| Part IThe application of using low tube voltage technique scan on Coronary Artery Angiography with Dual-Source CTObjective(1) To analysis the image quality of using80kVp tube voltage scan protocol with Dual-source CT coronary angiography and to explore the application of using80kVp tube voltage scan protocol for reducing radiation dose.(2) To explore the value of using intelligent optimal kV scanning technology (CARE kV) with Dual-source CT coronary angiography in reducing the radiation dose and its effect on image quality.(3) To investigate the effects of Sinogram Affirmed Iterative Reconstruction (SAFIRE) on application value in coronary dual-source CT angiography comparing with regular filtered back projection (FBP).Materials and Methods(1) Dual-source CT coronary angiography was performed in90consecutive patients with a normal BMI (male:20kg/m2<BMI<25kg/m2, female:19kg/m2<BMI<24kg/m2), Patients were randomized to using80kVp(362mAs),100kVp(362mAs) and120kVp(362mAs)(n=30).The difference between three groups in image quality, mean CT values, images noise, Signal-to-noise ratio, Contrast-to-noise ratio and radiation dose were compared. (2) Dual-source CT coronary angiography was performed in150consecutive patients with a normal BMI. Patients in group A(n=30) underwent120kV scanning with CARE kV(semi) combined CARE Dose4D techniques(Ref. kV=120,Quality ref.mAs/rot=400).Patients in group B(n=30) underwent100kV scanning with CARE kV(semi) combined CARE Dose4D techniques(Ref.kV=120, Quality ref.mAs/rot=400).Patients in group C(n=30) underwent80kV scanning with CARE kV(semi) combined CARE Dose4D techniques(Ref. kV=120,Quality ref.mAs/rot=400).Patients in group D(n=30) underwent scanning with CARE kV(On) combined CARE Dose4D techniques(Ref. kV=120, Quality ref.mAs/rot=400). Patients in group E(n=30) underwent scanning with CARE kV(On) combined CARE Dose4D techniques (Ref.kV=100, Quality ref.mAs/rot=400).The difference between five groups in image quality, mean CT values, images noise, Signal-to-noise ratio, Contrast-to-noise ratio and radiation dose were compared.(3) Dual-source CT coronary angiography was performed in80consecutive patients with a overweight BMI (male:25kg/m2<BMI<30kg/m2,female:24kg/m2<BMI<29kg/m2). Patients were randomized to using120kVp (group A, n=40) and100kVp (group B, n=40) with FBP, while the images of group B were rebuilt with SAFIRE and taken as group C. The difference between three groups in image quality, mean CT values, images noise, Signal-to-noise ratio, Contrast-to-noise ratio and radiation dose were compared.Results(1) The mean image quality scores in patients scanned with three groups were (3.50±0.61),(3.43±0.53) and (3.29±0.82), there was no statistical difference between the three groups (P>0.05). The mean CT value in80kVp group was higher than100kVp group and120kVp, which the difference was statistically significant between two groups (P<0.05). The image noise in80kVp group was higher than100kVp group and120kVp, which the difference was statistically significant between two groups (P<0.05). And the SNR and CNR was no statistic difference between the three groups (P>0.05). The effective radiation dose was (10.39±1.35) mSv for120kVp group,(7.29±1.36mSv) for100kVp group and (2.80±1.53) mSv for80kVp group, which the difference was statistically significant between two groups (P<0.05).(2) The mean image quality scores in patients scanned with five groups were (3.42±0.63),(3.41±0.54),(3.49±0.33),(3.45±0.43) and (3.48±0.81), there was no statistical difference between the three groups (P>0.05).The mean CT value and image noise in group C was higher than other groups, which the difference was statistically significant between two groups (P<0.05). And the SNR and CNR was no statistic difference between the five groups (P>0.05). The effective radiation dose in group C was lower than other groups, which the difference was statistically significant between two groups (P<0.05).(3) The mean image quality scores in patients scanned with three groups were (3.51±0.70),(3.49±0.33) and (3.55±0.47), there was no statistical difference between the three groups (P>0.05). The difference of the mean CT value, image noises and CNR was statistically significant between three groups (P<0.05). The difference of the mean CT value between group A and group B (or group C) was statistically significant (P<0.05), and group A was lowest. The difference of the image noises and CNR between group A (or group C) and group B was statistically significant (P<0.05), and group A (or group C) was higher. The difference of the effective radiation dose between group A and group B (or group C)was statistically significant (P<0.05), and group B(or group C) decreased radiation dose of about34%than group A.Conclusion(1) Using80kV or100kV tube voltage scan protocol with dual-source CT coronary angiography is feasible in patients with normal BMI. The scan protocol can substantially reduce radiation doses while preserve good diagnostic image quality.(2) Using CARE kV (On) combined CARE Dose4D techniques (Ref. kV=100, Quality ref. mAs/rot=400) with dual-source CT coronary angiography is feasible in patients with normal BMI. The scan protocol can substantially reduce radiation doses while preserve good diagnostic image quality.(3) Using100kV tube voltage and S AFIRE scan protocol with dual-source CT coronary angiography is feasible in patients with overweight BMI. The scan protocol can substantially reduce radiation doses while preserve good diagnostic image quality. Part IIThe application of using low tube voltage technique scan on Coronary Artery Angiography with Dual-Source CTObjective(1) Our study was to evaluate the image quality of using100kVp tube voltage scan protocol with Dual-source CT coronary angiography by three different concentrations of contrast media. To investigate the value of using270mg I/ml iodine Contrast Medium with100kVp tube voltage scan protocol on Dual-source CT coronary angiography.(2) Our study was to evaluate the image quality of using different tube voltage scan protocol with Dual-source CT coronary angiography by three different contrast media injection method. To investigate the value of using low dosage and low rate with low tube voltage scan protocol on Dual-source CT coronary angiography.Materials and Methods(1) Dual-source CT coronary angiography was performed in120consecutive patients were divided into three groups randomly with a normal BMI. Using the370mg I/ml,320mg I/ml and270mg I/ml concentration of contrast medium, with the same injection rate (5ml/s) for enhanced scan. The injection and scanning protocols were the same for three groups. The difference between three groups in mean attenuation and visibility of coronary arteries, mean CT values of ROI, images noise, Signal-to-noise ratio and Contrast-to-noise ratio were compared.(2) Dual-source CT coronary angiography was performed in120consecutive patients were divided into three groups randomly with a normal BMI. Using three different contrast media injection methods with enhanced scan. To evaluation the constructed defect of three groups between precava and the right ventricle. And the difference between three groups in mean attenuation and visibility of coronary arteries, mean CT values of ROI, images noise, Signal-to-noise ratio and Contrast-to-noise ratio were compared.Results(1) The mean attenuation and visibility of4main branches of coronary arteries are100%in three groups, and no significant differences were found in mean attenuation and visibility of other small branches (P>0.05). There was statistical difference were found in the mean CT value of AAO, DAO, LM, LVW, RCA, LAD, LM and LCX among coronary artery of three groups (P<0.05), and the group370was higher, group270was lowest. There was no statistical difference were found in the mean CT value of LVW, image noise, SNR, CNR and (P>0.05). There was statistical difference was found in radiation dose of three groups (P<0.05).(2) The appearance of the constructed defect between precava and the right ventricle with group A obviously higher than group B and C, which the difference was statistically significant (P<0.05). There was no statistical difference were found in the constructed defect between precava and the right ventricle between group B and C(P>0.05).The mean attenuation and visibility of4main branches of coronary arteries are100%in three groups, and no significant differences were found in mean attenuation and visibility of other small branches (P>0.05). There was no statistical difference were found in image noise, SNR and CNR (P>0.05).And there was no statistical difference were found in the mean CT value of LVW,AAO,DAO,LM,RCA,LAD,LM and LCX(P>0.05). There was statistical difference was found in radiation dose of three groups (P<0.05).Conclusion(1) Using270mgI/ml iodine Contrast Medium and100kVp tube voltage scan protocol with dual-source CT coronary angiography can achieve "low radiation dose and low iodine loading dose" while preserve good diagnostic image quality with normal BMI.(2) Using100kV tube voltage combined contrast media injection method with low dosage and low rate scan protocol with dual-source CT coronary angiography is feasible in patients with normal BMI. The scan protocol can substantially reduce radiation doses while preserve good diagnostic image quality. |
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