摘要
目的探讨全模型迭代重建(IMR)技术联合低管电压MSCT扫描在肾动脉成像中降低辐射剂量及控制图像质量的应用价值。方法前瞻性连续搜集行腹盆腔动态增强CT扫描的120例患者,根据患者体质量指数(BMI)分为A组(BMI≤22 kg/m^2)、B组(22 kg/m^2<BMI≤25 kg/m^2)两组,再根据管电压及重建算法不同各分出3个亚组,A1-FBP组(120 kV,FBP),A2-iDose^4组(80 kV,iDose^4),A2-IMR组(80 kV,IMR);B1-FBP组(120 kV,FBP),B2-iDose^4组(100 kV,iDose^4),B2-IMR组(100 kV,IMR)。测量各组肾动脉主干CT值,分别对各组肾动脉MIP图像质量进行评分,记录各组容积CT剂量指数(CTDIvol)、剂量长度乘积(DLP),计算各组信噪比(SNR)、对比噪声比(CNR)、用碘总量、图像灵敏度(FOM)及有效剂量(ED)。A1与A2,B1与B2用碘总量、DLP、ED比较使用独立样本t检验;A、B两组的3个亚组间(A1-FBP、A2-iDose^4与A2-IMR,B1-FBP、B2-iDose^4与B2-IMR)肾动脉主干CT值、SNR、CNR、FOM比较使用单因素方差分析;肾动脉图像质量评分的比较采用秩和检验。结果 A1与A2组CTDIvol、DLP及ED分别为16.9 m Gy、(886.1±46.0)m Gy·cm、(13.3±0.7)m Sv;4.9 m Gy、(261.9±12.5)m Gy·cm、(3.9±0.2)m Sv。B1与B2组上述数据分别为16.9 m Gy、(929.6±45.3)m Gy·cm、(14.0±0.7)m Sv;10.1 m Gy、(559.9±26.4)m Gy·cm、(8.4±0.4)m Sv。组间上述数据差异有统计学意义(P<0.01)。A1-FBP、A2-iDose^4与A2-IMR组SNR、CNR、FOM及图像质量评分分别为10.1±3.0、13.2±3.5、(11.0±5.9)mGy^(-1)、3.0(2.0,3.0);14.5±4.1、15.6±3.9、(52.5±26.8)mGy^(-1)、3.0(2.0,3.0);34.9±13.3、44.4±12.2、(339.3±237.8)mGy^(-1)、3.0(3.0,4.0)。B1-FBP、B2-iDose^4与B2-IMR组上述数据分别为9.0±2.4、9.7±2.7、(6.0±3.7)mGy^(-1)、3.0(2.0,3.0);13.3±3.3、14.9±2.9、(22.8±9.3)mGy^(-1)、3.0(2.0,3.0);28.4±9.0、38.5±10.3、(157.0±86.9)mGy^(-1)、3.0(3.0,4.0)。A1-FBP与A2-iDose^4,B1-FBP与B2-iDose^4组间图像质量评分差异无统计学意义(P>0.05),余组间各数据差异有统计学意义(P<0.01)。结论应用IMR较iDose^4可更显著的提高图像SNR、CNR及图像质量。根据患者BMI采用适当的低管电压(80 kV或100 kV)联合IMR重建技术进行肾动脉成像,在降低患者辐射剂量的同时可获得理想的图像。
Objective To evaluate the application of iterative model reconstruction（IMR） combined with low tube voltage MSCT for reducing radiation dose and controlling image quality in renal artery CT angiography（CTA）.Methods120 cases of abdominal and pelvic enhancement CT scans were prospectively and continuously collected in our hospital and they were divided into Group A（BMI≤22 kg/m^2） and Group B（22 kg/m^2 BMI≤25 kg/m^2） according to the patient＇s BMI.They were then further divided into 3 subordinate groups according to different tube voltages and reconstruction algorithms.The groups were divided as follows： Group A1-FBP（（120 k V,FBP; Group A2-iDose^4（80 k V,iDose^4）; Group A2-IMR（80 k V,IMR） and Group B1-FBP（（120 k V,FBP）; Group B2-iDose^4（100 k V,iDose^4）; Group B2-IMR（100 k V,IMR）.We measured each group＇s renal artery CT value,graded each group＇s renal artery MIP image quality,recorded each group＇s CTDIvol,dose length product（DLP）,calculated each group＇s signal noise ratio（SNR）,contrast noise ratio（CNR）,iodine consumption amount,figure of merit（FOM） and effective dose（ED）.We compared the iodine consumption amount,DLP,ED of A1A2,B1B2 with independent-sample t test.We also compared the renal artery CT value,SNR,CNR,FOM of Group A and Group B＇s three subordinate groups（A1-FBP,A2-iDose^4 and A2-IMR; B1-FBP,B2-iDose^4 and B2-IMR） with one-way analysis of variance.Lastly,we compared the renal artery image quality with rank sum test.Results The CTDIvol,DLP and ED of Group A1 and Group A2 were 16.9m Gy,（886.1 ± 46.0） m Gy · cm,（13.3 ± 0.7） m Sv; 4.9m Gy,（261.9 ± 12.5） m Gy·cm,（3.9 ± 0.2） m Sv respectively.The data mentioned above for Group B1 and Group B2 were 16.9m Gy and（929.6 ± 45.3） m Gy·cm,（14.0 ± 0.7） m Sv; 10.1m Gy、（559.9 ± 26.4）m Gy·cm and（8.4 ± 0.4） m Sv respectively.The difference of the data mentioned above among groups had statistic significance（P 0.01）.The SNR,CNR,FOM and image quality grades of A1-FBP,A2-iDose^4 and A2-IMR were 10.1 ±3.0,13.2 ± 3.5,（11.0 ± 5.9） mGy^（-1）,3.0（2.0,3.0）; 14.5 ± 4.1,15.6 ± 3.9,（52.5 ± 26.8） mGy^（-1）,3.0（2.0,3.0）; 34.9 ± 13.3,44.4 ± 12.2,（339.3 ± 237.8） mGy^（-1）,3.0（3.0,4.0） respectively.The data mentioned above for B1-FBP,B2-iDose^4 and B2-IMR were 9.0 ± 2.4,9.7 ± 2.7,（6.0 ± 3.7） mGy^（-1）,3.0（2.0,3.0）; 13.3 ± 3.3,14.9 ±2.9,（22.8 ± 9.3） mGy^（-1）,3.0（2.0,3.0）; 28.4 ± 9.0,38.5 ± 10.3,（157.0 ± 86.9） mGy^（-1）,3.0（3.0,4.0） respectively.The image quality grading difference among Group A1-FBP and A2-iDose^4,Group B1-FBP and Group B2-iDose^4 had no statistical significance（P 0.05）,whereas the data difference for the rest groups had statistical significance（P 0.01）.Conclusion Use of IMR can prominently improve the SNR,CNR and image quality compared to iDose^4.Considering the patient＇s BMI,by applying appropriate low tube voltage（80 k V or 100 k V） combined with IMR,the optimal image can be obtained while reducing the radiation dose.
出处
《临床放射学杂志》
CSCD
北大核心
2017年第4期566-570,共5页
Journal of Clinical Radiology
基金
苏州市科技发展计划指导项目(编号:SYSD2016088)
