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Objective To explore the feasibility of “double low ”(low tube voltage and low contrast agent concentration)imaging technology of dual-source computed tomography (DSCT)in coronary angiography for low-weight patients.Methods 60 patients (BMI≤25 kg/m2 )who underwent coronary CT angiography (CCTA)on DSCT scanner were divided randomly into 2 groups:group A was “double low”group (n = 30,tube voltage = 80 kVp,using sinogram affirmed iterative reconstruction technology and 270 mg I/mL concentration of contrast agent);Group B was conventional group (n=30,tube voltage=120 kVp,using filtered back projection technology and 350 mg I/mL concentration of contrast agent).Adaptive cardiosequence prospective ECG-gated technology (CorAdSeq)was applied in both the groups,The collecting phase was 65%-75% RR interval (when heart rate<70 beats per mi-nute)or 40%-50% RR interval (when heart rate≥70 beats per minute).Subjective and objective methods were applied to evaluate the image quality.The image quality and.radiation dose were compared between the “double low”group and the conventional group by using SPSS 1 9.0 software.The differences between measurement data were analyzed by using independent samples t-test.Results The effective dose with size specific dose estimates (EDssde)of group A(1.22±0.31)mGy/cm was significantly lower than that of group B (3.44±0.80)mGy/cm with P <0.001.Contrast-noise ratio,signal-noise ratio and CT value of group A were signifi-cantly higher than those of group B (all P <0.05 ).Conclusion Compared with conventional DSCT coronary angiography,“double low”DSCT coronary scanning proposal for low-weight patients can significantly reduce the radiation dose and the amount of contrast agent,and the image quality can meet the needs of clinical diagnosis.
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Objective To explore the image quality and radiation dose for coronary angiography using DSCT (dual-source computed tomography) under lower tube voltage and lower contrast agent concentration ('double low').Methods A total of 160 patients with suspected coronary artery disease underwent dual-source CCTA.80 patients (BMI ＜ 25 kg/m2) were randomly assigned to group A (270 mg I/ml-80 kV) and B (350 mg I/ml-120 kV).The other 80 patients (25 ≤ BMI ＜30 kg/m2) were randomly assigned to group C (270 mg I/ml-100 kV) and D (350 mg I/ml-120 kV),sonogram affirmed iterative reconstruction technology and 270 mg I/ml contrast agent were applied to group A and C ; FBP technology and 350 mg I/ml contrast agent were applied to group B and D.Adaptive cardio-sequence prospective ECG-gated technology was applied in all patients,while the acquisition phase was 65％-75％ RR interval (when heart rate ＜ 75 beats / min) or 40％-50％ RR interval at when heart rate ≥ 75 beats/min.Volume CT dose index (CTDIvol),dose length product (DLP),effective dose (E),size specific dose estimates (SSDE),image noise,CT value,signal-to-noise ratio (SNR),and contrast-to-noise ratio(CNR) were all evaluated for each patient.Results There was not statistical difference in scan length among groups A and B,C and D.There was statistical difference in tube current between group A and B (t =8.932,P ＜0.05).There was not statistical difference in tube current between group C and D (tCD =-1.212,P ＞ 0.05).There was statistical difference in CTDIvol,DLP,E and SSDE between group A and B,C and D (tCTDIvol =-16.141,-11.440 ; tDLP =-17.454,-10.521 ; t =-17.444,-10.523 ;tSSDE =-13.032,-9.119,P ＜0.05).Compared to group B,the SSDE in group A decreased by 64.4％.Compared to group D,the SSDE in group C decreased by 39.3％.There was no statistical difference in image noise between group A and B,C and D (P ＞ 0.05).There was statistical difference in CT value,SNR and CNR between group A and B (t =0.436,4.623,3.272,P ＜ 0.05).There was no statistical difference in CT value and CNR between group C and D,while there was statistical difference in SNR between group C and D (t =2.981,P ＜0.05).There was no statistical difference in image quality scores between group A and B,C and D (P ＞ 0.05).Conclusion Compared with conventional DSCT coronary angiography,'double low' DSCT coronary scanning solution can significantly reduce the radiation dose and contrast agent,and could provide the effective coronary images which meet the clinical diagnostic needs.
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Objective To compare the iodine intake,image quality and radiation dose of dual-source CT coronary artery angiography between the low concentration isotonic contrast agent with iterative reconstruction technique of sinogram affirmed iterative rEconstruction (SAFIRE) and common concentration contrast agent with filtered back projection (FBP).Methods One hundred patients [58 men,42 women; age:(62± 11)y] were enrolled in this study.Fifty consecutive patients (Group A) were scanned with FBP and common concentration contrast agent and another 50 consecutive patients (Group B) were scanned with low concentration isotonic contrast agent and iterative reconstruction technique.The image quality were assessed by two experienced radiologists with a double blinded fashion in a five score scale.The attenuation of coronary artery,scan time,imaging noise,signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR),radiation dose and iodine intake between these two groups were compared using two sample t test.The observer agreement for image quality was calculated using Kappa statistics.Results All examinations were completed successfully.There was no statistical difference (P＞0.05) between two groups in clinical characteristics and scan parameters.There was no statistical difference for the mean subjective image quality of group A (4.4±0.7) and group B (4.3±0.8) (t=0.924,P＞0.05).The Kappa value between two radiologists was 0.887 (P＜0.01)on image quality.The mean attenuation of coronary artery segments was higher than 300 HU,especially in group A (386.1±51.5) HU,which was slightly higher than the group B (384.1±77.1) HU,but there was no statistical difference (t=0.157,P＞0.05).The SNR and CNR in two groups did not have significant differences (P＞0.05).The total iodine and iodine injection rates were 21.0 g,17.5 g/s in Group A and 16.2 g,13.5 g/s in Group B,respectively.The iodine intake was decreased by 22.9％ in Group B.The effective radiation dose in Group B (1.09±0.19) mSv was significantly (t=20.260,P＜0.01) lower than that in Group A (2.85±0.59) mSv,with the radiation dose reduced by 61.8％.Conclusion Low concentration isotonic contrast agent and iterative reconstruction technique can significantly reduce the radiation dose and iodine intake in CT coronary artery angiography and achieve the same image quality using common concentration contrast agent with FBP.
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Objective To explore the accuracy and radiation dose of the right ventricular analysis with DSCT(dual-source computed tomography)using dual-step prospective ECG trigger.Methods Fortyeight consecutive patients who were suspected or diagnosed with coronary artery disease were examined with DSCT coronary angiography and MRI ventricular analysis.Sequential acquisition and dual-step prospective ECG-trigger were used with 30％-90％ width R-R interval.Full tube current output was adopted at 70％ (HR ≤70 bpm)or 40％ (HR ＞ 70 bpm) R-R interval according to heart rates,while 20％ current output was adopted in other R-R interval.Coronary artery was divided into 16 segments according to the American Heart Association.Image quality of coronary arteries were graded with 4-points scale.The DSCT date was reconstructed with 5％ R-R interval.RVESV,RVEDV and RVEF were evaluated in DSCT and MRI.Results Forty-two cases accomplished DSCT and MRI examination.In 558 evaluated coronary segments,96.42％ could be diagnosed.The average radiation dose was(2.82 ± 0.55)mSy.Paired t-test indicated that the RVESV,RVEDV and RVEF of DSCT and MRI had no statistically significant differences (t =-0.28,0.44 and 1.49,P＞0.05),and the correlation was high (r =0.89,0.89,0.87).Conclusions The two generation DSCT with dual-step prospective ECG-triggered sequential acquisition can be used in coronary angiography and right ventricular function analysis simultaneously,which is high in imaging quality of coronary artery,reliable in right ventricular function analysis,as well as lower in radiation dose.