犬囊状动脉瘤模型的制作

本文报道用“静脉囊镶嵌技术·制成犬的囊状动脉瘤模型。18个模型(6个单侧型,6个分叉型,6个末梢型)造型后2周经IA DSA检查。本模型在分型、血流动力学改变方面与人类囊状脑动脉瘤类似。不同类型的动脉瘤模型既有相同的血流动力学特征,又有各自的特点,这与动脉瘤与载瘤动脉的角度有关。我们认为该模型可应用于研究动脉瘤的血流动力学与血管内栓塞治疗。     

Willis环状脑动脉瘤生物数学模型的周期与概周期解

本文运用构造Liapunov函数的方法,在一定条件下,证明了Willis环状脑动脉瘤生物数学模型存在唯一的周期与概周期解．     

腹主动脉瘤的流固耦合分析方法研究

目的:将流固耦合分析方法运用于血流动力学的研究,可以获得更加准确的结果,为临床诊断和治疗提供有效的指导.方法:本文运用ANSYS和CFX对腹主动脉瘤(Abdominal Aortic Aneurysm,AAA)进行流固耦合模拟分析,以便获得动脉瘤的血流速度和瘤壁的应力分布,判断易破裂危险区域.结果:实验结果表明,本例的腹部主动脉瘤应力峰值位于瘤体颈部.结论:流动和壁面切应力分布揭示动脉瘤颈部为破裂的危险区域.     

显微外科手术治疗破裂前循环脑动脉瘤的临床研究

目的:旨在进一步提高手术治疗破裂的前循环脑动脉瘤的效果.方法:回顾性分析显微手术治疗的56例破裂前循环脑动脉瘤患者的临床资料.结果:56例病人,共61个脑动脉瘤,其中45枚行动脉瘤颈夹闭,6枚夹闭瘤颈后切除瘤体,另10枚动脉瘤予以瘤壁包裹加固术.术后第3天发生血管闭塞1例,遗留肢体偏瘫.25例随访1个月～5年,恢复良好17例,中残或重残2例,死亡2例.结论:显微手术治疗破裂的脑动脉瘤,不仅有效地防止再出血,而且有利于脑血管痉挛的防治.术后扩充血容量,提升血压,扩张血管对防治脑血管痉挛具有相当好的疗效.     

一类周期种群系统的稳定性分析及最优控制问题

本文讨论了一类线性时变周期种群系统的稳定性和最优控制问题.利用Lyapunov函数.对系统的稳定性进行了分析.给出了系统稳定的充分条件.并且利用Banach空间理论,证明了最优收获控制的存在性和唯一性.并且给出了最优控制所满足的必要性条件.     

KF-3000脑循环分析仪

KF-3000脑循环分析仪是上海匡复医疗设备发展有限公司和复旦大学联合研究基础上开发的新一代的脑循环动力学检测与分析仪器。它通过无创检测颈动脉的血流速度、血液压力、血管管径和人体血压,以及颅内大脑两侧前、中、后动脉及椎动脉的血流速度,运用脑循环动力学模型和专用计算软件来计算分析反映脑循环功能状况的脑血管动力学参数。     

KF-3000脑循环分析仪

KF-3000脑循环分析仪是上海匡复医疗设备发展有限公司和复旦大学联合研究基础上开发的新一代的脑循环动力学检测与分析仪器。它通过无创检测颈动脉的血流速度、血液压力、血管管径和人体血压,以及颅内大脑两侧前、中、后动脉及椎动脉的血流速度,运用脑循环动力学模型和专用计算软件来计算分析反映脑循环功能状况的脑血管动力学参数。     

KF-3000脑循环分析仪

KF-3000脑循环分析仪是上海匡复医疗设备发展有限公司和复旦大学联合研究基础上开发的新一代的脑循环动力学检测与分析仪器。它通过无创检测颈动脉的血流速度、血液压力、血管管径和人体血压,以及颅内大脑两侧前、中、后动脉及椎动脉的血流速度,运用脑循环动力学模型和专用计算软件来计算分析反映脑循环功能状况的脑血管动力学参数。     

KF-3000脑循环分析仪

KF-3000脑循环分析仪是上海匡复医疗设备发展有限公司和复旦大学联合研究基础上开发的新一代的脑循环动力学检测与分析仪器。它通过无创检测颈动脉的血流速度、血液压力、血管管径和人体血压,以及颅内大脑两侧前、中、后动脉及椎动脉的血流速度．运用脑循环动力学模型和专用计算软件来计算分析反映脑循环功能状况的脑血管动力学参数。     

基于Laplace变换的Wills环状脑动脉瘤生物数学模型的周期解

本文主要运用Laplace变换的方法,对Wills环状脑动脉瘤的生物数学模型在满足初始条件下进行研究,得到了该模型解的具体表达形式,以及存在固定周期解的结论.     

Migraine with Aura Is Associated with an Incomplete Circle of Willis: Results of a Prospective Observational Study

Objective

To compare the prevalence of an incomplete circle of Willis in patients with migraine with aura, migraine without aura, and control subjects, and correlate circle of Willis variations with alterations in cerebral perfusion.

Methods

Migraine with aura, migraine without aura, and control subjects were prospectively enrolled in a 1∶1∶1 ratio. Magnetic resonance angiography was performed to examine circle of Willis anatomy and arterial spin labeled perfusion magnetic resonance imaging to measure cerebral blood flow. A standardized template rating system was used to categorize circle of Willis variants. The primary pre-specified outcome measure was the frequency of an incomplete circle of Willis. The association between circle of Willis variations and cerebral blood flow was also analyzed.

Results

170 subjects were enrolled (56 migraine with aura, 61 migraine without aura, 53 controls). An incomplete circle of Willis was significantly more common in the migraine with aura compared to control group (73% vs. 51%, p = 0.02), with a similar trend for the migraine without aura group (67% vs. 51%, p = 0.08). Using a quantitative score of the burden of circle of Willis variants, migraine with aura subjects had a higher burden of variants than controls (p = 0.02). Compared to those with a complete circle, subjects with an incomplete circle had greater asymmetry in hemispheric cerebral blood flow (p = 0.05). Specific posterior cerebral artery variants were associated with greater asymmetries of blood flow in the posterior cerebral artery territory.

Conclusions

An incomplete circle of Willis is more common in migraine with aura subjects than controls, and is associated with alterations in cerebral blood flow.     

宏观生物经济系统线性二次型问题的稳定性分析

本文用控制方法研究宏观生物经济系统,对其进行了线性二次型最优控制设计,给出了该系统的线性二次型问题模型,并对其稳定性进行分析,利用李雅普诺夫稳定性定理,证明了该控制设计的最优控制系统是大范围稳定的,从而得到了该系统在线性二次型控制下保持生物产业经济稳定增长的结论,最后通过仿真验证了结论的正确性．     

Toward large-scale computational fluid-solid-growth models of intracranial aneurysms

Complementary advances in medical imaging, vascular biology, genetics, biomechanics, and computational methods promise to enable the development of mathematical models of the enlargement and possible rupture of intracranial aneurysms that can help inform clinical decisions. Nevertheless, this ultimate goal is extremely challenging given the many diverse and complex factors that control the natural history of these lesions. As it should be expected, therefore, predictive models continue to develop in stages, with new advances incorporated as data and computational methods permit. In this paper, we submit that large-scale, patient-specific, fluid-solid interaction models of the entire circle of Willis and included intracranial aneurysm are both computationally tractable and necessary as a critical step toward fluid-solid-growth (FSG) models that can address the evolution of a lesion while incorporating information on the genetically and mechanobiologically determined microstructure of the wall.     

The variability of the circle of Willis: univariate and bivariate analysis

The results are presented of a statistical analysis of the variability of the circle of Willis using univariate and bivariate methods. For this purpose 100 circles of Willis were available. From each circle 19 indexes of arterial size were determined, the basilar artery was measured in two places. Half the circumference was measured. This data yielded no evidence of differences between left- and right-sided vessels in the sample. An important source of variation is the general size of all vessels considered. When the data are cleared from this general size variation, correlation coefficients reveal interesting relations between the vessels. The posterior communicating arteries are strongly related to the ipsilateral carotid artery, whereas a strong inverse relationship exists with the basilar artery and the precommunicating part of the ipsilateral posterior cerebral artery. These relationships can be understood from the expected patterns of the blood flow in these vessels. Similar relationships can be found in the anterior part of the circle of Willis and in the vertebro-basilar junction. In a different manner, based on previous haemodynamic studies, the relation between blood flow and vessel size within the circle of Willis can be demonstrated by relating the ratios of the sizes of afferent and efferent arteries to the sizes of the posterior communicating arteries, an "intuitive" model. The supposed correlations of the outcome of this "intuitive" model with the size of the communicating arteries appeared to by highly significant. It is concluded that the variations of the circle of Willis are related to the individual variations of the blood flow in this arterial network.     

Mechanics of rupture of cerebral saccular aneurysms

Most saccular aneurysms initiate in human intracranial arteries in and about the circle of Willis. Rupture of an aneurysm causes subarachnoid hemorrhage which seriously endangers the patient's life.

To study the possible cause of rupture, a dynamic analysis is performed. A thin-shell theory is applied to a spherical model subjected to time-dependent internal pressure and boundary conditions. The fundamental differential equations are found by combining the equations of motion, strain-displacement relations, and stress-strain relations.

The solution involves Legendre functions of the first kind. Natural frequencies of aneurysms of different sizes and closing angles are determined as functions of the elastic properties. These properties are investigated by using data from the literature.

It is found that the natural frequencies of certain types of aneurysms fall within the range of bruit frequencies that commonly accompany aneurysms. Resonance and consequently rupture is then expected when the bruit frequency is the same as the natural frequency of the aneurysm. Critical aneurysm sizes, for various closing angles, are predicted.     

Mathematical model of aneurysm of the circle of Willis: II. a qualitative analysis of the equation of Austin

Periodic solutions of the equation derived by Austin [1,1e] to describe an aneurysm of the circle of Willis are studied by qualitative methods which are extensions of the method of Poincaré. The results obtained reinforce strongly Austin's conclusion concerning the danger of increased pulse pressure; they suggest the possibility of the danger of an increased pulse rate (this also agrees with Austin's conclusions) or a decreased pulse rate. The conclusions provide a theoretical justification for the treatment of intracranial aneurysms by hypotensive methods [14] and also an explanation of why there does not seem to be an immediate precipitating cause of rupture (i.e., rupture seems to be just as likely to occur during relaxation as during physical activity).     

Effect of elevated catecholamine levels on cerebral hemodynamics in patients with chronic post-traumatic stress disorder

The aim of the study was to assess the correlation between the levels of catecholamines and cerebral hemodynamics in patients with chronic post-traumatic stress disorder (PTSD). The study included 50 patients with chronic PTSD hospitalized for psychiatric treatment for the first time, and 50 healthy control subjects. All study subjects were in the 30-50 age group. In PTSD group, determination of vanllylmandelic acid (VMA), an epinephrine and norepinephrine metabolite, in 24-h urine and transcranial Doppler (TCD) sonography of the circle of Willis vasculature were performed on the first day of hospital stay. The same diagnostic procedures were repeated upon the completion of 21-day medicamentous psychiatric treatment. Initial analysis revealed concurrently elevated 24-h VMA in 29 (58.00%) patients and increased values of the mean blood flow velocity (MBFV) in the circle of Willis vasculature in 34 (68.00%) patients, indicating a high correlation of the respective parameters (p = 0.3290). Second analysis performed after 21-day psychiatric treatment showed concurrently elevated 24-h VMA in eight (16.00%) patients and increased MBFV in the circle of Willis vasculature in nine (18.00%) patients, also pointing to a high correlation of the parameters observed (p = 0.7906). In the control group, only two (4.00%) subjects had elevated MBFV in the circle of Willis vessels, whereas the level of 24-h VMA was normal in all control subjects. Study results pointed to a significant association between elevated levels of stress hormones and increased MBFV in the circle of Willis vasculature caused by cerebral vasospasm. Medicamentous psychiatric treatment for PTSD administered for three weeks significantly reduced the proportion of PTSD patients with elevated levels of the catecholamine metabolite and cerebral vasospasm. Study results showed a high correlation between diurnal VMA level and elevated MBFV in the circle of Willis vessels, clearly demonstrating the effect of prolonged elevation of catecholamine levels on cerebral hemodynamics.     

One-dimensional and three-dimensional models of cerebrovascular flow

The Circle of Willis is a ring-like structure of blood vessels found beneath the hypothalamus at the base of the brain. Its main function is to distribute oxygen-rich arterial blood to the cerebral mass. One-dimensional (1D) and three-dimensional (3D) computational fluid dynamics (CFD) models of the Circle of Willis have been created to provide a simulation tool which can potentially be used to identify at-risk cerebral arterial geometries and conditions and replicate clinical scenarios, such as occlusions in afferent arteries and absent circulus vessels. Both models capture cerebral haemodynamic autoregulation using a proportional-integral (PI) controller to modify efferent artery resistances to maintain optimal efferent flow rates for a given circle geometry and afferent blood pressure. The models can be used to identify at-risk cerebral arterial geometries and conditions prior to surgery or other clinical procedures. The 1D model is particularly relevant in this instance, with its fast solution time suitable for real-time clinical decisions. Results show the excellent correlation between models for the transient efferent flux profile. The assumption of strictly Poiseuille flow in the 1D model allows more flow through the geometrically extreme communicating arteries than the 3D model. This discrepancy was overcome by increasing the resistance to flow in the anterior communicating artery in the 1D model to better match the resistance seen in the 3D results.     

Willis环状脑动脉瘤生物数学模型的无结周期解与拟周期解

本文证明了Wi1lis环状脑动脉瘤生物数学模型：x~" ax-βx~2 yx~3＝Fcoswt（其中α,β,y,F,ω均为正常数）存在无穷多个以2mπω（m为大于1的整数）为最小周期的无结周期解和无穷多个拟周期解．