Exploration the Method of Low Dose Coronary Artery Imaging with Dual-Source CT

Objective: On the premise that the image quality meets the requirements of clinical diagnosis, we explored the methods to reduce the radiation dose of coronary artery imaging with Dual-Source CT (DSCT). Methods: We randomly selected 200 patients with coronary heat disease (BIM 0.05). The average image noise in group A is (41.76 ± 7.98) HU, in group B the average image noise is (43.97 ± 3.88) HU, the dif- ference between the two groups was not statistically significant (P>0.05). The average CTDIvol of group A and B were (20.63 ± 2.24) mGy, (38.11 ± 10.69) mGy, respectively, then P <0.01. The average DLP of group A and B are (235.75 ± 28.64) mGycm and (492.59 ± 125.49) mGycm respectively, then P <0.01, the dif- ference of radiation dose had statistical significance (P<0.05). Conclusions: For coronary artery imaging with DSCT the heart electric pulse (AUTO) regulation technology can meet the diagnostic requirements and effectively reduce the radiation dose.

Application of Dual-Source CT TurboFlash Coarse Pitch Scanning in Coronary Artery Imaging

Objective: To compare and analyze the image quality and radiation dose of three scanning modes of dual-source CT coronary artery retrospectively, and to discuss the application value of TurboFlash coarse pitch scanning mode. Methods: The imaging data of 100 patients who underwent CT coronary angiography (CCTA) using Siemens force CT retrospective gated triggering spiral scan (RES-SPIRAL), adaptive prospective gated triggering sequence scan (SEQ) and prospective coarse pitch scan (TurboFlash) retrospectively was collected. The image quality was evaluated by objective and subjective methods. The effective radiation dose of patients was compared and analyzed, and the indications of the three scanning modes were analyzed. The application value of dual-source CT TurboFlash coarse pitch scanning in coronary artery imaging was evaluated. Results: The results showed that the left main coronary artery, the right coronary artery and their tertiary branches could be clearly displayed in the three groups of images: the left anterior descending branch, the left circumflex branch, and their three-level branches. There was no statistical difference in subjective image quality among the three groups of pictures (P > 0.05). There was no statistical difference in objective evaluation indexes, such as CT value, SNR, CNR and Noise among the three groups (P > 0.05). The patient radiation dose results showed that the effective radiation dose ED of RES-SPIRA scan was (9.22 ± 1.33) mSv. The dose of SEQ was (2.88 ± 2.47) mSv, and the dose of TurboFlash was (0.51 ± 0.16) mSv. There was significant difference in comparison of the three groups (P 0.05). RES-spiral scanning had the highest radiation dose and TurboFlash coarse pitch scanning (TurboFlash) had the lowest radiation dose. Conclusion: TurboFlash coarse pitch scanning is low in dosage, fast in speed and wide in adaptability. It is especially suitable for the elderly, children, coma and other patients who cannot cooperate with breath-holding examination, as well as for the screening and examination of coronary artery diseases in asymptomatic population. Undoubtedly, it is a worthy method of heart coronary artery examination.

Generation of linear and nonlinear waves in numerical wave tank using clustering technique-volume of fluid method

A two-dimensional （2D） numerical model is developed for the wave sim- ulation and propagation in a wave flume. The fluid flow is assumed to be viscous and incompressible, and the Navier-Stokes and continuity equations are used as the governing equations. The standard k-e model is used to model the turbulent flow. The Navier- Stokes equations are discretized using the staggered grid finite difference method and solved by the simplified marker and cell （SMAC） method. Waves are generated and propagated using a piston type wave maker. An open boundary condition is used at the end of the numerical flume. Some standard tests, such as the lid-driven cavity, the constant unidirectional velocity field, the shearing flow, and the dam-break on the dry bed, are performed to valid the model. To demonstrate the capability and accuracy of the present method, the results of generated waves are compared with available wave theories. Finally, the clustering technique （CT） is used for the mesh generation, and the best condition is suggested.

双源螺旋CT与全身骨显像对胸椎骨转移瘤的诊断价值

目的:探讨双源螺旋CT与99Tcm-MDP全身骨显像对胸椎骨转移瘤的诊断价值。资料和方法:回顾性分析临床确诊胸椎骨转移瘤且资料完整的住院患者39例52处胸椎骨转移瘤,分析其双源螺旋CT与99Tcm-MDP全身骨显像检查结果。计算两种检查结果的灵敏度及特异性。结果:双源螺旋CT发现37例患者共42处锥体破坏,其灵敏度(81.6%),双源螺旋CT明确诊断胸椎转移瘤27例,可疑10例;99Tcm-MDP全身骨显像检查发现27例患者共31处椎体放射性异常浓集,其灵敏度(59.2%),全身骨显像明确诊断胸椎转移瘤20例,可疑7例;39例患者全身骨显像发现锥体外多发放射性异常浓集。结论:双源螺旋CT对胸椎骨转移瘤的诊断较99Tcm-MDP全身骨显像具有更高的灵敏度,但多数患者经99Tcm-MDP全身骨显像可获得较为明确的诊断。

Application of Dual-Energy CT Non-Linear Fusion Technology in Improving CTA Image Quality of Renal Cancer

Objective: To explore the significance of dual-energy CT non-linear fusion technique in improving the quality of CTA image of renal cancer. Methods: The CTA images of 100 patients who had been confirmed by pathology as renal cancer were collected and were randomly divided into experimental group and control group with 50 cases respectively. The two groups of patients were treated with iodine concentration of 300 mg/ml and 350 mg/ml non-ionic contrast agent, with a dosage of 1.5 ml/kg and an injection rate of 4 ml/s. The contrast agent intelligently tracking method was adopted bolus. The control group used the conventional CTA scanning, with a reference tube voltage/tube current of 100 kv/ref150 mas. The experimental group adopted the double energy scanning, with ball tube A and ball tube B. The reference tube voltage/tube current was 100 kv/ref250 mas and sn150 kv/ref125 mas respectively. The images of the experimental group were non-linear fused to obtain the Mono+ 55 kev single-energy images. The CT value, SNR contrast ratio of the abdominal aorta, renal artery and tumor tissue of the experimental group images and the 100 KV images and the Mono+ 55 kev images of the control group were compared. The objective evaluation and subjective evaluation of the image quality of the three groups of images was performed. Results: The results showed that the 100 kV images of the experimental group were statistically different from those of the control group (P05) in CT value, SNR and CNR (P 0.05). And there was no statistically significant difference between the non-linear fusion single-energy Mono+ 55 kev images and the control group images in CT value, SNR and CNR (P > 0.05). The subjective evaluation of image quality showed that there was no significant difference between Mono+ 55 kev images and control group images, and the quality of Mono+ 55 kev images was higher than that of experimental group 100 kV images. Conclusion: The dual-energy CT non-linear fusion technique can improve the quality of CTA image in patients with renal cancer, and it is possible to obtain high quality CTA images with low iodine concentration contrast agent.

Significance of an Advanced Image-Based Virtual Monoenergetic Reconstruction of Dual Source Dual-Energy CT Data at Low keV Increases Image Quality for Portal Vein System of Pancreatic Cancer Patients

Purpose: To explore the significance of dual-source computed tomography (DECT) virtual monoenergetic reconstructions technology in improving image quality for portal vein system of pancreatic cancer patients. Materials and methods: 47 patients with clinically suspected pancreatic cancer (all confirmed by pathology) were collected. Routine plain scan was performed with Siemens Force dual-source dual-energy CT followed by 3 scans respectively carried out in arterial phase, portal phase and delayed phase. Traditional virtual monoenergetic reconstructions (Mono_E) and new generation of virtual monoenergetic reconstructions (Mono+) were respectively performed on portal vein images to obtain virtual single energy images including Mono_ E70 keV, Mono_E 55 keV and Mono+ 70 keV and Mono+ 55 keV. The signal-to-noise ratio (SNR) and noise of portal vein, normal pancreatic tissues and pancreatic lesions of 100 kV, Mono_E and Mono+ images were compared. In addition, the contrast noise ratio of portal vein and lesions as well as pancreatic tissues and lesions (CNR PV, CNRtumor) were also compared. At the same time, two imaging physicians with rich clinical experiences read the films and scored the images of each group by using the 5-point scoring method. Results: Mono+ 55 keV images including SNRpv, SNRpanc, SNRtumor, Noise, CNRpv, CNRtumor were statistically different from 100 KV images and Mono_E images (P < 0.05). As for the subjective score, Mono+ 55 keV image score also had the highest score, which had statistical significance (P < 0.05). The results showed that Mono+ 55 keV images had the best quality. Conclusion: The new generation of virtual Mono+ post-treatment can reduce image noise. Low energy Mono+ images can improve the contrast between pancreatic cancer lesions and portal of pancreatic cancer patients.

Advancement in Wide Area Monitoring Protection and Control Using PMU’s Model in MATLAB/SIMULINK

A big step forward to improve power system monitoring and performance, continued load growth without a corresponding increase in transmission resources has resulted in reduced operational margins for many power systems worldwide and has led to operation of power systems closer to their stability limits and to power exchange in new patterns. These issues, as well as the on-going worldwide trend towards deregulation of the entire industry on the one hand and the increased need for accurate and better network monitoring on the other hand, force power utilities exposed to this pressure to demand new solutions for wide area monitoring, protection and control. Wide-area monitoring, protection, and control require communicating the specific-node information to a remote station but all information should be time synchronized so that to neutralize the time difference between information. It gives a complete simultaneous snap shot of the power system. The conventional system is not able to satisfy the time-synchronized requirement of power system. Phasor Measurement Unit (PMU) is enabler of time-synchronized measurement, it communicate the synchronized local information to remote station.

Comparison of low-dose sequences of dual-source CT and echocardiography for preoperative evaluation of aortic valve disease

Background Accurate evaluation of coronary artery,aortic valve annulus diameter （AVAD）,and cardiac function in patients with aortic valve disease is of great significance for surgical strategy.In this study,we explored the preoperative evaluation of low-dose sequence （MinDose sequence） scan of dual-source CT （DSCT） for those patients.Methods Forty patients suspected for aortic valve disease （the experimental group） underwent MinDose sequence of DSCT to observe coronary artery,AVAD,and left ventricular ejection fraction （LVEF）.Another 33 subjects suspected for coronary artery disease （the control group） underwent conventional retrospective electrocardiographically-gated sequence of DSCT.Two-dimensional transthoracic echocardiography （2D-TTE） and four-dimensional transthoracic echocardiography （4D-TTE） were applied in the experimental group to measure AVAD and LVEF and compared with MinDose-DSCT.Results There was a strong correlation between LVEFs measured by 2D-TTE and MinDose-DSCT （r=0.87,P ＜0.01）,as well as between 4D-TTE and MinDose-DSCT （r=0.90,P ＜0.01）.AVAD measured by MinDose-DSCT was in good agreement with corresponding measurements by 2D-TTE （r=0.90,P ＜0.01）.The effective dose in the experimental group was 63.54％ lower than that in the control group.Conclusions MinDose sequence of DSCT with a low radiation dose serving as a one-stop preoperative evaluation makes effective assessment of the coronary artery,AVAD,and LVEF for patients with aortic valve disease.

Relationship of Cystatin-C with coronary artery disease in the elderly patients with diabetes

Objective: To study the relationship between Cystatin C (Cys-C) level and the development of coronary heart disease in elderly patients with type 2 diabetes mellitus (T2DM). Methods: 120 cases of elderly diabetic patients were involved in this study from October 2013 to November 2015 in Depart-ment of Endocrinology and Cardiology. All patients underwent the detection of routine flash dual-source coronary computed tomography angioplasty (CCTA), Cys-C, hemoglobin A1c (HbA1c). According to the difference of CCTA results, the patients were divided into DM1 group (with normal coronary CTA), DM2 group (with a coronary artery stenosis rate < 50%), DM3 group (with a coronary artery stenosis rate of 50%-74%) and DM4 group (with a coronary artery stenosis rate of ≥ 75%). The levels of Cys-C and HbA1c were compared in the four groups. Results: The blood levels of Cys-C and HbA1c showed significant differences between DM1, DM2, DM3 and DM4 group (p <.05). The age, heart rate, blood pressure showed no statistical differences between the groups. The level of Cys-C was positively correlated with HbA1c. Conclusions: The blood level of Cys-C in the elderly patients with T2DM increased with the increase of the degree of coronary artery stenosis. Blood Cys-C may be used as an early predictor of coronary artery lesions in elderly patients with T2DM.

心脏电机械偶联与Flash双源CT冠状动脉成像在高心率患者中的应用(英文)

Objective To assess the image quality and effective radiation dose of prospectively electrocardiogram-triggered high-pitch spiral acquisition (flash spiral mode)dual-source CT coronary angiography in patients with high heart rate(HR).Methods From 1321 consecutive patients,seventy patients with HR≥70 bpm (group A) and seventy patients with HR<70 bpm (group B) underwent CT angiography and were prospectively included in this study.The start phase for image acquisition of the most cranial slice was selected at 20%-30% of the R-R interval for group A and at 60% of the RR interval for group B.Assessed the image quality and effective radiation dose of two group.Results (1)There were no significant differences in age,sex,BMI and scan time between the two groups.(2)Image qualities:The segments with non-diagnostic image quality occurred (i.e.score 3) had no significant difference between group A and group B (2.1% vs.1.5%,P=0.48).Non-diagnostic image quality was most often found in the RCA and LCX in both groups.(3)The estimated radiation dose was on average (1.00±0.15) mSv(0.7-1.82 mSv) in group A and (1.01±0.16)mSv (0.65-1.82 mSv) in group B.Conclusions Patients with high heart rates can be performed CTCA with high-pitch spiral acquisition mode.20%-30% of the R-R interval window for data acquisition for high-pitch dual-source CTCA may probably obtain good image quality with low doses.The highest HRs are 100 bpm with good image quality.HR variability is a great effect factor of image quality.The estimated radiation dose is about 1 mSv.

心房颤动患者的低剂量、大螺距双源CT冠状动脉成像的可行性研究(英文)

Objective The objective was to attempt to rule out whether high-pitch spiral acquisition dual-source computed tomography coronary angiography(CTCA)can be performed in patients with atrial fibrillation at low dose.Methods Ten patients with atrial fibrillation who were admitted for a first diagnostic coronary angiogram were screened for participation.All patients underwent dual-source CT.Patients were performed CTCA using the prospectively ECG-gated high-pitch mode and retrospective ECG gating spiral acquisition respectively with their permissions.The start phase for image acquisition of the most cranial slice was selected at 20%-30% of the R-R interval in all patients.Results Image qualities of prospectively ECG-gated high-pitch mode were rated as being excellent in 7 cases of all the patients and only 3 cases′ image qualities were graded score 2.By using retrospective ECG gating spiral acquisition mode,non-diagnostic image quality (score 3) occurred in 4 patients which were observed in RCA and 1 patient in LCX.The estimated radiation dose ranges from 0.68 to 1.887 mSv in flash mode and the radiation dose of spiral mode were very high ranging from 14.92 to 29.308 mSv.Conclusions Our case series suggest that patients with atrial fibrillation rhythm can be performed CTCA with high-pitch spiral acquisition mode.20%-30% of the RR interval window for data acquisition for high-pitch dual-source CTCA may probably obtain good image quality with low doses.