Applications Of Low Concentrations Of Contrast Medium In The Coronary CT Angiography

ObjectiveTo investigate the value of low concentrations, low dose of contrast agents andlow radiation dose combined with sinogram-affirmed iterative reconstruction(SAFIRE) improving coronary artery image quality and reducing radiation dose andthe incidence rate of contrast medium induced nephropathy in second-generationdual-source CT Sequence or Flash scan mode of coronary artery imaging.MethodsThis thesis was divided into2parts.Part1: Forty-two patients with coronary artery disease were randomly dividedinto group A (370mgI/ml120kV) and group B (270mgI/ml100kV), which were allscaned in Sequence scan mode. The images of group B were reconstructed withSAFIRE and taken as group C.The general information, scan time, the dose ofcontrast agent, the effective radiation dose and coronary artery segment image qualityof group A and group B(C) were compared. The coronary CT value and imagenoise(SD) were measured and compared in aorta, left coronary and right coronary,then the SNR and CNR among three groups were calculated and compared. Part2: sixty-six patients with coronary artery disease were randomly dividedinto group A(370mgI/ml,60ml)、group B(370mgI/ml,(weight×0.6)ml) and group C（320mgI/ml,(weight×0.6)ml,SAFIRE）,which were all scaned in Flash spiral scanmode. The difference of image quality were compared among3groups;Thedifference of coronary CT value, SD, SNR and CNR were measured and compared inaorta, left coronary and right coronary.ResultsPart1: There were not statistically significant in age, BMI, average heart rate,scan time and contrast dosage of group A and group B(C)(all P>0.05), while the ED,CTDIvol and the coronary artery segment image quality had statistically significant(all P<0.05). The coronary CT values in aorta,left coronary and right coronary amongthree groups were all not statistically significant (all P>0.05), while the noise, SNR,CNR had statistically significant (all P<0.05). The image noise was the highest andSNR, CNR were the lowest in group B, and there were not statistically significant innoise, SNR and CNR between group A and group C.The effective dose was (2.47±0.63) mSv in group B(C), and (4.14±1.17) mSv in group A, which had significantdifference(t=5.759, P <0.05).Part2: There were not statistically significant in age, BMI, average heart rate,scan time, image quality and coronary CT values among3groups (P>0.05), while thedifferences of image noise, SNR, CNR of three groups were statistically significant(all P<0.05). The image noise was lowest and SNR, CNR were highest in group C.Conclusion1. In Sequence scan mode, the270concentration of contrast agent and low tubevoltage combined with SAFIRE technology can get better image quality and lowerradiation dose in DSCT coronary angiography.2. In Flash spiral scan mode, low dose and low concentration of contrast agentcombined with SAFIRE technology can get better image quality and make theoccurrence of contrast media induced nephropathy lower.