椎-基动脉延长扩张症的磁共振成像和磁共振血管造影

椎-基动脉延长扩张症(VBD)是一种依据神经放射学检查诊断的椎-基底动脉伸长和扩张症。根据 Smoker定义:VBD一词只适用于基底动脉位于小脑桥脑角斜坡外缘或鞍上池上方,且其直径大于4.5mm者。 由于VBD与临床症状之间缺乏明确关系,无论损伤性血管造影或极少损伤的CT增强与磁共振成像(MRI)都易出现误诊。目前已可常规采用MRI合用无损伤性磁共振血管造影(MRA)技术,借助血流中的磁性进行诊断。     

椎基底动脉延长扩张症与缺血性脑卒中经颅多普勒超声特点及临床预后

目的探讨缺血性脑卒中患者合并椎基底动脉延长扩张症的血流动力学特点及对临床预后的影响。方法回顾性分析年龄≥65岁的急性缺血性脑卒中患者239例,依据影像学表现判断椎基底动脉延长扩张症(VBD),分为VBD组和非VBD组。观察两组血流动力学特点。结果VBD与非VBD组基底动脉的平均血流速度(MFV)和搏动指数(PI值)差异有统计学意义。两组病后24 h内1、3、6个月美国国立卫生研究所脑卒中量表(NIHSS)评分差异有统计学意义。结论 VBD患者后循环血流速度慢,且动脉搏动减弱。VBD患者在发生缺血性脑卒中时神经功能损伤程度较重,且恢复程度慢。     

大型未破裂颅内动脉瘤的血流动力学特点分析

目的探讨大型未破裂颅内动脉瘤的血流动力学特点。方法结合数字减影血管造影（DSA）三维图像,采用计算流体力学（CFD）有限元方法的软件,对12例直径≥15mm的未破裂颅内动脉瘤进行数值模拟,对其血流动力学参数进行分析,并与其载瘤动脉上的参数相对比。结果大型动脉瘤内部涡流形态复杂,在主要涡流内部有大面积紊乱的低速流动。动脉瘤瘤颈处速度最大,瘤顶附近存在一个面积较大的低流速区,流速接近0;与其载瘤动脉相比,收缩期末平均壁面切应力（WSS）显著降低,平均切应力震荡因子（OSI）显著增高,瘤壁平均低WSS面积百分比为24．74％。结论未破裂大型动脉瘤的血流动力学特点为紊乱的涡流、瘤顶附近较大面积的低流速区、瘤壁高OSI和大面积的低wSS区。     

冠状动脉狭窄对血管血流动力学的影响

目的运用计算流体动力学技术,模拟冠状动脉不同狭窄程度的血流动力学变化,探索冠状动脉血流动力学变化和血流分布与冠状动脉不同狭窄病变的关系。方法以正常人右冠状动脉CT图像数据为基础,重建冠状动脉几何模型,人工建立狭窄程度分别为0%(正常)、30%(轻度狭窄)、60%(中度狭窄)和90%(重度狭窄)的4种血管模型,并分别构建血管血流动力学模型,最后分别进行数值模拟,分析比较4种血管模型血流动力学的差别。结果通过比较4种血管模型的血流动力学数值模拟可发现,随着冠状动脉狭窄程度增加,狭窄远心端血流涡旋愈加明显,狭窄处血流速度以及狭窄前血管壁面压力(WP)逐渐增加,而狭窄远心端WP逐渐下降;狭窄处壁面切应力(WSS)分布一直处于高值,并且当血管狭窄程度达到中重度狭窄,狭窄远心端血管可见明显的高WSS区域,而狭窄远心端血管其他区域呈现低WSS;狭窄前后血管血流速度以及血流分布也发生了改变。结论在CT图像上,可能能较准确重建出冠状动脉血流动力学模型,并模拟出不同狭窄程度冠状动脉模型。中重度冠状动脉狭窄远心端血流动力学表现为明显的血流涡旋以及高WSS区域,这种血流动力学变化可能会加重血管动脉粥样硬化,从而进一步加重血管狭窄。     

CTA、MRA对椎基底动脉供血不足诊断价值初探

对临床确诊椎基底动脉供血不足患者52例进行颅脑多层螺旋CT血管成像(CTA)、磁共振血管成像(MRA)检查.发现颅脑CTA检查的阳性率为90%,MRA阳性率为56%,二者均能很好地显示椎动脉的整体形态.提示CTA、MRA检查是椎基底动脉供血不足患者有价值的客观检查手段.     

磁共振对椎基底动脉延长扩张症的诊断价值分析

目的探讨椎基底延长扩张症临床表现与MRI及MRA的影像特点,以提高磁共振在椎基底动脉延长扩张症(VBD)检查、诊断中的重要性。方法分析30例病人的临床症状及影像表现。结果三叉神经受累7例,面神经受累8例,听神经受累2例,后循环梗死脑实质受累型5例,后循环供血不足6例,脑出血6例,脑积水1例。所有病人直径扩张超过4.5mm,椎动脉颅内段长度超过23.5mm,基底动脉长度超过30mm,所有病人均有明显偏移,15例向右侧偏移,8例向左侧偏移。结论 MRI及MRA可显示椎基底动脉形态及与邻近组织的解剖关系,对椎基底动脉扩张延长症诊断提供直观依据。     

椎动脉迂曲对脑血流动力学影响的临床研究

目的 探讨椎动脉迂曲对脑血流动力学的影响.方法 对223例椎-基底动脉短暂性脑缺血发作(TIA)患者行脑血管造影术,筛选出椎动脉迂曲患者,经颅彩色多普勒的方法对椎动脉血流动力学改变进行评价.结果 223例椎-基底动脉TIA患者中84名患者椎动脉迂曲;与无椎动脉迂曲组相比,椎动脉迂曲患者年龄更大,具有血管危险因素的比例更高;椎动脉迂曲患者,尤其在中重度椎动脉迂曲患者收缩期血流速度、平均血流速度低于对照组,而血管搏动指数及阻力指数均高于对照组.结论 椎动脉迂曲是椎-基底动脉TIA常见血管异常,并导致血流动力学改变,高龄和血管危险因素可能是导致椎动脉迂曲的因素.     

痰瘀同治法在椎-基底动脉供血不足中的应用

目的观察痰瘀同治法治疗椎-基底动脉供血不足的临床疗效,并探讨其作用机制.方法给50例椎-基底动脉供血不足病人口服痰瘀同治组方"三降汤",每日1剂,14 d为1个疗程.通过经颅多普勒超声(TCD)观察其用药前后椎-基底动脉系统供血情况.结果 50例椎-基底动脉供血不足病人临床症状基本消失或完全消失44例(88%),有改善6例(12%).TCD显示血流速度变化显著,血流缓慢组用药后3支动脉各项数值均较用药前有较大幅度提高(P＜0.01),血管狭窄组用药后过高的血流速度数值较用药前有所下降(P＜0.05).结论痰瘀同治法组方"三降汤"可改善椎-基底动脉供血不足的症状.     

无症状椎基底动脉延长扩张症患者的心血管疾病危险因素和神经影像学特征

目的对无症状椎基底动脉延长扩张症（VBD）受检者的心血管疾病（CVD）危险因素、神经影像学特征进行阐述。方法对无症状志愿受试者行磁共振成像（MRI）及磁共振血管造影（MRA）检查后,将其分为无症状VBD组及对照组,对两组间的CVD危险因素进行比较分析,对无症状VBD受试者基底动脉（BA）及椎动脉（VA）的直径、高度和水平位移等影像学特征进行分析。结果与对照组比较,无症状VBD组高血压、肥胖、吸烟、高血脂、糖尿病和有中风或心血管疾病家族史的发生率明显增加。无症状VBD组患者BA直径为（4.8±0.2）mm,1例BA存在严重延长及水平移位;小梗死灶14例,脑干受压1例,脑积水1例,脑囊状动脉瘤1例。结论无症状VBD受试者中男性居多,存在高血压、吸烟、CVD或脑卒中家族史等多项危险因素,且小梗死灶的发病率较高。     

支架置入治疗大脑中动脉瘤的数值模拟研究

目的探讨支架置入前、后,计算机数值模拟大脑中动脉分叉处动脉瘤的血流动力学变化。方法结合DSA影像,采用计算流体力学有限元方法的软件,对单纯使用支架治疗大脑中动脉分叉处未破裂动脉瘤的1例患者,在支架置入前及支架置人后9个月,行血管形态学特征和血流动力学数值模拟分析（包括血液流线、血管壁面压力和剪应力等）。从三维旋转造影图像数据中获得模型,将生理脉动流作为进入流,采用软件生成网格并计算非定常层流的连续动力方程。结果与支架置入前比较,支架置入后,①血管形态学发生了明显改变,大脑中动脉的M1段和M2段下干血管夹角变大（67．7°变为124．1°）,瘤体消失。②血流对瘤颈口冲击明显降低,改变动脉瘤内的压力,术前瘤顶平均壁面压力为977．06Pa,瘤颈处平均壁面压力为950．46Pa。支架置人后消除了瘤颈处的高壁面压力区域,9个月时复查该处平均壁面压力为831．31Pa。③改善动脉瘤表面的壁面切应力（WSS）分布,术前瘤顶区域的平均WSS为2．09Pa,瘤颈区域的平均WSS为7．51Pa,9个月复查时变得渐趋一致。结论血管内单纯支架置人通过对血管形态学的改变,引起血流动力学变化可能是使动脉瘤愈合的机制。     

Effects of arterial blood flow on walls of the abdominal aorta: distributions of wall shear stress and oscillatory shear index determined by phase-contrast magnetic resonance imaging

Although abdominal aortic aneurysms (AAAs) occur mostly inferior to the renal artery, the mechanism of the development of AAA in relation to its specific location is not yet clearly understood. The objective of this study was to evaluate the hypothesis that even healthy volunteers may manifest specific flow characteristics of blood flow and alter wall shear or oscillatory shear stress in the areas where AAAs commonly develop. Eight healthy male volunteers were enrolled in this prospective study, aged from 24 to 27. Phase-contrast magnetic resonance imaging (MRI) was performed with electrocardiographic triggering. Flow-sensitive four-dimensional MR imaging of the abdominal aorta, with three-directional velocity encoding, including simple morphological image acquisition, was performed. Information on specific locations on the aortic wall was applied to the flow encodes to calculate wall shear stress (WSS) and oscillatory shear index (OSI). While time-framed WSS showed the highest peak of 1.14 ± 0.25 Pa in the juxtaposition of the renal artery, the WSS plateaued to 0.61 Pa at the anterior wall of the abdominal aorta. The OSI peaked distal to the renal arteries at the posterior wall of the abdominal aorta of 0.249 ± 0.148, and was constantly elevated in the whole abdominal aorta at more than 0.14. All subjects were found to have elevated OSI in regions where AAAs commonly occur. These findings indicate that areas of constant peaked oscillatory shear stress in the infra-renal aorta may be one of the factors that lead to morphological changes over time, even in healthy individuals.     

椎基底动脉延长扩张症患者的临床特点

 目的 研究椎基底动脉延长扩张症(VBD)患者的临床特点。方法 连续收集2008年10月至2012年2月确诊的VBD患者27例设为VBD组,并设置同期临床表现相似的非VBD脑血管病患者81例为对照组,分析VBD的危险因素、脑血流动力学特点,并总结神经影像学和临床表现特征。 结果 (1)两组患者间在血脂水平及合并基础心脑血管疾病上差异有统计学意义(P<0.05);(2)VBD患者的脑血流动力学特征主要表现为椎基底动脉收缩期峰值血流速度减慢,收缩/舒张比值降低,VBD组和对照组的峰值平均血流速度(-27±9比-40±15)、搏动指数(0.38±0.15比0.78±0.19)、阻力指数(0.48±0.23比0.88±0.18)比较差异均有统计学意义(P值分别为0.036、0.032、0.032);(3)VBD患者临床主要表现为脑梗死,以后循环微小梗死为主,其次表现为脑出血、对周边组织的压迫症状和体征、脑积水等,多合并出现,经MRI检查多可确诊。结论 VBD患者具有相对特异的临床特征,MRI 检查为首选。     

颅内后交通动脉动脉瘤栓塞后复发的血流动力学数值模拟分析

目的采用血流动力学数值模拟的方法探讨颅内后交通动脉动脉瘤(PCoA-An)栓塞前后的血流动力学特点及其对栓塞术后复发的影响。方法连续纳入2008年1月—2010年2月行栓塞治疗的PCoA-An患者13例,根据随访的结果将其分为复发组4例和稳定组9例。基于栓塞前后的三维脑血管造影资料建立动脉瘤模型,通过计算流体力学软件,采用有限元算法对术前及术后瘤颈区域的血流动力学特征进行分析,并评价其对动脉瘤复发(2～18个月)的影响。结果栓塞术前,复发组瘤颈区域的收缩峰期壁面切应力(WSS)和血流速度分别为(29±7)Pa和(0.62±0.12)m/s,稳定组分别为(31±12)Pa和(0.85±0.29)m/s,两组比较差异均无统计学意义,P>0.05。栓塞术后,复发组相同区域收缩峰期的WSS和血流速度分别为(48±4)Pa和(0.99±0.09)m/s,与术前比较均明显增高,P<0.05;稳定组分别为(21±12)Pa和(0.57±0.27)m/s,与术前比较均明显降低,P<0.05。栓塞术后,复发组瘤颈区域收缩峰期的WSS和血流速度均明显高于稳定组,差异有统计学意义,P<0.01,P<0.05。结论栓塞PCoA-An后,瘤颈区域存在的高WSS、高血流速度可能是导致术后动脉瘤复发的重要因素。     

头晕、眩晕患者行比颅多普勒超声检测的临床意义

对2159例头晕、眩晕患者进行经颅多普勒（TCD）检测,其中合并高血压269例,糖尿病58例。结果显示：①14.27%的患者血管狭窄,8.66%血流速度减慢;眩晕者椎动脉狭窄率明显于头晕者,二者有显著性差异。②老年患者颈内动脉系统狭窄和椎基底动脉系统血流速度降低较明显。③高血压、糖尿病与颅内血管狭窄有明显相关性。提示临床上不能把单纯眩晕、头晕患者诊断为功能性疾病或椎基底动脉供血不足。     

Computational Simulations Demonstrate Altered Wall Shear Stress in Aortic Coarctation Patients Treated by Resection with End‐to‐end Anastomosis

Background. Atherosclerotic plaque in the descending thoracic aorta (dAo) is related to altered wall shear stress (WSS) for normal patients. Resection with end‐to‐end anastomosis (RWEA) is the gold standard for coarctation of the aorta (CoA) repair, but may lead to altered WSS indices that contribute to morbidity. Methods. Computational fluid dynamics (CFD) models were created from imaging and blood pressure data for control subjects and age‐ and gender‐matched CoA patients treated by RWEA (four males, two females, 15 ± 8 years). CFD analysis incorporated downstream vascular resistance and compliance to generate blood flow velocity, time‐averaged WSS (TAWSS), and oscillatory shear index (OSI) results. These indices were quantified longitudinally and circumferentially in the dAo, and several visualization methods were used to highlight regions of potential hemodynamic susceptibility. Results. The total dAo area exposed to subnormal TAWSS and OSI was similar between groups, but several statistically significant local differences were revealed. Control subjects experienced left‐handed rotating patterns of TAWSS and OSI down the dAo. TAWSS was elevated in CoA patients near the site of residual narrowings and OSI was elevated distally, particularly along the left dAo wall. Differences in WSS indices between groups were negligible more than 5 dAo diameters distal to the aortic arch. Conclusions. Localized differences in WSS indices within the dAo of CoA patients treated by RWEA suggest that plaque may form in unique locations influenced by the surgical repair. These regions can be visualized in familiar and intuitive ways allowing clinicians to track their contribution to morbidity in longitudinal studies.     

灯盏花素注射液治疗椎-基底动脉供血不足58例

目的探讨灯盏花素注射液治疗椎-基底动脉供血不足（VBI）的临床疗效.方法将102例VBI病人随机分为灯盏花素组（治疗组）和对照组.两组均口服尼莫地平片,治疗组加用灯盏花素注射液,连用1个疗程（10 d）后,评定疗效,并经颅多普勒超声（TCD）检测.结果治疗组疗效明显优于对照组（P〈0.05）.治疗后两组椎动脉（VA）、基底动脉（BA）、大脑后动脉（PCA）血流速度比较均有统计学意义（P〈0.01）.结论灯盏花素注射液是治疗VBI的有效药物.     

Relation between non-uniform hemodynamics and sites of altered permeability and lesion growth at the rabbit aorto-celiac junction

Using the rabbit's aorto-celiac junction as a representative atherosclerotic model, the hemodynamics of a bifurcating blood vessel are numerically simulated and three hemodynamic parameters are compared. The wall shear stress (WSS), the oscillatory shear index (OSI), and the spatial wall shear stress gradient (WSSG) are considered in this study. Locally enhanced wall permeabilities and intimal macrophages are generally considered to be involved in atherogenesis, and here the primary concern is with the hemodynamic influence on these early stages of the disease process. In comparing the segmental averages of the indicator functions and previously published intimal white blood cell densities, only the WSSG shows a statistically significant correlation. All three indicators have selective strengths in determining sites of early lesion growth around the aorto-celiac flow divider. At the proximal end of the flow divider on the lateral side of the orifice, there are elevated values of the OSI as well as WSSG and low WSS values. Regions of elevated wall permeabilities compare with the regions of elevated WSSG along the lateral and distal portions of the flow divider. Largely dependent upon the present input pulse with reverse flow, the OSI indicates relatively high values throughout the flow domain, however, it is important when utilized in conjunction with low WSS regions. This study presents a rationale for further quantitative correlative studies in the rabbit model based on additional histological data sets.     

血管内支架置入术治疗椎-基底动脉延长扩张症

目的探索使用血管内支架技术治疗椎-基底动脉延长扩张症（VBD）的可行性、有效性和安全性。方法回顾性分析2004年1月-2010年1月,上海第二军医大学长海医院神经外科采用血管内支架置入术治疗的5例VBD患者。结果①5例患者中,VBD合并椎-基底动脉急性夹层1例,VBD合并椎动脉动脉瘤1例,VBD引起三叉神经痛l例,VBD致后循环缺血、梗死2例。②每例VBD患者平均置入3（1～5）枚LEO支架和3．8（0～8）枚弹簧圈,重建椎-基底动脉的血流。③所有患者血管重建成功,术后症状均明显改善,未出现手术相关并发症。5例患者平均随访9．2（2～17）个月,无新发临床症状。结论弹簧圈辅助支架治疗VBD在技术上具有可行性,安全性较好,可显著改善VBD引起的多种临床症状,但对卒中的长期预防效果尚有待进一步研究。     

Viscosity-independent velocity of neutrophils rolling on p-selectin in vitro or in vivo

OBJECTIVE: To determine whether selectin-mediated leukocyte-rolling velocity in inflamed venules in vivo is determined by wall shear rate (WSR) or by wall shear stress (WSS). METHODS: WSS was manipulated independently of WSR by altering the viscosity of blood plasma in mice with an isovolemic exchange of blood for low- or high-viscosity dextran solutions. Rolling of neutrophils or beads coated with P-selectin glycoprotein ligand-1 (PSGL-1) was reconstituted on P-selectin immobilized on the wall of a parallel plate flow chamber at two different viscosities of the perfusion medium. RESULTS: Leukocytes in vivo showed no increase in rolling velocity when shear stress was doubled by doubling viscosity. Neutrophils in the parallel-plate flow chamber in vitro showed the same dependence on WSR as leukocytes in vivo, but bead-rolling velocities correlated best with WSS. Rolling leukocytes, but not beads, deformed significantly in shear flow, and deformation correlated better with WSS. CONCLUSION: These data suggest leukocyte deformation during rolling offsets increased bond breakage at higher shear stress. The stable rolling velocity allows sufficient surveillance of the endothelial surface, even in venules with high WSS. doi:10.1038/sj.mm.7800165