颅内动脉瘤动物模型的最新进展和应用

颅内动脉瘤足蛛网膜下腔出血的主要原因,致死率和致残率都很高,其破裂风险分析研究依赖所制备的真实可靠的动脉瘤动物模型.探讨动脉瘤的形态、病生理、演变过程,建立颅内动脉瘤动物模型,探索其发病机制,对临床治疗具有重要意义.本文对建立动脉瘤模型的几种方法进行了比较评述,并在此基础上提出了一种新的颅内动脉瘤动物模型的制作方法.     

基于CT的脑动脉瘤三维重建的有限元模型

目的建立脑动脉瘤三维重建的有限元模型,为临床脑动脉瘤破裂力学机制分析提供基础。方法依据临床脑动脉瘤患者CT数据,结合MIMICS 8.1数字化医学影像处理软件,运用三维重建技术构造脑动脉瘤的实体结构,最后导入ANSYS有限元通用软件完成脑动脉瘤的有限元建模与力学分析。结果建立临床上适用于脑动脉瘤患者血流动力学分析的有限元模型。结论模型具有数字化、个性化特征,可用于脑动脉瘤血流动力学性能计算,分析临床脑动脉瘤患者动脉瘤的破裂机制。     

个体化颈动脉瘤的血流动力学特性分析

目的 构建个体化的流固耦合模型,计算分析不同血液特性对动脉瘤腔内血液动力学的影响,进一步探讨对脑动脉瘤破裂的影响.方法 首先采集3D数字剪影图像构建动脉瘤模型,通过流体动力学计算方法分析在相同边界条件下,不同血流特性对颈动脉瘤动力学参数的影响.最后对简化颈动脉瘤实验模型进行粒子图像测试(particle image v...     

目录

近年来,计算流体力学（computational fluid dynamics, CFD）被广泛应用于脑动脉瘤的基础和临床研究中,其研究方向涉及：① 动脉瘤的形成、生长机制和动脉瘤破裂的血流动力学危险因素,② 通过建立患者个性化模型,评估弹簧圈和支架置入后动脉瘤内流场的变化,评价血管内治疗的效果。从计算流体力学模型的建立、评估动脉瘤破裂风险的形态和血流动力学参数、血流动力学参数评估动脉瘤治疗的手术效果3个方面详细阐述近年来在脑动脉瘤的诊治中血流动力学研究的进展。     

计算流体力学在脑动脉瘤诊治中的应用

近年来,计算流体力学(computational fluid dynamics,CFD)被广泛应用于脑动脉瘤的基础和临床研究中,其研究方向涉及:1动脉瘤的形成、生长机制和动脉瘤破裂的血流动力学危险因素,2通过建立患者个性化模型,评估弹簧圈和支架置入后动脉瘤内流场的变化,评价血管内治疗的效果。从计算流体力学模型的建立、评估动脉瘤破裂风险的形态和血流动力学参数以及血流动力学参数评估动脉瘤治疗的手术效果3个方面详细阐述近年来在脑动脉瘤的诊治中血流动力学研究的进展。     

可实现特殊网格划分的个性化动脉瘤实体模型的构建

目的　通过建立一个可以用于有限元分析,可进行分区域网格划分的个性化主动脉弓动脉瘤实体模型,探索一种能满足特殊网格划分要求的个性化实体模型的建立方法。方法　采用逆向工程的思想方法,借助Geomagic和Pro/E软件,以原始STL格式的表面模型为依据,建立了一个个性化主动脉弓动脉瘤实体模型,并加入理想化支架模型,导入ANSYS有限元分析软件最终完成实体模型的建立和分块。结果　建立的有限元模型,可进行针对边界层和支架的分区域网格划分,并完成了一个血流动力学模拟仿真。结论　建立的模型基本满足对特定区域网格细划分的需要,可以为支架介入治疗动脉瘤的血流动力学仿真提供基础。所建模型的方法是可行的,可以为将来建立其他类似模型提供参考。     

利用力学方法建立囊状动脉瘤动物模型

目的 提出一种力学方法,并设计一套实验装置建立囊状动脉瘤动物模型.方法 将自行设计的动脉瘤模具通过外科手术方式固定于兔腹主动脉上,通过负压吸引增大跨壁压差使动脉局部发生形变,从而形成囊状动脉瘤.结果 建立了形态学、组织学和病理学仿真的囊状动脉瘤动物模型,并且获得3枚囊状动脉瘤.结论 建立囊状动脉瘤动物模犁的力学方法是可行的,而且这套自行设计的实验装置具有实用性和有效性.     

支架治疗主动脉弓内侧动脉瘤的仿真研究

血管内支架是治疗主动脉弓动脉瘤的一种新技术。目前还没有人对具有局部突起的动脉瘤支架治疗血流动力学进行过研究。基于这样的事实,本仿真研究对主动脉弓内侧动脉瘤的支架治疗进行血流动力学分析。为便于比较,分别建立了有支架和无支架的主动脉弓动脉瘤模型。利用计算流体力学的方法对两个模型中的生理性血液流动进行了仿真。对流动情形、压力和壁面切应力分布进行了比较和分析,以便评价血管内支架对主动脉弓动脉瘤治疗的效果。结果表明,有支架的模型和无支架的模型,在瘤腔内的流动情形具有显著的不同。有支架模型瘤腔内的流动受到明显的抑制,特别是局部突起处的压力和壁面切应力大大地减小了。这些现象使我们有理由推断,血管内支架可以促进瘤腔内血栓的形成,并能减小动脉瘤破裂的危险。     

脑动脉瘤体外模拟实验

为了解释血液动力学参数对脑动脉瘤的生长、发育和破裂过程的影响 ,人们作了很多体外模型实验 ,利用激光多普勒测速仪 ( LDV)测量动脉瘤模型内的速度场 ,寻找诸如速度分布、压力分布以及壁面剪切力等动力学参数对动脉瘤的影响。本文回顾了这方面的一些工作 ,总结了几种形状的动脉瘤模型中的流场情况以及影响动脉瘤发育的一些因素     

支架介入治疗颈内动脉狭窄和动脉瘤对动脉瘤壁面压力的影响

目的研究当狭窄与动脉瘤毗邻时,使用支架介入治疗后对动脉瘤壁面压力产生的影响。方法使用计算流体动力学分析的方法对动脉瘤模型及狭窄和动脉瘤毗邻的模型进行对比研究。构建3个模型(M1、M2、M3)对压力变化进行分析比较。M1是颈内动脉瘤模型(无狭窄、无支架),在M1中的动脉瘤前构造一段狭窄动脉形成M2,在M2的动脉瘤部位植入支架后形成M3。结果 M2、M1两个模型相比较,轻度狭窄(50%)引起的动脉瘤部位的压力增加约为1.369 9 kPa(10.3 mmHg)(收缩期的峰值时刻),一个心动周期内动脉瘤部位的平均压力增加约为0.572 kPa(4.3 mmHg)。M3、M2两个模型相比较,动脉瘤部位的压力增加大约为1.037 kPa(7.8 mmHg)(收缩期的峰值时刻),一个心动周期内动脉瘤部位的平均压力增加大约为0.399 kPa(3 mmHg)。结论当使用支架治疗狭窄与弯曲颅内动脉瘤毗邻的患者时,轻度狭窄不会导致显著压力增加。载瘤动脉的形状、动脉瘤或动脉狭窄疾病确实对动脉瘤部位压力变化有影响。     

Fibrinolytic activity in aneurysmal bone cysts.

Euglobulin fibrinolytic activity of cyst fluid from six patients with aneurysmal bone cysys was considerably higher than that of arterial and venous blood of the corresponding patients. The high fibrinolytic activity was associated with a very low concentration of fibrinogen and a low concentration of plasminogen. Correspondingly, a high plasminogen activator activity was found in cyst tissue related to endothelial lining. It is suggested that fibrinolysis is an important factor in the maintenance and expansion of the aneurysmal bone cyst.     

Coagulation abnormalities in stroke--disseminated intravascular coagulation as a complication of subarachnoid hemorrhage

To determine the pathogenesis of the symptomatic vasospasm (SV) following subarachnoid hemorrhage (SAH), we compared the difference in coagulation activity between 52 aneurysmal patients with SV and 20 patients without SV. The hypercoagulable state was scored according to the Disseminated Intravascular Coagulation (DIC) scoring system. Our clinical studies showed that severe SAH following aneurysmal rupture caused the hypercoagulable state and there was a good correlation between the degree of the hypercoagulable state, the severity of SV and outcome of the aneurysmal patients. We stressed in this report that the monitoring of the blood coagulation and fibrinolytic activities is very important in severe SAH and that the hypercoagulable state after SAH plays an important role on the occurrence of SV.     

Endothelium in aneurysmal bone cyst

The surface of the large cystic spaces and dilated blood vessels in seven cases of aneurysmal bone cysts was studied. The endothelium of the blood vessels was surrounded by a layer of collagen types IV and V, and the endothelial cells contained factor VIII related antigen demonstrated by the peroxidase anti-peroxidase technique. Some blood vessels were dilated resembling small aneurysmal spaces. The visible surfaces of the aneurysmal spaces were devoid of collagen types IV and V, and of factor VIII related antigen. Ultrastructural analysis of paraffin embedded sections did not show the characteristic fine structural features of endothelium covering the aneurysmal spaces. It is concluded that the large spaces in aneurysmal bone cysts are devoid of basement membranes and endothelial cells. The absence of endothelium may explain the abundance of haemorrhages in these lesions. Immunocytochemical demonstration of endothelial antigen provides a valuable tool for the differential diagnosis between aneurysmal bone cysts and vascular tumours.     

ATP Transport in Saccular Cerebral Aneurysms at Arterial Bends

ATP acts as an extracellular signaling molecule in purinergic signaling that regulates vascular tone. ATP binds purinergic P2 nucleotide receptors on endothelial cells. Understanding the mass transport of ATP to endothelial cells by blood flow is thus important to predict functional changes in aneurysmal walls. While some clinical observations indicate a difference of wall pathology between ruptured and unruptured aneurysms, no study has focused on the mass transport in aneurysms. We investigated the characteristics of ATP concentration at aneurysmal wall using a numerical model of ATP transport in aneurysms formed at arterial bends. The magnitude of ATP concentration at the aneurysmal wall was significantly smaller than that at the arterial wall. In particular, significantly low concentration was predicted at the proximal side of the aneurysmal sac. A strong correlation was revealed between the inflow flux at the aneurysmal neck and the resultant concentration at the aneurysmal wall.     

A small aneurysmal bone cyst restricted to the cortical bone of the femur resembling so-called subperiosteal giant cell tumor or subperiosteal osteoclasia

We report a 16-year-old Japanese girl with a cystic lesion restricted to the cortical bone under the periosteum of the diaphysis of the left femur. Roentgenograms showed a long, oval translucent lesion in frontal view and an eccentric erosive lesion in lateral view. Computed tomography showed a distinct intracortical lesion. The lesion, which was excised en bloc, measured 3 x 2 x 2 cm. The outer layer of the cortical bone was eroded eccentrically. From the margin of the eroded bone, thin fragile bony tissue and preserved periosteum extended like the roof of a dome. Multicystic structures, filled with blood, were lined with fibrous granulation and occasional giant cells. Histologically, this lesion falls within the category of aneurysmal bone cyst. However this case is of a rare type, since the lesion was relatively small, and showed a very specific intracortical location, in marked contrast to typical aneurysmal bone cyst. Additionally, this lesion is similar to so-called subperiosteal giant cell tumor or subperiosteal osteoclasia described in the literature.     

Fine needle aspiration cytology diagnosis of aneurysmal bone cyst: a case report

Aneurysmal bone cyst is a relatively rare tumour accounting 1 to 6% of all primary bone tumours. The involvement of clavicle is even rare with incidence of only 3% of all cases of aneurysmal bone cyst. Aneurysmal bone cyst is an expanding osteolytic lesion occurring mostly at metaphyseal ends of the long bones. Although excisional biopsy is diagnostic for aneurysmal bone cyst and FNAC (fine needle aspiration cytology) is mostly inconclusive. Still FNAC can be helpful in pre-operative diagnosis of aneurysmal bone cyst.     

"Solid" variant of aneurysmal bone cyst.

A case of the so-called "solid" variant of aneurysmal bone cyst is reported. A 12-year-old girl with a few weeks' history of backache presented with a tender palpable mass located thoraco-spinal in the back at Th 3. Radiologically, the lesion was consistent with conventional aneurysmal bone cyst. Morphologically, it showed fibroblastic, fibrohistiocytic, fibromyxoid, osteoclastic and osteoblastic components as well as small aneurysmal sinusoids. Based on four other well documented cases, the clinico-pathological features and the differential diagnostical problems are discussed.     

Quantitative Effects of Coil Packing Density on Cerebral Aneurysm Fluid Dynamics: An <Emphasis Type="Italic">In Vitro</Emphasis> Steady Flow Study

Over the past 15 years, coil embolization has emerged as an effective treatment option for cerebral aneurysms that is far less invasive than the long-standing convention of surgical clipping. However, aneurysm recurrence after coil embolization is not uncommon: recurrence rates as high as 50% have been reported in the literature. One factor that may contribute to recurrence after coiling is residual flow into the aneurysmal sac. At present, there is limited quantitative knowledge of the relationship between coil packing density and aneurysmal inflow. We present an in vitro fluid dynamic study of basilar tip aneurysm models that elucidates this relationship. At physiologically normal flow rates, we found that a packing density of 28.4% decreased aneurysmal inflow by 31.6% in a wide-neck model, and that a packing density of 36.5% decreased aneurysmal inflow by 49.6% in a narrow-neck model. Results also indicated that coiling reduced aneurysmal inflow more significantly at lower parent vessel flow rates, and that coiling reduced neck-plane velocity magnitudes more significantly for narrow-neck aneurysms. Our study provides novel quantitative information that could ultimately contribute to improved outcomes for patients with cerebral aneurysms by enabling more effective coil embolization.     

A Small Aneurysmal Bone Cyst Restricted to the Cortical Bone of the Femur Resembling So-called Subperiosteal Giant Cell Tumor or Subperiosteal Osteoclasia

We report a 16-year-old Japanese girl with a cystic lesion restricted to the cortical bone under the periosteum of the diaphysis of the left femur. Roentgenograms showed a long, oval translucent lesion in frontal view and an eccentric erosive lesion in lateral view. Computed tomography showed a distinct intracortical lesion. The lesion, which was excised en bloc , measured 3×2×2 cm. The outer layer of the cortical bone was eroded eccentrically. From the margin of the eroded bone, thin fragile bony tissue and preserved periosteum extended like the roof of a dome. Multicystic structures, filled with blood, were lined with fibrous granulation and occasional giant cells. Histologically, this lesion falls within the category of aneurysmal bone cyst. However this case is of a rare type, since the lesion was relatively small, and showed a very specific intracortical location, in marked contrast to typical aneurysmal bone cyst. Additionally, this lesion is similar to so-called subperiosteal giant cell tumor or subperiosteal osteoclasia described in the literature. Acta Pathol. Jpn. 39: 539∼544, 1989.