Objective:To study the feasible training model of graduate students with professional degree. Methods:According to the purpose of training-clinical skills of graduate students with professional degree in department of radiology, we have made several ways to ensure the procedural and standardization of the training from course setting, multiple level clinical operation training, the ability of study and evaluation system. Results:To introduce the mode by using evaluation system and to standardize the steps. Conclusion:The model which includes proper course setting, multiple level clinical operation training, the ability of study and evaluation system can enhance the clinical skill training and advance the professionalism of the students.

Abdominal aortic aneurysm (AAA) is a common aortic disease causing death. Many factors are associated with AAA rupture, such as aneurysm diameter, shape, intraluminal thrombus, and hemodynamic changes. It has been shown that hemodynamic changes may be one of the main risk factors for AAA rupture. There are several imaging modalities to evaluate AAA, in which Doppler ultrasound and magnetic resonance blood flow imaging are capable of assessing the hemodynamic changes in AAA. This review will discuss the risk factors for rupture and imaging advancement of AAA.

Abdominal aortic aneurysm (AAA) is a common fatal aortic disease.The rupture of AAA is the procession affected by multiple factors.Besides physiological,pathological and biochemical changes,morphological and biomechanical alteration can also influence this procession.The progress of rupture risk evaluation through morphological and biomechanical characteristics of AAA were reviewed in this article.

Objective:To investigate the training of writing research paper for graduate students majoring in medical imaging, therefore improving international academic communication. Methods: Analyzing the problems existed in English paper writing for the graduate students majoring in medical imaging. According to the feature of English paper writing in the field of medical imaging, the new teaching model was used and the problem-based-learning method was introduced.Results: The new training model of English research paper writing is practical and helpful for graduate students majoring in medical imaging to improve their writing skill and research ability.Conclusion: The training of English research paper writing is efficient for graduate students majoring in medical imaging. The training process can lay good foundation for their future research careers.

Objective To analyse the flow characteristics in the true lumen and false lumen,and the relationship between the flow characteristics and the collapse degree of the true lumen using MRI.Methods Eleven patients with acute Stanford type B aortic dissection were examined by true FISP、3D CE MRA、PC cine MRI on a Siemens Sonata 1.5 T.Not only the quantitative data on the hemodynamics such as peak velocity,average velocity,average flow volume,forward volume,retrograde volume and net volume,and the area of the true lumen and false lumen can be acquired,but also the blood flow model,ie the velocity-mapping.Then we analysed the relationship between the flow characteristics and the collapse degree of the true lumen.Results The average area of the false lumen in the proximal descending aorta(about 2 cm distal to the entry)was(8.10±2.93)cm2,and(2.59±0.93)cm2 of the true lumen in the same slice (P＜0.05).The average velocity in the false lumen,(2.81±0.73)cm/s,was significantly lower than in the true lumen[(15.52±2.84)cm/s,P＜0.01],wheras the average flow(36.32±5.37)ml/s,was not significantly difierent(P＞0.05)from the average flow in the false lumen(37.62±24.58)ml/s.The velocity-mapping curve looked like same in the true and false lumen in this level.And in the abdominal aorta(about the level of the hepatic hilar),the average flow(10.46±5.57)cm/s was significantly lower(P＜0.05)than in true lumen[(4.04±2.96)cm/s].At this level,the direction of blood flow in the true lumen was retrograde(upward)in the mid and late systolic phase in six patients,and normal in the diastolic phase and early systolic phase,that was to say,bidirectional blood flow can be caught in the true lumen of the abdominal aorta.The collapse degree of the true lumen was closely correlated with the the average velocity and the flow volume in the false Iumen,and the coefficient correlation and P value were 0.931 and 0.000,0.926 and 0.000 respectively.Conclusions PC cine MRI can quantitatively measure the peak velocity,average velocity,average flow volume,forward volume,retrograde volume and net volume,and combined with 3D CE MRA can evaluate the collapse degree of the true lumen.It is important for clinical application in the diagnosis,therapeutic management and the therapeutic opportunity choice of the acute Stanford type B aortic dissection.

Objective To evaluate the methods and the factors of affecting imaging quality of 3D CE MRA of carotid arteries.Methods 3D CE MRA in 48 patients were performed using 1.5T super conductive MR scanner,cervical and lumbar combination phased array coils. All patients were examined using intravenous injection Gd-DTPA and breath-hold 3D FLASH sequence. Results Imaging quality was satisfied in 46/48 patients (96%). MIP and MPR could clearly showed normal anatomy. The site,size and stenosis degree of the lesion were also demonstrated. Compared to surgery,DSA and/or ultrasound results , in 23 patients, the sensitivity and specificity of 3D CE MRA were 100% and 100% respeectively for the lesion of carotid arteries. Conclusion High quality images of 3D CE MRA mainly depends on determining the best acquisition delay time,optimizing injection volume and rate of contrast material,using reasonable sequence parameters and skilled level of operators.

Objective To prospectively evaluate the feasibility and reliablity of low kilovoltage contrast-enhanced multi-slice CT(MSCT)to detect the myocardial viability in chronic myocardial infarcetion.with comparison to magnetic resonance(MR)myocardial perfusion and viability imaging.Methods Thirty-two patients with clinical diagnosed chronic myocardial infarction underwent the first pass and delayenhanced myocardial imaging with 64-slice MSCT and MR Left ventricle was divided into 16 segments.MSCT and MR images of all the patients were blindly analyzed.The size and extent of hypoenhanced regions in first pass phase and hyperenhanced regions in delayed phase were define.The Kappa test was used to assess the ability of identifying the viable myocardium between the two methods.Results In 32 patients with chronic myocardial infarction,MSCT showed hypoenhanced regions in 41 segments and normal in 471 segments during the first phase,while MRI revealed hypoenhanced regions in 47 segments and normal regions in 465 segments.The Kappa value was 0.650 and the concordance rate of the two techniques was 94.5%(484/512).MSCT showed 135 hyperenhanced regions which were non-transmural in 50 segments and transmural in 85 segments.And the other 377 normal segments showed no enhancement in the delayed phase.MRI revealed 120 hyperenhanced regions which were non-transmural in 56 segments and transmural in 64 segments.And the other 392 normal segments showed no enhancement in the delayed phase.The Kappa value of the two techniques was 0.609 and the concordance rate of the two techniques was 80.7% (413/512).Conclusion The study showed that low kilovolrage CE MSCT has a good concordance with MRI and has high feasibility and reliability in evaluating the myocardial viability in chronic myocardial infarction.The radiation dose is still the important aspect of MSCT application.

Objective To evaluate low-dose CT coronary angiography with prospective electrocardiogram (ECG)-triggering using dual-source CT scanner.Methods Sixty-eight patients who underwent coronary CT angiography using a dual-source CT scanner were divided into 2 groups: group A (38 cases) and group B (30 cases).Prospective ECG-triggering sequence scan mode was employed for group A.Inclusion criteria included: heart rate <70 bpm, sinus rhythm, and heart rate fluctuation less than 10 bpm.Data acquisition was set at 70% of the RR-interval.Retrospective ECG-gating helical scan was performed for group B.Inclusion criteria included heart rates < 70 bpm and sinus rhythm.The exclusion criteria included heart failure and serious arrhythmias.In both groups, patients with a BMI≥24 kg/m2 were examined with a tube voltage of 120 kV, whereas patients with a BMI <24 kg/m2 were examined with a tube voltage of 100 kV.All images were transferred to a workstation for further processing and analysis.The imaging quality was evaluated.The imaging quality of coronary artery segments were compared with rank sum test between the two groups, and the radiation dose were compared with t test.Results A total of 476 coronary artery segments were evaluated in group A and 372 segments were evaluated in group B.The mean score of imaging quality for coronary artery segments in group A was 3.48±0.59 and that in group B was 3.53±0.58.There was no statistical difference in imaging quality between the two groups (Z=-1.432, P=0.187).The effective dose was on average (2.51±0.54) mSv (range 1.3--3.3 mSv) in group A, whereas on average (14.55±3.54) rosy (range 7.1--20.2 mSv) in group B.There was a statistical difference between the two groups (t=18.484, P=0.000).Conclusions Low-dose prospective ECG-triggering sequence scan in dual-source CT coronary angiography is feasible in patients with low heart rate and regular cardiac rhythm.This scan mode can substantially reduce radiation doses while preserving good diagnostic image quality.

Objective The optimal treatment for chronic type B dissection remains controversial. The purpose of this study was to report early and mid-term results of thoracic endovascular aortic repair (TEVAR) of chronic type B aortic dissection. Methods Methods From June 2001 to September 2007, 84 patients with chronic type B aortic dissection received TEVAR. The time between onset of dissection and TEVAR was (13.9 ± 22.0) months (ranged 1 - 120 months). All patients were followed for 6 - 86 months [mean (33.2 ± 19.2) months]. Results The entry tear was completely sealed in 77 cases ( 91.7% ) during TEVAR. The incidence of incomplete seal was 8.3%. One-month mortality was 1. 2%. One patient had retrograde type A dissection 1 month after operation. Four patients received a second TEVAR during follow-up :3 for endoleaking and 1 for newly formed intima tear. Seven patients (8.3%) died during follow-up: 3 thoracic aorta rupture due to endoleaking, 1 abdominal aorta rupture caused by continuous dilation of the abdominal aorta, unrelated to aortic dissection deaths in 2 and 1 died of unknown cause. The Kaplan Meier actuarial survival curve showed a 7-year survival rate of 84.4%. Conclusion Early and mid-term results showed that TEVAR was effective in treating chronic type B aortic dissection. Endoleak was the main cause of death during follow-up. With increasing of physician's experience and refinement of the stent-graft, results are likely to improve in the future.

Objective To study the value of dual-source CT(DSCT)in assessing aortic mechanical valve with 3D cardiovascular imaging technique.Methods Thirty-four patients with mechanical aortic valve transplantation were enrolled.Nineteen cases transplanted with On-x valve and 15 cases with St jude valre.CT scan was performed in all 34 patients and MRI scan in 30 patients.The CT imaging quality of On-x valve with St jude valve was compared by two independent samples Wilcoxon rank test.Two independent sampies test was used to compare tlle valve angle in the two kinds of valve and also in the same group.The relative functional index of left ventricle in CT and MR analysis by paired-samples t Test. Results The image quality was dirided into three grades.Six hundred and eighty phases in all 34 patients.which included 391 phases with grade 1,171 phases with grade 2 and 118 phases with grade 3.There were no significant different between two kinds of mechanical valve in image quality(image quality of grade 1:Z=-1.084,P=0.286;grade 2:Z=-0.088,P=0.945;grad 3:Z=-1.045,P=0.319).The mean bileaflet angle of 34 cases was 82.0°±4.4°in completely opening and 34.5°±5.7°in completely closing.The mean radian gradient over openess and closure was 47.5°±7.5°.The radian gradient of St iude group(55.0°±1.8°)was obviously larger than On-x group(41.5°±4.1°)(t=-11.732,P=0.000).But,there were no significant difference between dual-source CT and 1.5 T MR when evaluate the left ventrical fuction,including EF[MR.EF(57.2-1-2.8)%,CT-EF(57.9±2.8)%,f:-0.496,P=0.623],EDV[MR-EDV (121.6±9.1)ml,CT-EDV(132.9±11.2)ml,t=-1.198,P:0.240],ESV[MR-ESV(55.1±6.9)ml,CT-ESV(59.5±7.6)ml,t=-1.094,P=0.283],myocardium mass at ED[MR-Myo.mass (155.5 ±12.6)g,CT-Myo.mass(147.9±11.6)g,t=1.823,P=0.079]and CO[MR-CO(5.7±0.4)ml/min,CT-CO(5.9±0.5)ml/min,t=-3.211,P=0.775].Conclusions Dual source CT with 3D cardiovascular imaging technique is valuable and effective for evaluating aortic mechanical valve.The shape of the whole valve and movement of bileaflet reappears well.With the postprocessing software,it allows evaluating aortic mechanical valve function,reliable measurements of opening and closing leaflet angles and left ventrieal function.