Application Value Of Dual-source CT With Low Tube Voltage And Low Concentration Contrast Agent In Head And Neck CT Angiography

Objective:To explore the feasibility and value of the second generation dual-source CT angiography(CTA)with low tube current,low iodine concentration and low dose contrast agent combined with large screw length and automatic tube current modulation(Care Dose4D)iterative reconstruction algorithm in clinical application,and to evaluate the image quality,radiation dose and effective iodine consumption.Methods:Sixty patients with head and neck CTA with dual-source CT were selected from the Department of Imaging of the Fifth Affiliated Hospital of Xinjiang Medical University from January2020 to October 2020.According to different examination methods,they were randomly divided into conventional group and double-low-dose group.The routine group was scanned with 100/SN140 KVP contrast agent concentration of ioprolamide(370mg(I)/ml),contrast agent dosage of 40 ml,normal saline of 30 ml,injection rate of 5ml/s,pitch of 0.810.Patients in the dual low-dose group(low tube voltage,low iodine intake)were treated with 80/SN140 KVP and iodmepropor(320mg(I)/m L of contrast agent,30 m L of normal saline,injection rate of 5m L/s,pitch of 1.390,and iterative reconstruction algorithm.The subjective and objective image quality of the head and neck arteries in the conventional and double-low-dose groups were retrospectively evaluated by double-blind method,and the radiation dose and effective iodine consumption between the two scanning regiments were compared.Results: Mann-Whitneyu nonparametric rank sum test was used to compare the differences between the conventional group and the double low-dose subjective scores.The consistency of the subjective scores of image quality in the two groups was evaluated by Kappa value.The scores of image quality in the two groups were all over 3 points,and there was no statistically significant difference in the subjective scores of image quality between the two groups(Z=-0.869,P=0.385).The two groups of observers had a high consistency in their image quality scores(Kappa-0.648 in the conventional group and Kappa-0.675 in the double-low group;The independent sample t test was used for objective evaluation,including arterial CT value,image background noise,signal-to-noise ratio(SNR),contrastive noise ratio(CNR),volume CT dose index(CTDIvol),dose length product(DLP)and effective dose(ED)of the two groups.The CT attenuation value of the double-low-dose group was also significantly higher than that of the conventional group(P<0.001).In addition,CTDivol,DLP,effective dose ED and iodine consumption were reduced by 53%,49.4%,and 36%(P<0.001)in the dual-low-dose group compared to the conventional regimen given 140 k VP and370 mg I/d L(P<0.001).The radiation dose and iodine intake were significantly reduced in the dual-low-dose group.The image quality of the two groups was significantly improved in subjective evaluation and objective evaluation.Conclusion: In the scanning scheme of low tube voltage,low iodine concentration and low dose contrast agent combined with large pitch and automatic tube current modulation and iterative reconstruction algorithm,the risk associated with radiometric contrast nephropathy can be significantly reduced without reducing objective index analysis and subjective score,and the full diagnostic quality of head and neck CTA can be obtained.This method can be widely used in other parts of the body and has good clinical application value,in order to guide clinical practice.