A Study of the Application of Iterative Model Reconstruction Combined with Low Tube Voltage MSCT in Renal Artery CT Angiography
Author(s): ZUO Xin, GONG Jianping, ZHANG Wei, CAI Wu, CHEN Guangqiang, ZHU Jianbing, QIAO Fang
Pages: 566-570
Year: 2017 Issue: 4
Journal: Journal of Clinical Radiology
Keyword: Renal artery; Imaging processing; computer assisted; Tomography; X-ray computed; Radiation dosage;
Abstract: 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).Methods 120 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/m2) and Group B (22 kg/m2 ＜ BMI ≤ 25 kg/m2) according to the patient 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 kV,FBP;Group A2-iDose4 (80kV,iDose4);Group A2-IMR (80 kV,IMR) and Group B1-FBP ((120 kV,FBP);Group B2-iDose4 (100kV,iDose4);Group B2-IMR (100 kV,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 A1&A2,B1&B2 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-iDose4 and A2-IMR;B1-FBP,B2-iDose4 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 16.9mGy,(886.1 ± 46.0) mGy · cm,(13.3 ±0.7) mSv;4.9mGy,(261.9 ±12.5) mGy · cm,(3.9 ±0.2) mSv respectively.The data mentioned above for Group B1 and Group B2 were 16.9mGy and (929.6 ±45.3) mGy · cm,(14.0 ±0.7) mSv;10.1mGy、(559.9 ±26.4) mGy · cm and (8.4 ± 0.4) mSv 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-iDose4 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-iDose4 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-iDose4,Group B1-FBP and Group B2-iDose4 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 iDose4.Considering the patient's BMI,by applying appropriate low tube voltage(80 kV or 100 kV) combined with IMR,the optimal image can be obtained while reducing the radiation dose.
Pages: 566-570
Year: 2017 Issue: 4
Journal: Journal of Clinical Radiology
Keyword: Renal artery; Imaging processing; computer assisted; Tomography; X-ray computed; Radiation dosage;
Abstract: 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).Methods 120 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/m2) and Group B (22 kg/m2 ＜ BMI ≤ 25 kg/m2) according to the patient 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 kV,FBP;Group A2-iDose4 (80kV,iDose4);Group A2-IMR (80 kV,IMR) and Group B1-FBP ((120 kV,FBP);Group B2-iDose4 (100kV,iDose4);Group B2-IMR (100 kV,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 A1&A2,B1&B2 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-iDose4 and A2-IMR;B1-FBP,B2-iDose4 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 16.9mGy,(886.1 ± 46.0) mGy · cm,(13.3 ±0.7) mSv;4.9mGy,(261.9 ±12.5) mGy · cm,(3.9 ±0.2) mSv respectively.The data mentioned above for Group B1 and Group B2 were 16.9mGy and (929.6 ±45.3) mGy · cm,(14.0 ±0.7) mSv;10.1mGy、(559.9 ±26.4) mGy · cm and (8.4 ± 0.4) mSv 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-iDose4 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-iDose4 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-iDose4,Group B1-FBP and Group B2-iDose4 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 iDose4.Considering the patient's BMI,by applying appropriate low tube voltage(80 kV or 100 kV) combined with IMR,the optimal image can be obtained while reducing the radiation dose.
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