Dual Source Double-low Dose CTA With Iso-osmolar Contrast Material For Craniocervical Arteries

Objective: To evaluate the image quality and radiation dose of head and neck CT angiography(CTA)using low tube voltage and low volume of isotonic contrast material.Methods: A total of eighty patients who underwent head and neck CTA were randomly assigned into 2 groups: group A(double low-dose group,40 cases)with 80/Sn140 k Vp,sinogram-affirmed iterative reconstruction(SAFIRE)and 32 ml of 270 mg I/ml contrast material,and group B(conventional group,40 cases)with 100/Sn140 k Vp,filtered back-projection reconstruction(FBP)and 40 ml of 370 mg I/ml contrast material.Attenuation values were measured from the center of specific arterial segments using regions of interest.The CT attenuation,effective dose(ED),image noise,signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)of each arterial segment were compared between the two protocols using the Student t test.Qualitativeanalysis between both protocols was performed.Results: Both groups of CTA achieved comparable CT attenuation,image noise,SNR and CNR in each arterial segments(P >0.05),except for the image noise of ascending aorta(P< 0.01).Using the double low-dose mode,the ED was reduced by about 23.8 %(t=-8.295,P(27)0.001),and iodine intake of patients in group A was reduced by 41.6%(8.6g versus 14.8g).There was no significant difference in image quality between the two groups(t=-0.777,P>0.05).The consistency between the two observers was good(kappa value = 0.626,P(27)0.001).Conclusion: In head and neck 3dual-source CTA,using low tube voltage and low volume of isotonic contrast material not only provided images of diagnostic quality but also reduced both radiation dose and iodine intake during scanning.Background: To compare the image quality,radiation dose and iodine load of cervico-cerebral CTA in the same group of patients.Materials and Method: A retrospective study was performed in 18 patients of head and neck CTA using different protocols in interval of time.All patients first underwent conventional cervico-cerebral CTA examination(group B),with tube voltage of 100/140 Sn k Vp,as well as low-osmolar contrast media(CM)370mg I/ml,with volume of 40 ml and injection rate of 5ml/s.After a period of time,the same group of patients accepted a second cervico-cerebral CTA(group A),for which a personalized protocol was selected,with tube voltage of 80/140 Sn k Vp,as well as isotonic-osmolar CM 270 mg I/ml,with different volume of 20-42 ml and injection rate of 4.0-6ml/s,according to the dynamic curve of test bolus injection.The CT attenuation,effective dose(ED),image noise,signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)of each arterial segment were compared between the two protocols using the MannWhitney U test.Qualitative analysis between the protocols was also performed.Result: The CT values of arterial segments of protocol A were lower than protocol B,but the difference was no statistically significant(P>0.05)except for the proximal segment of middle cerebral artery(M1)(P<0.05).Conclusion: Head and neck CTA examinations with 128-section dual energy CTA may be performed using a protocol that combines low dose of contrast material and low dose of radiation,which can provide satisfactory image quality for clinical application.The use of low dose CM volume in different protocol may reduce contrast-induced nephropathy.