Applied Research On Double Low Scanning Technique In Gem Spectrum CT Coronary Artery Angiography

Objective:To investigate the feasibility of double low scanning technique using the gem spectrum CT coronary artery angiography among the patients at low heart rate ≤ 65 beats / min,measured and analyzed objectively index CNR, SNR and noise, and subjective image quality scores, To explore the feasibility of low-dose radiation scanning technology and low-dose contrast medium used in gemstone spectrum CT coronary artery angiography.Methods: This prospective study was approved by the institutional review board with patient informed consent. Ninty patients(heart rate ≤65 bpm) were randomly devided into 3 groups, 49 man and 41 women,aged 36 to 77.Group A underwent spectral CCTA with iodixanol(Visipaque,270mg/ml)and low scanning technique, Group B conventional CCTA with iodixanol(Omnipaque, 370mg/ml) and Group C conventional CCTA with iodixanol(Visipaque, 270mg/ml),Routine scan mode was used in Group B and Group C. Prospective ECG gating mode was used in all groups. The total amount of contrast agent was0.8ml/Kg,injection rate was 5.5ml/s, 120 k Vp polychromatic images with FBP algorithm(Group B and Group C) were reconstructed for conventional CCTA, 60 ke V monochromatic images with FBP algorithm(Group A) or with a fixed blending level(40%) of ASi R(Group A1) were reconstructed for spectral CCTA.Compared image quality of four groups and ED in three groups.Results: The difference was ststistically significant between four groups with the CT value, image noise, SNR and CNR of coronary(each P<0.001. Group A1 has the highest SNR and CNR.Group C has the lowest image noise.There were no significant difference of coronary score between group A1 and group B(χ2=0.01, P=1.000)). There was significant difference of coronary score between group A and group B(χ2=22.428, P <0.001), group B and group C(χ2=39.005, P <0.001), group A1 and group A(χ2=21.854, P<0.001). Effective radiation dose in the group A(ED2.60±0.26 m Sv) was lower than that of group B(ED3.02±0.36 m Sv)(t=3.738, P=0.001)and group C(ED3.11±0.23)(t=3.725, P=0.001).Conclusion: Double low scanning technique using the gem spectrum CT coronary artery angiography with40% blending level of ASi R is able to provide better image quality than using conventional CCTA and to reduce the effective radiation dose and contrast dose.