Radiologic evaluation of the carotid arteries

In recent years the radiologist has been faced with a host of new imaging modalities which provide structural as well as physiologic information about the carotid arteries. Although conventional intra-arterial angiography is considered the standard of comparison for precise anatomic definition of the cervical and intracranial carotid arteries, it is being replaced in many instances by other techniques. CT scanning may provide valuable information regarding the relationship of the carotid arteries to soft tissue structures in the neck, and dynamic CT scanning has been used to measure cerebral blood flow. Other noninvasive techniques, such as B-mode scanning and Doppler imaging and spectral analysis, can provide accurate information about carotid stenoses and occlusions, although mostly limited to the region of the common carotid bifurcation. The recent development of digital subtraction intravenous angiography provides a revolutionary new and safe way to evaluate the entire carotid arteries, from their origins to their intracranial branches. The advantages and disadvantages, as well as the current roles of these modalities in the radiologic evaluation of the carotid arteries, will be discussed.     

Blunt trauma to the carotid arteries

Carotid artery dissection is a rare occurrence in the trauma patient. Two cases of blunt trauma resulting in carotid artery dissection are reported. Initial recognition by clinicians is often difficult because of the diverse clinical manifestations, the delay in presentation, and the associated multi-organ system injuries that accompany carotid artery dissection. Because the diagnosis of carotid injury is rarely suspected in patients with neurological deficits, the first diagnostic test performed is usually computed tomography (CT) of the head. Angiography should be strongly considered when the following occur: (a) Neurologic deficits are incompatible with CT findings; (b) there is monoparesis or hemiparesis with a normal mental status examination; (c) there is severe cervical trauma with an abnormal neurological exam; or (d) a basilar skull fracture is present in a patient with an abnormal mental status exam. Once diagnosed, the management of carotid artery dissection is complex and no generalized guidelines have been established.     

Doppler-ophthalmomanometry in patients with obstruction of the carotid arteries

A novel noninvasive method to determine simultaneously ophthalmic artery pressure (OAP) and flow direction based on Doppler ultrasound principles is presented: ophthalmomanometry-Doppler (OMD). Studies performed on 25 angiographically proven normal subjects with direct recording of the internal carotid artery pressure (ICP) and indirect determination of the brachial artery pressure (BAP) demonstrated that OAP values assessed by the OMD device are highly correlated with simultaneous ipsilateral intraarterial systolic ICP measurements (r = 0.95, n = 10) and with simultaneous recordings of the BAP (r = 0.88, n = 15). In 50 patients presenting angiographically occlusions and 52 patients presenting angiographically stenoses (greater than 60%) of the carotid artery the measured Doppler ophthalmic pressure index (OPI = ratio of the ophthalmic to systemic blood pressure) was lower ipsilateral to an occlusion (0.46 +/- 0.08) than ipsilateral to a stenosis (0.54 +/- 0.08; p less than 0.001) of the carotid artery. In both it was clearly diminished compared to normal values (0.68 +/- 0.04; p less than 0.001). In carotid artery occlusions, the ipsilateral OPI was 0.46 +/- 0.06 for antegrade (n = 17) and 0.46 +/- 0.09 for retrograde (n = 28) ophthalmic artery flow. In carotid artery stenoses, the ipsilateral OPI was 0.55 +/- 0.07 for antegrade (n = 41) and 0.48 +/- 0.06 for retrograde (n = 9) ophthalmic artery flow (p less than 0.01). It is concluded that in carotid occlusions presenting a longer disease history extra-intracranial collateralisation via the ophthalmic artery are as efficient as a functional circle of Willis.     

颈内动脉系统血管内治疗技术的临床探讨

目的 探讨颈内动脉系统血管内治疗技术与效果。方法 采用股动脉入路、颈内动脉选择性插管的方法,行脑癌区域性化疗5例、CCF栓塞治疗6例共14次。治疗前先行全脑血管造影,CCF加行压颈功能试验。结果 14例次颈内动脉介入操作技术成功率为100％,无任何严重并发症;所有患治疗后均症状缓解或消失。脑癌介入化疗后均有瘤体缩小和瘤周水肿减轻改变。6例CCF球囊栓塞后5例达到影像学痊愈且保持了人动脉通畅;1例瘘口巨大同时闭塞了颈内动脉。结论 颈内动脉介入性脑癌化疗及CCF闭塞术较为安全、有效。     

Color-SieScape imaging of carotid and vertebral arteries.

OBJECTIVE: The aim of this study was to estimate the feasibility and limitations of Color-SieScape imaging of carotid and vertebral arteries in healthy subjects. METHODS: extended field of view procedure was applied during the examination of 80 carotid and 80 vertebral arteries in 40 healthy volunteers. RESULTS: visualisation of a common carotid artery together with a proximal segment of both an internal (ICA) and external carotid artery (ECA) in one Color-SieScape image was possible in nine cases. Clear presentation of a common carotid artery in one Color-SieScape image with a segment of an ICA or ECA of varying length was possible in 49 cases. In 22 cases, visualisation of an ICA was possible only on a minimal length, with major artefacts or completely impossible. Color-SieScape images of vertebral arteries were good or very good in 34 cases and poor or very poor in 46 cases. Artefacts arose due to the pulsatile movements of the arterial wall, especially in vessels lying close to the skin and in the proximal part of a common carotid artery. Tracing a tortuous vessel and ICA coming from common carotid artery at an angle close to 90 degrees produced significant artefacts. CONCLUSIONS: Color-SieScape images of carotid and vertebral arteries of good quality are usually possible to obtain.     

The development of hemodynamics in the extracranial carotid and vertebral arteries

To investigate the development of hemodynamics in the extracranial carotid and vertebral artery system, a prospective color duplex sonography study was performed in 94 healthy children and adolescents between 3 and 18 y old. Angle-corrected flow velocities and luminal diameters were measured; waveform parameters and flow volumes were calculated. Side-to-side differences of volumetric data were analyzed. In 53 children, an intrasession test-retest flowmetry of the internal carotid and vertebral arteries was performed. From 3 to 18 y old, flow volumes decreased significantly in the vertebral arteries (p ≤ 0.01) and increased in the external carotid artery (p ≤ 0.0001); the luminal diameter increased in all the carotid arteries (p ≤ 0.0001) and remained constant in the vertebral arteries; mean flow velocities declined in the common and internal carotid arteries and in the vertebral arteries (p ≤ 0.0001), but increased in the external carotid arteries (p ≤ 0.01). Flow volume rate was lower in the right than the left vertebral artery (p ≤ 0.0001), and there was no side difference in any of the carotid arteries. The test-retest correlation of volumetric data was high (0.81 ≤ r ≤ 0.97; p ≤ 0.0001). By comparing the reference data presented here with analogous adult data, we were able to delineate the physiologic development of extracranial and cerebral hemodynamics from childhood to adulthood. These data make possible the clinical application of quantitative flowmetry in extracranial cerebral arteries of children and adolescents.     

颈动脉超声检测对冠心病及其危险因素的临床意义

目的探讨颈动脉超声检查结果与冠心病及其危险因素的临床关系。方法研究对象经选择性冠状动脉造影(CAG)分为单支病变组、双支病变组和三支病变组,观察冠心病危险因素与冠状动脉病变支数、颈动脉超声的关系以及CAG结果与颈动脉超声的关系。结果三支病变组收缩压、脉压、总胆固醇、血糖高于双支和单支病变组(P<0.05);高危险因素组颈动脉内-中膜厚度(IMT)、阻力指数(RI)明显大于低危险因素组(P<0.05);三支病变组IMT与斑块指数(PI)高于双支和单支病变组(P<0.05)。结论颈动脉超声检查可预测冠状动脉病变的严重程度和筛查冠心病的高危患者。     

Flow-area relationship in internal carotid and vertebral arteries

Subject-specific computational and experimental models of hemodynamics in cerebral aneurysms require the specification of physiologic flow conditions. Because patient-specific flow data are not always available, researchers have used 'typical' or population average flow rates and waveforms. However, in order to be able to compare the magnitude of hemodynamic variables between different aneurysms or groups of aneurysms (e.g. ruptured versus unruptured) it is necessary to scale the flow rates to the area of the inflow artery. In this work, a relationship between flow rates and vessel areas is derived from phase-contrast magnetic resonance measurements in the internal carotid arteries and vertebral arteries of normal subjects.     

颈动脉血管重构特征在自发性高血压大鼠体内的表现

目的:血管重构是高血压的重要病理变化,是高血压导致器官损害的结构基础。实验观察自发性高血压大鼠颈动脉中层组织学的相关变化,以验证血管重构的特点。方法:实验于2006-06/2007-03在福建医科大学附属协和医院心血管内科实验室完成。①实验材料及分组:12周龄雄性自发性高血压大鼠10只,同性别周龄的WKY大鼠10只为对照,喂养18周后终止实验。②实验过程及评估:开始及每2周测鼠尾收缩压。实验结束后,麻醉后取颈动脉,行苏木精-伊红、苦味酸-天狼星红、弹力纤维和胶原纤维的双重染色(P/VB法),利用计算机辅助成像系统测算颈动脉中膜厚度、腔径、血管中膜厚/腔径、中膜横截面积、中膜细胞平均核面积及中膜的胶原面积百分比、弹性纤维面积百分比、弹性纤维面积与胶原面积的比值。SP免疫组织化学染色检测α-平滑肌肌动蛋白、增殖细胞核抗原、纤维粘连蛋白、层粘连蛋白等抗原在颈动脉壁的表达,并计算颈动脉中膜细胞增殖指数;以原位末端标记法标记血管壁的凋亡细胞,计算颈动脉中膜细胞凋亡指数。结果:20只大鼠全部进入结果分析。①自发性高血压大鼠实验开始和结束前的收缩压均>150mmHg,高于WKY大鼠(P<0.01)。②自发性高血压大鼠颈动脉中膜厚度、腔径、中膜厚度/腔径、中膜横截面积、中膜胶原面积百分比均高于WKY大鼠(P<0.01),而中膜弹性纤维面积百分比、弹性纤维面积与胶原面积比值均低于WKY大鼠(P<0.01)。③α-平滑肌肌动蛋白在两组大鼠颈动脉中膜均可表达,提示中膜细胞为血管平滑肌细胞。④自发性高血压大鼠中膜血管平滑肌细胞平均核面积大于WKY大鼠(P<0.01),中膜细胞增殖指数与WKY大鼠差异无显著性(P>0.05),中膜细胞凋亡指数显著低于WKY大鼠(P<0.01)。⑤自发性高血压大鼠颈动脉中膜纤维粘连蛋白、层粘连蛋白的光密度值(IA值)及染色阳性面积百分比高于WKY大鼠(P<0.01)。⑥颈动脉中膜血管平滑肌细胞凋亡指数与中膜横截面积呈显著负相关(r=-0.872,P<0.01);纤维连接蛋白表达的吸光度值与中膜横截面积呈显著正相关(r=0.954,P<0.01)。结论:自发性高血压大鼠颈动脉存在明显的重构,其特点为中膜肥厚、平滑肌细胞肥大、凋亡减少及胶原、纤维粘连蛋白、层粘连蛋白的过度沉积。     

Duplex ultrasound analysis of operated carotid arteries in baboons

Duplex ultrasound analysis, which combines high-resolution B-mode imaging and Doppler spectral flow analysis, was used to examine 3 to 4 mm in diameter normal [n = 24] and mechanically manipulated baboon carotid arteries (endarterectomies [n = 10], construction of interposition vascular grafts [n = 10], and placement of endovascular stents within interposition grafts [n = 4]). Patency or occlusion was definitively confirmed by direct visualization and palpation during surgical exploration at defined intervals or by postmortem histologic examination. Duplex examination accurately demonstrated postoperative hemodynamic changes and with only one exception correctly identified patency and occlusion. We conclude that this technique is superior to more invasive methods for verification of the outcome of operations on small arteries in experimental animals.     

糖尿病患者颈动脉超声改变的相关性研究

目的 通过测量颈动脉的内膜-中层厚度(IMT)和阻力指数(RI)来探讨颈动脉粥样硬化和糖尿病的关系。 方法 选择糖尿病患者作为观察组(50人)进行常规体检及血生化检查,排除了高血压、高血脂、脑梗等疾病后,应用血管超声技术测量颈动脉的IMT及阻力指数。并选用非相关疾病患者(50人)作为对照组。 结果 在两组患者的年龄、性别、体重指数、收缩压、舒张压、总胆固醇、甘油三酯、高密度脂蛋白、低高密度脂蛋白等指标均无明显差异的情况下(p>0.05),糖尿病组的颈动脉的IMT及RI值均显著高于对照组(p<0.05)。 结论 通过颈动脉超声检查颈动脉的内膜-中层厚度和阻力指数显示糖尿病患者颈动脉粥样硬化的高发生率。     

Abnormal cerebrovascular reactivity in patients with asymptomatic atherosclerosis of the carotid arteries

The study included 53 patients (males at the age of 44-78 years) with ischemic heart disease and arterial hypertension with asymptomatic unilateral atherosclerotic affection of carotid arteries (CA). Ultrasonic investigation registered 30-80% stenosis of carotid arteries in the absence of neurological deficit. Cerebrovascular reactivity was assessed by means of the hypercapnic hypoxic test (HHT) including breathing via additional "dead space" for 3 min. Initial and peak linear velocity of the blood flow in the middle cerebral artery was measured with ultrasonic transcranial dopplerography. By HHT results, three types of cerebral vascular reactions in patients with combined atherosclerosis of coronary and carotid arteries were identified: subnormal dilatation on the side of stenosed internal carotid artery, increased dilatation and paradoxical vasoconstriction on the affected side. Cerebrovascular reactivity and the type of atherosclerotic plaques did not collerate.