Application of the Low-dose One-stop-shop Cardiac CT Protocol with Third-generation Dual-source CT / 中国医学科学院学报

Objective To evaluate the feasibility of a low-dose one-stop-shop cardiac CT imaging protocol with third-generation dual-source CT (DSCT). Methods Totally 23 coronary artery disease (CAD) patients were prospectively enrolled between March to September in 2016. All patients underwent an ATP stress dynamic myocardial perfusion imaging (MPI) (data acquired prospectively ECG-triggered during end systole by table shuttle mode in 32 seconds) at 70 kV combined with prospectively ECG-triggered high-pitch coronary artery angiography (CCTA) on a third-generation DSCT system. Myocardial blood flow (MBF) was quantified and compared between perfusion normal and abnormal myocardial segments based on AHA-17-segment model. CCTA images were evaluated qualitatively based on SCCT-18-segment model and the effective dose(ED) was calculated. In patients with subsequent catheter coronary angiography (CCA) as reference,the diagnosis performance of MPI (for per-vessel ≥50% and ≥70% stenosis) and CCTA (for≥50% stenosis) were assessed. Results Of 23 patients who had completed the examination of ATP stress MPI plus CCTA,12 patients received follow-up CCA. At ATP stress MPI,77 segments (19.7%) in 13 patients (56.5%) had perfusion abnormalities. The MBF values of hypo-perfused myocardial segments decreased significantly compared with normal segments [(93±22)ml/(100 ml·min) vs. (147±27)ml/(100 ml·min);t=15.978,P=0.000]. At CCTA,93.9% (308/328) of the coronary segments had diagnostic image quality. With CCA as the reference standard,the per-vessel and per-segment sensitivity,specificity,and accuracy of CCTA for stenosis≥50% were 94.1%,93.5%,and 93.7% and 90.9%,97.8%,and 96.8%,and the per-vessel sensitivity,specificity and accuracy of ATP stress MPI for stenosis≥50% and ≥70% were 68.7%,100%,and 89.5% and 91.7%,100%,and 97.9%. The total ED of MPI and CCTA was (3.9±1.3) mSv [MPI:(3.5±1.2) mSv,CCTA:(0.3±0.1) mSv]. Conclusion The third-generation DSCT stress dynamic MPI at 70 kV combined with prospectively ECG-triggered high-pitch CCTA is a feasible and reliable tool for clinical diagnosis,with remarkably reduced radiation dose.

Application of 70 kV Third-generation High-pitch Dual-source Coronary CT Angiography in Patients with Different Body Mass Index / 中国医学科学院学报

Objective 　To investigate the optimized range of body mass index (BMI) selection for patients undergoing 70 kV high-pitch dual-source coronary CT angiography (CCTA) on the third-generation dual-source CT (DSCT). Methods 　Patients undergoing prospective high-pitch ultra-low contrast media (CM) CCTA on the third-generation DSCT using the automatic tube voltage selection at 70 kV were included and divided into three groups:group A,with BMI≤24 kg/m;group B,with 24 kg/m<BMI<28 kg/m;and group C,with BMI≥28 kg/m. The baseline data,image quality results,and effective dose (ED) were evaluated and compared. Results 　No significant difference was found in age (H=2.36,P=0.78),heart rate (H=3.51,P=0.80),and ED(H=1.77,P=0.12) among three groups. The noise of the aortic root in group A was (21.66±4.00)HU,which was significantly lower than that in group C [(23.61±4.20)HU](F=2.05,P=0.03). The signal to noise ratio of aortic root in group A (18.61±5.28) was significantly better than that in group C (14.75±2.58) (F=5.31,P=0.02). No other significant difference in quantitative image quality were found among the three groups (all P >0.05). Subjective image quality in group A(Z=2.91,P=0.004) and B(Z=2.27,P=0.021) were both significantly better than that in group C. Conclusion 　The ultra-low tube voltage (70 kV) combined with ultra-low CM CCTA protocol on third-generation high-pitch DSCT may be better for patients with BMI<28 kg/m2 than those with BMI ≥28 kg/min China.

Initial Experience of the Application of Automated Tube Potential Selection Technique in High-pitch Dual-source CT Angiography of Whole Aorta Using Third-generation Dual-source CT Scanner / 中国医学科学院学报

Objective To evaluate the application of automated tube potential selection technique in high-pitch dual-source CT aortic angiography on a third-generation dual-source CT scanner. Methods Whole aorta angiography were indiated in 59 patients,who were divided into 2 groups using a simple random method:in group 1 there were 31 patients who underwent the examination with automated tube potential selection using a vascular setting with a preferred image quality of 288 mA/100 kV;in group 2 there were 28 patients who underwent the examination with a tube voltage of 100 kV and automated tube current modulation using a reference tube current of 288 mA. Both groups were scanned on a third generation dual-source CT device operated in dual-source high-pitch ECG-gating mode with a pitch of 3.0,collimation of 2×192×0.6 mm,and a rotation time of 0.25 s. Iterative reconstruction algorithm was used. For group 1,the volume and flow of contrast medium and chasing saline were adapted to the tube voltage. For group 2,a contrast material bolus of 45 ml with a flow of 4.5 ml/s followed by a 50 ml saline chaser at 5 ml/s was used. CTA scan was automatically started using a bolus tracking technique at the level of the original part of aorta after a trigger threshold of 100 HU was reached. The start delay was set to 6 s in both groups. Effective dose (ED),signal to noise ratio (SNR),contrast to noise ratio (CNR),and subjective diagnostic quality of both groups were evaluated. Results The mean ED were 21.3% lower (t=-3.099,P=0.000) in group 1 [(2.48±0.80) mSv] than in group 2 [(3.15±0.86) mSv]. Two groups showed no significant difference in attenuation,SD,SNR,or CNR at all evaluational parts of aorta (ascending aorta,aortic arch,diaphragmatic aorta,or iliac bifurcation)(all P>0.05). There was no significant difference in subjective diagnostic quality values of two groups [(1.41±0.50) scores vs. (1.39±0.50) scores;W=828.5,P=0.837]. Conclusion Compared with automated tube current modulation,the automated tube potential selection technique in aorta CT angiography on a third-generation dual-source CT can dramatically reduce radiation dose without affecting image quality.

Initial Experience of the Application of Third-generation Dual-source CT Scanner in High-pitch Angiography of Aorta / 中国医学科学院学报

Objective To evaluate the value of third-generation dual-source CT scanner in application of high-pitch aorta CT angiography(CTA). Methods Totally 59 patients clinically indicated for whole aorta angiography were divided into 2 groups using a simple random method:in group 1 there were 28 patients who underwent the examination on a third-generation dual-source CT device,with a collimation of 2×192×0.6 mm and a rotation time of 0.25 s;in group 2 there were 31 patients who underwent the examination on a second generation dual-source CT device,with a collimation of 2×128×0.6 mm and a rotation time of 0.28 s. Both groups were given the examination operated in dual-source high-pitch ECG-gating mode with a pitch of 3.0,a tube voltage of 100 kV,and automated tube current modulation using a reference tube current of 288 mA. A contrast material bolus of 45 ml with a flow of 4.5 ml/s followed by a 50 ml saline chaser in 5.0 ml/s was used. CTA scan was automatically started using a bolus tracking technique at the level of the original part of aorta after a trigger threshold of 100 HU was reached. The start delay was set to 6 s in both groups. Effective dose(ED),signal to noise ratio (SNR),contrast to noise ratio (CNR),and subjective diagnostic quality of both groups were evaluated. Results The mean ED were 19.44% lower (t=-3.989,P=0.000) in group 1 [(3.15±0.86)mSv] than in group 2 [(3.91±0.60)mSv]. These two groups showed no significant differences in SNR or CNR (all P >0.05). The subjective diagnostic quality values also showed no significant difference between two groups [(1.39±0.50)scores vs. (1.45±0.51)scores;W=814.5,P=0.651].Conclusion Compared with the second-generation dual-source CT scanner,the third-generation dual-source CT scanner in whole aorta CTA can remarkably reduce the radiation dose without affecting image quality.

The impact of heart rate on image quality and reconstruction timing of dual-source CT coronary angiography / 中华放射学杂志

ObjectiveTo evaluate the impact of patient's heart rate(HR)on coronary CT angiography(CTA)image quality(IQ)and reconstruction timing in dual-source CT(DSCT).Methods Ninety-five patients with suspicion of coronary artery disease were examined with a DSCT scanner(Somatom Definition.Siemens)using 32×0.6 mm collimation.All patients were divided three groups according to the heart rate(HR):group 1,HR≤70 beats per minute(bpm),n=26;group 2,HR＞70 bpm to≤90 bpm, n=37;group 3,HR＞90 bpm,n=32. No beta-blockers were taken before CT scan.50-60 ml of nonionic contrast agent were injected with a rate of 5 ml/s. Images were reconstructed from 10%to 100% of the R-R interval using single-segment reconstruction. Two readers independently assessed IQ of all coronary segments using a 3-point scale from excellent(1)to non-assessable(3)for coronary segments and the relationshiD between IQ and the HR. ResuitsOverall mean IQ score was 1.31 ±0.55 for all patients with 1.08±0.27 for group 1,1.32±0.58 for group 2 and 1.47±0.61 for group 3. The IQ was better in the LAD than the RCA and LCX(P＜0.01).Only 1.4%(19/1386)of coronary artery segments were considered non-assessable due to the motion artifacts.Optimal image quality of all coronary segments in 74 patients(77.9%)can be achieved with one reconstruction data set.The best IQ was predominately in diastote(88.5%)in group 1,while the best IQ was in systole(84.4%)in group 3. ConclusionsDSCT can achieve the optimal IQ with a wide range of HR using single-segment reconstruction. With the increasing of HR,the timing of data reconstruction for the best IQ shifts from mid-diastole to systole.

Dual-source CT coronary angiography in patients with premature heart-beats:initial experience / 中华放射学杂志

Objective To evaluate the feasibility of dual-source computed tomography(DSCT)coronary angiography in a population with premature heart-beats.Methods Seventy patients with suspected coronary artery disease and premature heart-beats were routinely imaged on a DSCT scanner(Somatom Definition,Siemens AG,Germany).The images were reconstructed before and after ECG editing.Two readers independently assessed image quality of all coronary segments using a four-point grading scale from excellent(1)to non-assessable(4).The results ofthe two groups were compared with a paired t-test,and a P value of less than 0.05 Was considered significant.Results The mean heart rate during examination ranged from 49 to 111 bpm[mean(70.7±12.4)bpm].Twenty-eight of 70 patients with relatively small variability of the heart rate[(41.0±18.4)bpm]got diagnostic image quality without ECG editing.In other 42 patients with larger variability of the heart rate[(71.4±28.7)bpm],the meal image quality scores were 2.09±1.27 and 1.50±0.79 before and after ECG editing,there Was a significant difference(t=13.764,P＜0.01).The proportion of non-assessable segments Was reduced from 24.8%(154/620)to 3.4%(21/620)through ECG editing(X2=121.846,P＜0.01).Finally,the diagnostic image accounted 98.0%(1014/1035)in all segments of 70 patients.Conclusion DSCT can provide diagnostic images for patients with premature heart-beats.The image quality in patients with larger variability of the heart rate can be significantly improved through ECG editing.

Coronary Artery Imaging in Patients with High Heart Rate by Dual-source CT:The Initial Experience / 实用放射学杂志

Objective To explore the scanning technique and image quality of coronary artery imaging with dual-source CT without oral Betaloc preparation in the patients with high heart rate.Methods 412 cases were undergone coronary imaging with dual-source CT (including plain and enhanced scans) ,among them,there were 30 cases with heart rate more than 100 bpm.Multi-planar reconstruction(MPR),maximum intensity projection(MIP) and volume rendering (VR) were performed using contrast-enhanced images.The image quality was classified into 3 grades, and coronary segments named according to AHA standard were evaluated.Results The average heart rate during enhanced scan in the 30 cases was (115.6?11.8)(101～139)bpm,the average breath hold time was (5.7?1.2) s.The best reconstruction phase was in the systolic phase. Altogether 424 coronary segments were evaluated, among them 93.9%(398/424)belonged to the first grade,5.0%(21/424)belonged to the second grade,and 1.2%(5/424) belonged to the third grade. Conclusion Without oral administration of Betaloc preparation, good coronary artery images can be obtained in the patients with high heart rate by dual-source CT.