| Objective: To explore the feasibility of low tube voltage,low iodine concentration volume scanning combined with adaptive iterative dose reduction 3D method in renal artery CTA of standard weight patients.Methods: To collect 140 cases of renal CTA by Toshiba Aquilion One 640-slice volume CT in our hospital from June 2017 to June 2018.The body mass index of each patient ranged from 18.5 to 24.0kg/m2.The140 patients were randomly divided into two groups(Group A and Group B,70 in each group)according to the scanning protocol.Group A underwent volume scanning with a tube voltage of 80 kV and a contrast agent of 270 mg I/ml.Group B underwent spiral scanning with a tube voltage of 120 kV and a contrast agent of 320 mg I/ml.other scanning parameters are the same.Two groups of patients' images were reconstructed by adaptive iterative dose reduction 3D(AIDR 3D)and filter back-projection(FBP),get A-AIDR 3D,A-FBP,B-AIDR 3D,B-FBP four group images.Four groups of images are uploaded to Vitrea Fx image processing workstation and processed by VR,MPR and MIP.Two veteran physicians used double blind method to measure the CT value of bilateral renal artery origin and the same level of erector spine muscle.Standard deviation(SD)of erector spine muscle was calculated as noise.Signal noise ratio(SNR)of renal artery and contrast noise ratio(CNR)of renal artery were calculated by formula,and using subjective assessment score to evaluate the 4 groups of image quality.To compare the radiation dose and iodine dosage of patients in A and B groups,and a questionnaire was developed to assess the incidence of adverse reactionsbased on the American Radiological Society's 2008 revised criteria for allergic reactions to contrast agents..SPSS19.0 software was used to analyze the data.Results: The CT value of renal artery enhancement in A-AIDR 3D group was 388.39±19.21 HU,the CT value of renal artery enhancement in A-FBP group was 372.16 ± 42.29 HU,the CT value of renal artery enhancement in B-AIDR 3D group was 346.13±16.57 HU,the CT value of renal artery enhancement in B-FBP group was 333.05±39.14 HU.The noise of A-AIDR 3D group was14.17 ± 3.65 HU,the noise of A-FBP group was 28.68±4.29 HU,the noise of B-AIDR 3D group was 15.21±3.11 HU,the noise of B-FBP group was 26.24 ± 5.18 HU.The SNR in A-AIDR 3D group was 15.78 +1.27,the SNR of A-FBP group was14.69+1.41,the SNR of B-AIDR 3D group was 16.19±1.33,the SNR of B-FBP group was 15.24 ± 1.69.The CNR in A-AIDR 3D group was15.58±1.79,the CNR of A-FBP group was 15.36±1.50,the CNR of B-AIDR 3D group was 11.79±1.93,the CNR of B-FBP group was 12.04±1.63.The two physicians had good consistency in image quality scores of each group,and the subjective scores of renal artery quality of the four groups were greater than or equal to 3'.The enhancement CT value and contrast-to-noise ratio(CNR)of renal artery in A-AIDR 3D and A-FBP groups were higher than those in B-AIDR 3D and B-FBP groups respectively(P < 0.001).The image noise of A-FBP and B-FBP groups was higher than that of A-AIDR 3D and B-AIDR 3D groups respectively(P<0.01).There was no significant difference in renal artery signal-to-noise ratio(SNR)and subjective score between A-FBP,A-AIDR 3D and B-AIDR 3D and B-FBP groups.The iodine used in group A was lower than that in group B.The radiation dose in group A was about 46% lower than that in group B(P < 0.01).Conclusion: The application of low tube voltage(80kV),low iodine concentration(270mg I/ml)volume scanning combined with AIDR 3D inrenal artery CTA of standard weight patients can obtain images that meet the diagnostic requirements,reduce radiation dose and iodine dosage of patients,This program has the value of clinical promotion. |
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