The Feasible Of Using Low Concentrations In Head And Neck CTA Of Dual-source CT

ObjectiveThrough analyse the date of weight and overweight people who injected different concentration contrast medium, we hope providing theoretical support for clinical apply low concentration contrast medium in CTAMethodsAccording to the standard of experiment, choose continuously 59 people who need the head and neck CTA examination divide into 3 groups in completely random:group A (N=20, normal BMI,370mgI/ml); group B (N=20, normal BMI,300mgI/ml); group C (N=19:overweight BMI,300mgI/ml).Using SOMATOM Definition Flash dual-source CT. The scanning range is from the aortic arch to the cranial vault. Directly the enhancement dual-energy scan mode after the position location scan. And apply binoculars high-pressure syringe to inject 60ml non-ionic contrast agent and 40ml saline with 4.5ml/s through the right anterior cubital vein. The scanning triggered by bolus-tracking mode, and the trigger point set at the aortic arch with the threshold of 100 HU, delay 10s to start auto scanning. Scanning direction is from the foot to cephalic. The scanning time is 5-7s.Concrete parameters and:collimation 64×0.6mm, matrix:512×512, slice of automatically rebuilt:0.6mm, Layer spacing:0.5mm, scanning pitch:0.7, tube rotation time:0.5 s/rotation. Meanwhile application CARE Dose 4D. Using many post-processing, such as MIP (maximum intensity projection), VR(volume rendering) In the post-processing workstation (Syngo Multimodality Workplace).Measuring the CT value of the aortic arch, the basilar artery, left and right external carotid artery (the beginning part), left and right internal carotid artery (initial segment), left and right siphon section, left and right anterior cerebral artery A2 segment, left and right middle cerebral artery M1 segment, left and right posterior cerebral artery P1 segment, then calculate the SNR (Signal-to-Noise Ratio), noise ratio (Contrast-to-Noise Ratio). Two physicians evaluate the image of overall, the aortic arch, the basilar artery, left and right external carotid artery (the beginning part), left and right internal carotid artery (initial segment), left and right siphon section, left and right anterior cerebral artery A2 segment, left and right middle cerebral artery M1 segment, posterior cerebral artery P1 segment and superior vena cava-subclavian vein artifacts, count and analyse the evaluation.Result1. The CT value of the aortic arch, the basilar artery, left and right external carotid artery (the beginning part), left and right internal carotid artery (initial segment), left and right siphon section, left and right anterior cerebral artery A2 segment, left and right middle cerebral artery M1 segment, posterior cerebral artery P1 segment has statistical difference between group A, group B and group C (P<0.05); but SNR, CNR of each vessel do not has significant difference between group A, group B and group C (P>0.05).2. the subjective evaluate of overall image, the aortic arch, the basilar artery, left and right external carotid artery (the beginning part), left and right internal carotid artery (initial segment), left and right siphon section, left and right anterior cerebral artery A2 segment, left and right middle cerebral artery M1 segment, posterior cerebral artery P1 segment do not has statistical difference between group A, group B, group C (P>0.05);3. The superior vena cava-subclavian vein artifacts do not has statistical difference between group A, group B, group C (P>0.05).ConclusionThe study found that normal weight and overweight people who take the head and neck CTA of dual-source CT inject 300mgI/ml contrast agent is feasible, the image meet the requirements for diagnosis.So that decline the damage of renal.