AIM:To evaluate the feasibility of low contrast medium and radiation dose for hepatic computed tomography(CT) perfusion of rabbit VX2 tumor.METHODS:Eleven rabbits with hepatic VX2 tumor underwent perfusion CT scanning...AIM:To evaluate the feasibility of low contrast medium and radiation dose for hepatic computed tomography(CT) perfusion of rabbit VX2 tumor.METHODS:Eleven rabbits with hepatic VX2 tumor underwent perfusion CT scanning with a 24-h interval between a conventional tube potential(120 k Vp) protocol with 350 mg I/m L contrast medium and filtered back projection,and a low tube potential(80 k Vp) protocol with 270 mg I/m L contrast medium with iterative reconstruction.Correlation and agreement among perfusion parameters acquired by the conventional and low dose protocols were assessed for the viable tumor component as well as whole tumor.Image noise and tumor-to-liver contrast to noise ratio during arterial and portal venous phases were evaluated.RESULTS:A 38% reduction in contrast medium dose(360.1 ± 13.3 mg I/kg vs 583.5 ± 21.5 mg I/kg,P < 0.001) and a 73% decrease in radiation dose(1898.5 m Gy·cm vs 6951.8 m Gy·cm) were observed.Interestingly,there was a strong positive correlation in hepatic arterial perfusion(r = 0.907,P < 0.001;r = 0.879,P < 0.001),hepatic portal perfusion(r = 0.819,P = 0.002;r = 0.831,P = 0.002),and hepatic blood flow(r = 0.945,P < 0.001;r = 0.930,P < 0.001) as well as a moderate correlation in hepatic perfusion index(r = 0.736,P = 0.01;r = 0.636,P = 0.035) between the low dose protocol with iterative reconstruction and the conventional protocol for the viable tumor component and the whole tumor.These two imaging protocols provided a moderate but acceptable agreement for perfusion parameters and similar tumorto-liver CNR during arterial and portal venous phases(5.63 ± 2.38 vs 6.16 ± 2.60,P = 0.814;4.60 ± 1.27 vs 5.11 ± 1.74,P = 0.587).CONCLUSION:Compared with the conventional protocol,low contrast medium and radiation dose with iterative reconstruction has no significant influence on hepatic perfusion parameters for rabbits VX2 tumor.展开更多
目的通过建立冠状动脉增强扫描的体外模型,在保证冠脉CT血管造影（CTA）图像质量能够满足诊断的前提下,探讨低辐射剂量和低浓度对比剂在冠脉CTA检查中的应用。方法将非离子型对比剂碘克沙醇注射液（270 mg I/ml）采用等渗盐水进行稀释,...目的通过建立冠状动脉增强扫描的体外模型,在保证冠脉CT血管造影（CTA）图像质量能够满足诊断的前提下,探讨低辐射剂量和低浓度对比剂在冠脉CTA检查中的应用。方法将非离子型对比剂碘克沙醇注射液（270 mg I/ml）采用等渗盐水进行稀释,其浓度为3.24、4.32、5.40、6.48、7.56、8.64、9.72 mg I/ml,以上液体分别置于7支相同长度的输液管内,按碘溶液浓度由低至高进行编号（1~7）。每次将3支输液管固定在鲜猪心上,模仿三支冠脉走行。采用256层螺旋CT将管电压设为80 k V,电流采用105、210、315 m A,再固定电流105 m A时变换不同电压80、100及120 k V,记录输液管中CT值、噪声值SD、信噪比SNR、对比噪声比CNR、辐射剂量（CTDIvol、DLP、ED）及图像质量评分,并进行统计学分析。结果管电压固定80 k V时,改变管电流（105、210、315 m A）,CT值、SD、SNR、CNR及图像质量评分差异无统计学意义（P〉0.05）;而CTDIvol、DLP、ED差异有统计学意义（P〈0.05）,105 m A较210 m A及315 m A ED分别降低了50.62%和67.01%。管电压固定105 m A时,改变管电流（80、100、120 k V）,3组不同管电压间图像质量评分及SD、SNR、CNR无明显差异（P〉0.05）;而其管内CT值、辐射剂量差异有统计学意义（P〈0.05）,80 k V较100 k V及120 k V ED分别降低了47.80%和65.84%。管电压固定80 k V时,改变管电流（105、210、315 m A）,或当管电流固定105 m A时,改变管电压（80、100、120 k V）,碘溶液组（1~7）图像质量评分差异无统计学意义（P〉0.05）。结论采用256层螺旋CT对冠脉体模扫描表明,在不影响诊断质量的前提下,低剂量CT扫描参数与低浓度对比剂联合迭代重建技术冠脉CTA成像是可行的。展开更多
基金National Natural Science Foundation of China,No.NSFC 81171389Key Program of Basic Research from Shanghai Municipal Science and Technology Commission,No.12JC1406500the Program of Shanghai Municipal Health Outstanding Discipline Leader,No.XBR 2013110
文摘AIM:To evaluate the feasibility of low contrast medium and radiation dose for hepatic computed tomography(CT) perfusion of rabbit VX2 tumor.METHODS:Eleven rabbits with hepatic VX2 tumor underwent perfusion CT scanning with a 24-h interval between a conventional tube potential(120 k Vp) protocol with 350 mg I/m L contrast medium and filtered back projection,and a low tube potential(80 k Vp) protocol with 270 mg I/m L contrast medium with iterative reconstruction.Correlation and agreement among perfusion parameters acquired by the conventional and low dose protocols were assessed for the viable tumor component as well as whole tumor.Image noise and tumor-to-liver contrast to noise ratio during arterial and portal venous phases were evaluated.RESULTS:A 38% reduction in contrast medium dose(360.1 ± 13.3 mg I/kg vs 583.5 ± 21.5 mg I/kg,P < 0.001) and a 73% decrease in radiation dose(1898.5 m Gy·cm vs 6951.8 m Gy·cm) were observed.Interestingly,there was a strong positive correlation in hepatic arterial perfusion(r = 0.907,P < 0.001;r = 0.879,P < 0.001),hepatic portal perfusion(r = 0.819,P = 0.002;r = 0.831,P = 0.002),and hepatic blood flow(r = 0.945,P < 0.001;r = 0.930,P < 0.001) as well as a moderate correlation in hepatic perfusion index(r = 0.736,P = 0.01;r = 0.636,P = 0.035) between the low dose protocol with iterative reconstruction and the conventional protocol for the viable tumor component and the whole tumor.These two imaging protocols provided a moderate but acceptable agreement for perfusion parameters and similar tumorto-liver CNR during arterial and portal venous phases(5.63 ± 2.38 vs 6.16 ± 2.60,P = 0.814;4.60 ± 1.27 vs 5.11 ± 1.74,P = 0.587).CONCLUSION:Compared with the conventional protocol,low contrast medium and radiation dose with iterative reconstruction has no significant influence on hepatic perfusion parameters for rabbits VX2 tumor.
文摘目的通过建立冠状动脉增强扫描的体外模型,在保证冠脉CT血管造影（CTA）图像质量能够满足诊断的前提下,探讨低辐射剂量和低浓度对比剂在冠脉CTA检查中的应用。方法将非离子型对比剂碘克沙醇注射液（270 mg I/ml）采用等渗盐水进行稀释,其浓度为3.24、4.32、5.40、6.48、7.56、8.64、9.72 mg I/ml,以上液体分别置于7支相同长度的输液管内,按碘溶液浓度由低至高进行编号（1~7）。每次将3支输液管固定在鲜猪心上,模仿三支冠脉走行。采用256层螺旋CT将管电压设为80 k V,电流采用105、210、315 m A,再固定电流105 m A时变换不同电压80、100及120 k V,记录输液管中CT值、噪声值SD、信噪比SNR、对比噪声比CNR、辐射剂量（CTDIvol、DLP、ED）及图像质量评分,并进行统计学分析。结果管电压固定80 k V时,改变管电流（105、210、315 m A）,CT值、SD、SNR、CNR及图像质量评分差异无统计学意义（P〉0.05）;而CTDIvol、DLP、ED差异有统计学意义（P〈0.05）,105 m A较210 m A及315 m A ED分别降低了50.62%和67.01%。管电压固定105 m A时,改变管电流（80、100、120 k V）,3组不同管电压间图像质量评分及SD、SNR、CNR无明显差异（P〉0.05）;而其管内CT值、辐射剂量差异有统计学意义（P〈0.05）,80 k V较100 k V及120 k V ED分别降低了47.80%和65.84%。管电压固定80 k V时,改变管电流（105、210、315 m A）,或当管电流固定105 m A时,改变管电压（80、100、120 k V）,碘溶液组（1~7）图像质量评分差异无统计学意义（P〉0.05）。结论采用256层螺旋CT对冠脉体模扫描表明,在不影响诊断质量的前提下,低剂量CT扫描参数与低浓度对比剂联合迭代重建技术冠脉CTA成像是可行的。
