基于GPUs可视化技术的心脏辅助诊断系统研究

目的:实现基于GPUs的心脏断层图像的精确分割和三维可视化,完成心脏辅助诊断系统的设计。方法:结合临床专家诊断经验、心脏CT图像先验特征和图像分割算法模型,采用GPUs并行数据处理技术实现心脏结构的分割和三维可视化。结果:完成了CT心脏序列图像的精确、快速、鲁棒分割和三维可视化,初步实现了基于GPUs的可视化技术的心脏辅助诊断系统。结论:研究充分利用计算机图形处理单元GPU强大的并行计算能力,解决了医学图像处理和分割中的问题,提高了程序的运行效率,改善了用户体验。     

Comparison study of echocardiography and dual-source CT in diagnosis of coronary artery aneurysm due to Kawasaki disease: coronary artery disease

The identification of coronary artery aneurysm (CAA) in the acute and chronic phase of the disease is of prime importance for assessing the likelihood of acute lesions and cardiovascular sequelae. Occasionally, recognition of distal coronary artery has been proven challenging by traditional echocardiography. Our purpose was to evaluate the clinical application of two-dimensional echocardiography (2DE) for detecting CAA caused by Kawasaki disease (KD) and compare with dual-source computed tomography (DSCT). A total of 24 patients with known KD and CAAs were studied by two imaging modalities, i.e., 2DE and DSCT; that is to say, the number, position, shape, and size of each CAA and its association with thrombus, were detected first from echocardiography and then compared with those obtained from DSCT performed on the same day. Meanwhile the diameters of all coronary segments were measured for each patient. Giant aneurysms (GAs) were detected in 5 patients, small and medium coronary aneurysms were identified in 19 patients. The 2DE and DSCT have the same results of proximal coronary artery, whereas conclusion of our comparison of coronary artery visualization indicated that DSCT provided more explicit distal coronary artery than 2DE. A mural thrombus could be clearly delineated in the GAs by DSCT. The 2DE has been demonstrated to be an accurate technique to quantify CAAs in KD. However, DSCT is superior to 2DE for distal coronary artery visualization. Therefore, a combination of echocardiography and DSCT can offer an overview of coronary artery anatomy.     

Integration of dual source computed tomography With magnetic navigation system for percutaneous coronary intervention: A feasibility study

Objectives : To investigate the feasibility of integration of the dual source computed tomography (DSCT) and magnetic navigation system (MNS) to guide percutaneous coronary intervention (PCI). Background : MNS has proven to be feasible for yielding high rates of procedural success for PCI. DSCT coronary angiography (DSCT‐CA) may provide a roadmap of a target vessel and serve as a reference route for MNS. Combination of these two technologies might decrease the contrast use, fluoroscopy exposure, and be beneficial to the intervention of the totally occluded lesions. Methods : Twenty‐five patients with positive results of DSCT‐CA and indications for PCI were included. CT images were transferred to MNS, and target vessels were extracted and registered to X‐ray system as a roadmap. Results : DSCT‐CA and MNS‐assisted PCIs were successfully performed in 25 of the 26 target vessels (96.2%), with the mean guidewire crossing time of 100.0 (25–75% inter‐quartile ranges (IQR): 70.7–157.8) sec, mean total radiation dosage of 268.1 (IQR: 150.5–527.0) μGym², or 42.0 (IQR: 23.0–70.0) mGy, respectively. The contrast usage for guidewire positioning was 0 (IQR: 0–3.0) ml for the successfully crossed lesions. Both of the two totally occluded lesions in this study were successfully crossed with guidewires under the guidance of the DSCT‐CA derived roadmap. Conclusion : Integration of DSCT with MNS for PCI is feasible. This integration of advanced modalities might decrease contrast usage, lower fluoroscopy exposure for guidewire positioning, and might also play a role in totally occluded lesions. © 2011 Wiley Periodicals, Inc.     

双源CT在检测冠状静脉系解剖变异特点中的应用

目的利用双源CT(DSCT)检测冠状静脉系(CVS)的解剖学变异类型。方法对疑有冠状动脉疾病的199例患者行DSCT检查。扫描后对其CVS进行三维重建和2D的多重切面改组重建。结果所有病例均可清晰显示冠状窦。共鉴定出27种CVS的解剖学变异类型,其中9种最常见(148例/199例;74.4%)。除此之外有4种类型在行心脏再同步治疗(CRT)时显示的靶区域中仅有1条冠状静脉出现,3种变异类型靶区域中有2条靶静脉出现,2种变异类型靶区域中有3条靶静脉出现。6例病例(2种很少见的变异类型,占3.0%)在靶区域中没有静脉出现。结论被检查的患者中大多数在CRT靶区域中至少能观察到1条静脉。CVS的解剖学变异性增强了DSCT在CRT植入前对CVS可视化中的应用价值。     

Myocardial Ischemia Evaluation With Dual-source Computed Tomography: Comparison With Magnetic Resonance Imaging

Introduction and objectives

Computed tomography does not accurately determine which coronary lesions lead to myocardial ischemia and consequently further tests are required to evaluate ischemia induction. The aim of this study was to compare diagnostic accuracy between dual-energy computed tomography and magnetic resonance imaging in the assessment of myocardial perfusion and viability in patients suspected of coronary artery disease.

Methods

A prospective study was performed in 56 consecutive patients (39 men [69.6%]; mean age [standard deviation], 63 [10]; range, 23-81). Computed tomography was performed with the following protocol: 1, adenosine stress perfusion; 2, coronary angiography; and 3, delayed enhancement. Magnetic resonance imaging for the evaluation of stress perfusion and delayed enhancement was performed within 30 days. Two observers in consensus analyzed the perfusion and delayed enhancement images.

Results

We studied 952 myocardial segments and 168 vascular territories. In a per-segment analysis, the sensitivity, specificity, and positive and negative predictive values of computed tomography compared with magnetic resonance were 76%, 99%, 89%, and 98% for perfusion defects, and 64%, 99%, 82%, and 99% for delayed enhancement, respectively. In a per-vascular territory analysis, the same measures were 78%, 97%, 86%, and 95% for perfusion defects, and 72%, 99%, 93%, and 97% for delayed enhancement, respectively. The mean radiation dose was 8.2 (2) mSv.

Conclusions

Dual-source computed tomography may allow accurate and concomitant evaluation of perfusion defects and myocardial viability and analysis of coronary anatomy.     

64层双源螺旋CT原理

介绍了64层双源螺旋CT概念，分析了其组成和特点，说明了其对冠状狭窄性病变性质鉴别的独特优势。并对双源螺旋CT成像原理及其双能量减影成像原理进行了详尽阐述，展示了其广阔的应用前景。     

Cortically evoked pre-and postsynaptic inhibition of impulse transmission to the dorsal spinocerebellar tract

Summary Synaptic actions evoked from primary afferents and the sensorimotor cortex in neurones of the dorsal spinocerebellar tract were investigated: 1. Stimulation of the anterior lobe of the cerebellum produced a small IPSP in only one but not in the other six neurones examined. 2. IPSPs were induced not only from group I fibres (in 41% of group I neurones) but also from cutaneous and/or high threshold muscle afferents (in 37%). 3. Stimulation of the contralateral sensorimotor cortex evoked IPSPs in 80% of group I neurones. The IPSP had a latency of 10–15 msec and lasted for 40–100 msec. EPSPs were evoked from the cortex in a small number of neurones. 4. Effects from the cortex were compared with those from primary afferents in individual neurones. The cortical IPSPs were induced independently of whether the neurone received monosynaptic EPSP from extensor or flexor group I fibres. The cortical IPSPs (or EPSPs) occurred more frequently in neurones which exhibited polysynaptic IPSPs (or EPSPs) from primary afferents. 5. The few FRA neurones encountered were all excited from the cortex.Excitability measurements of primary afferent terminals in or near Clarke's column showed that a terminal depolarization is evoked from the cortex in group Ib but not in Ia afferents.The relative importance of post-and presynaptic inhibition of transmission to the DSCT is discussed.     

Global left-ventricular function assessment using dual-source multidetector CT: effect of improved temporal resolution on ventricular volume measurement

The purpose was to compare global left-ventricular (LV) function parameters measured with cine MRI with results from multiphase dual-source CT (DSCT) using 10 and 20 reconstruction phases. Twenty-eight patients with suspected or known CAD underwent DSCT coronary angiography. LV end-diastolic (EDV), end-systolic (ESV) and stroke volumes (SV), and ejection fraction (EF) were determined using LV segmentation and selection of specific phases from DSCT image sets reconstructed either at 5% or 10% steps through the R-R interval. Cine MRI served as the reference investigation. Threshold-based 3D-segmentation was feasible in all DSCT data sets. EDV and ESV were underestimated by DSCT, but showed excellent correlation (Pearson's correlation coefficient 0.95/0.97) to values obtained with MRI. Using data from 5% DSCT image reconstructions instead of 10% phase reconstructions, the position of the ED and ES phase was changed in 16 of 28 patients; ESVs were to found to be slightly smaller, whereas EDV were slightly larger, resulting in a systematic overestimation of LV EF by 1.9% (p = 0.56). Threshold-based 3D segmentation enables accurate and reliable DSCT determination of global LV function with excellent correlation to cine MRI. Minor differences in LV EF indicate that both modalities are virtually interchangeable, even if the number of reconstructed phases is limited to 10% phase reconstructions.     

双源CT与超声心动图定量评价冠心病左心功能的比较研究

目的:以超声心动图为对照标准,探讨双源CT定量评价左心功能的可行性和准确性及其优势。方法:选取2011年1月～6月冠心病患者58例,其中合并II型糖尿病患者29例。全部病例于3天内行心脏双源CT及超声心动图检查。比较双源CT与超声心动图所测得的左心功能各参数。结果:双源CT和超声心动图所测左心功能各指标EDV、ESV、SV、EF相关性高(r=0.702～0.898),差异无统计学意义(P>0.05)。两种方法所测冠心病合并II型糖尿病组左心功能指标EDV、ESV值均较非糖尿病组测值高,EF值较低,差异均有统计学意义(P<0.05)。结论:两种方法评价左心功能相关性好,双源CT是一种评价左心功能准确可行的方法,一次冠状动脉造影所获得的数据,不但可评价左心功能,还可评价冠脉狭窄情况,无需额外增加对比剂和辐射剂量。