samples and liver-fat mixture samples were prepared.For the liver-iron model(model A),six homogeneous liver-iron mixed samples with iron content of 50.000,25.000,12.500,6.250,3.125 and 0 mg/mL.For the liver-fat model(model B),five homogeneous liver-fat mixed samples with fat content of 1.0,0.6,0.3,0.1 and 0 mg/mL.①All samples were scanned on 256-MDCT using GSI mode with rapid tube voltage switching between 80～140 kVp,and with tube current 200 mA,320 mA,485 mA,respectively,and the CT dose index(CTDIvol)were 4.88,8.21,12.64 mGy,respectively.②The 64-MDCT(Discovery CT750 HD,GE Healthcare)was used to scan model A and model B.The tube current was 375 mA and CTDIvol were 12.92 mGy,and the remaining scanning parameters were consistent with Revolution CT.The standard algorithm of 1.25 mm was used to reconstruct Iron(water)and Fat(water)based matter images,respectively.After the CT scan reconstructed imaging data were processed with GSI imaging analysis software package(GSI Viewer)for material decomposition and characterization.Iron concentration(on iron-water bases)and fat concentration(on fat-water bases)measured with consistent region of interests(ROIs)placed in the tube center with a diameter of 6 mm and area of 28.26 mm2.Each sample was recorded at three different regions for average and statistical analysis.Oneway ANOVA was performed on three groups of VIC and VFC in 256-MDCT scan by using SPSS 20.0 software.The correlation between VIC and liver iron concentration(LIC),the correlation between VFC and the liver fat concentration(LFC)was analyzed under 256-MDCT radiation dose of 12.64 mGy and 64-MDCT radiation dose of 12.92 mGy.Results:①In model A,there was no significant difference in VIC between the three groups of CTDIvol,P value of ANOVA test was 0.993.In model B,there was no significant difference in VFC between the three groups of CTDIvol,P value of ANOVA test was 0.976.There was no significant difference between the three groups of VIC and VFC measured by different radiation doses.②Both 256-MDCT and 64-MDCT resulted good linear relationship between the VIC and LIC,and the correlation coefficient was 0.998(P<0.001)and 0.998(P<0.001),respectively.And the linear correlation equation of model A were y=2.179 x-2.923(y stands for LIC,x stands for VIC,R2=0.996),and y=2.714 x+16.971(R2=0.996),respectively.Both 256-MDCT and 64-MDCT resulted good linear relationship between the VFC and LFC,and both of the correlation coefficient was 1.000(P<0.001).The linear correlation equation of model B scanned by256-MDCT and 64-MDCT were y=0.064 x+23.44(y stands for LFC,x stands for VFC,R2=0.868),and y=0.09 x-60.442(R2=0.994),respectively.Conclusion:Different radiation doses had no effect on the iron content quantification and fat content quantification by using fast-kilovolt-peak switching dual-energy CT imaging and material decomposition techniques.The correlation between VIC and LIC,VFC and LFC measured by 256-MDCT and 64-MDCT was highly positive.There was no difference in the correlation between VFC and LFC,LIC and VIC of the two machine types.This study laid a foundation for the quantification of iron and fat in liver under low dose of CT in clinic.
Objective:To investigate the effect of different radiation doses and machine type on the quantification of the liver-iron fraction and liver-fat fraction by using fast-kilovolt-peak switching dual-energy CT imaging and material decomposition technique.Methods:Liver-iron mixture samples and liver-fat mixture samples were prepared.For the liver-iron model(model A),six homogeneous liver-iron mixed samples with iron content of 50.000,25.000,12.500,6.250,3.125 and 0 mg/mL.For the liver-fat model(model B),five homogeneous liver-fat mixed samples with fat content of 1.0,0.6,0.3,0.1 and 0 mg/mL.①All samples were scanned on 256-MDCT using GSI mode with rapid tube voltage switching between 80～140 kVp,and with tube current 200 mA,320 mA,485 mA,respectively,and the CT dose index(CTDIvol)were 4.88,8.21,12.64 mGy,respectively.②The 64-MDCT(Discovery CT750 HD,GE Healthcare)was used to scan model A and model B.The tube current was 375 mA and CTDIvol were 12.92 mGy,and the remaining scanning parameters were consistent with Revolution CT.The standard algorithm of 1.25 mm was used to reconstruct Iron(water)and Fat(water)based matter images,respectively.After the CT scan reconstructed imaging data were processed with GSI imaging analysis software package(GSI Viewer)for material decomposition and characterization.Iron concentration(on iron-water bases)and fat concentration(on fat-water bases)measured with consistent region of interests(ROIs)placed in the tube center with a diameter of 6 mm and area of 28.26 mm2.Each sample was recorded at three different regions for average and statistical analysis.Oneway ANOVA was performed on three groups of VIC and VFC in 256-MDCT scan by using SPSS 20.0 software.The correlation between VIC and liver iron concentration(LIC),the correlation between VFC and the liver fat concentration(LFC)was analyzed under 256-MDCT radiation dose of 12.64 mGy and 64-MDCT radiation dose of 12.92 mGy.Results:①In model A,there was no significant difference in VIC between the three groups of CTDIvol,P value of ANOVA test was 0.993.In model B,there was no significant difference in VFC between the three groups of CTDIvol,P value of ANOVA test was 0.976.There was no significant difference between the three groups of VIC and VFC measured by different radiation doses.②Both 256-MDCT and 64-MDCT resulted good linear relationship between the VIC and LIC,and the correlation coefficient was 0.998(P<0.001)and 0.998(P<0.001),respectively.And the linear correlation equation of model A were y=2.179 x-2.923(y stands for LIC,x stands for VIC,R2=0.996),and y=2.714 x+16.971(R2=0.996),respectively.Both 256-MDCT and 64-MDCT resulted good linear relationship between the VFC and LFC,and both of the correlation coefficient was 1.000(P<0.001).The linear correlation equation of model B scanned by256-MDCT and 64-MDCT were y=0.064 x+23.44(y stands for LFC,x stands for VFC,R2=0.868),and y=0.09 x-60.442(R2=0.994),respectively.Conclusion:Different radiation doses had no effect on the iron content quantification and fat content quantification by using fast-kilovolt-peak switching dual-energy CT imaging and material decomposition techniques.The correlation between VIC and LIC,VFC and LFC measured by 256-MDCT and 64-MDCT was highly positive.There was no difference in the correlation between VFC and LFC,LIC and VIC of the two machine types.This study laid a foundation for the quantification of iron and fat in liver under low dose of CT in clinic.
引文
[1]Porter J,Garbowski M.Consequences and management of iron overload in sickle cell disease[C].Hematology Am Soc Hematol Educ Program,2013:447-456.
[2]Marsella M,Borgna-Pignatti C.Transfusional iron overload and iron chelation therapy in thalassemia major and sickle cell disease[J].Hematol Oncol Clin North Am,2014,28(4):703-727.
[3]黄璐,韩瑞,夏黎明.分析1.5T与3.0T MR定量评价体外铁浓度模型比较研究[J].放射学实践,2017,32(10):1014-1017.
[4]Tomoko Hyodo,Masatoshi Hori,Peter Lamb.Multimaterial decomposition algorithm for the quantifcation of liver fat content by using fast-Kilovolt-Peak switching dual-energy CT:experimental validation[J].Radiology,2017,282(2):381-389.
[5]Ma J,Song ZQ,Yan FH.Separation of hepatic iron and fat by dual-source dual-energy computed tomography based on material decomposition:an animal study[J].PLoS One,2014,9(10):e110964.
[6]石磊,陈新月,李剑,等.双能量CT的多参数分析及其在肿瘤成像中的应用[J].中国医疗设备,2017,32(11):18-22.
[7]马静,董海鹏,宋琼,等.双能CT扫描参数和算法对定量检测伴脂肪沉积肝脏铁含量影响的实验研究[J].中华放射学杂志,2014,48(4):333-336.
[8]严福华.重视腹部CT和MR新技术的量化研究和临床应用[J].中华放射学杂志,2013,47(2):101-103.
[9]许霄,黄求理,朱雪君,等.双能CT不同能量组合、重建算法及ROI选择对家兔肝铁定量测量的影响[J].放射学实践,2018,33(4):344-348.
[10]Joe E,Kim SH,Lee KB,et al.Feasibility and accuracy of dualsource dual-energy CT for noninvasive determination of hepatic iron accumulation[J].Radiology,2012,262(1):126-135.
[11]严福华,林晓珠.双能量CT的多参数分析和临床应用[J].中国医学计算机成像杂志,2013,19(1):1-3.
[12]Goldberg HI,Cann CE,Moss AA,et al.Noninvasive quantitation of liver iron in dogs with hemochromatosis using dual-energy CTscanning[J].Invest Radiol,1982,17(4):375-380.
[13]Fischer MA,Reiner CS,Raptis D,et al.Quantification of liver iron content with CT-added value of dual energy[J].Eur Radiol,2011,21(8):1727-1732.
[14]盖立平,刘爱莲,孙美玉,等.管电流对能谱CT成像的影响[J].实用放射学杂志,2015,31(11):1860-1864.
[2]Marsella M,Borgna-Pignatti C.Transfusional iron overload and iron chelation therapy in thalassemia major and sickle cell disease[J].Hematol Oncol Clin North Am,2014,28(4):703-727.
[3]黄璐,韩瑞,夏黎明.分析1.5T与3.0T MR定量评价体外铁浓度模型比较研究[J].放射学实践,2017,32(10):1014-1017.
[4]Tomoko Hyodo,Masatoshi Hori,Peter Lamb.Multimaterial decomposition algorithm for the quantifcation of liver fat content by using fast-Kilovolt-Peak switching dual-energy CT:experimental validation[J].Radiology,2017,282(2):381-389.
[5]Ma J,Song ZQ,Yan FH.Separation of hepatic iron and fat by dual-source dual-energy computed tomography based on material decomposition:an animal study[J].PLoS One,2014,9(10):e110964.
[6]石磊,陈新月,李剑,等.双能量CT的多参数分析及其在肿瘤成像中的应用[J].中国医疗设备,2017,32(11):18-22.
[7]马静,董海鹏,宋琼,等.双能CT扫描参数和算法对定量检测伴脂肪沉积肝脏铁含量影响的实验研究[J].中华放射学杂志,2014,48(4):333-336.
[8]严福华.重视腹部CT和MR新技术的量化研究和临床应用[J].中华放射学杂志,2013,47(2):101-103.
[9]许霄,黄求理,朱雪君,等.双能CT不同能量组合、重建算法及ROI选择对家兔肝铁定量测量的影响[J].放射学实践,2018,33(4):344-348.
[10]Joe E,Kim SH,Lee KB,et al.Feasibility and accuracy of dualsource dual-energy CT for noninvasive determination of hepatic iron accumulation[J].Radiology,2012,262(1):126-135.
[11]严福华,林晓珠.双能量CT的多参数分析和临床应用[J].中国医学计算机成像杂志,2013,19(1):1-3.
[12]Goldberg HI,Cann CE,Moss AA,et al.Noninvasive quantitation of liver iron in dogs with hemochromatosis using dual-energy CTscanning[J].Invest Radiol,1982,17(4):375-380.
[13]Fischer MA,Reiner CS,Raptis D,et al.Quantification of liver iron content with CT-added value of dual energy[J].Eur Radiol,2011,21(8):1727-1732.
[14]盖立平,刘爱莲,孙美玉,等.管电流对能谱CT成像的影响[J].实用放射学杂志,2015,31(11):1860-1864.