Multidetector-row CT angiography in the study of atherosclerotic carotid arteries

Pathologies of the carotid arteries, and in particular atherosclerosis, are now an important medical problem. Stroke is the third leading cause of severe disability in the Western World leading to millions of deaths every year. Extracranial carotid atherosclerotic disease is the major risk factor for stroke. In years, with the advent of multidetector-row CT (MDCT) scanners and the use of specific angiographic protocols (MDCTA), CT imaging of the carotid arteries has become increasingly effective. In addition, the volume data obtained can be further rendered to generate high-quality two-dimensional and three-dimensional images. The purpose of this study was to review the atherosclerotic carotid arteries, their complications and how MDCTA depicts them, underlining the benefits and pitfalls of this diagnostic technique.     

冠状动脉造影和颈动脉超声对动脉粥样硬化的比较研究

目的：了解颈动脉粥样硬化和冠状动脉粥样之间的关系,为寻求简单、无创伤和常规检查动脉粥样硬化程度,评估冠心病发病可能。方法：选择一组年龄62～89岁老年研究样本,分别进行冠状动脉造影和颈动脉彩超,分别记录冠状动脉狭窄程度、狭窄支数,彩超记录动脉壁厚、内膜厚、内径狭窄程度、硬化斑块数、收缩期和舒张期血流峰值速度等参数,比较冠状动脉和颈动脉硬化参数间关系。结果：颈动脉动脉粥样硬化出现病变程度随着冠状动脉病变血管支数和斑块数增加而增加。另外,这些变化还出现在内膜厚度／腔内径比值,收缩期峰值血流,舒张期峰值血流等血流变等方面,两者病变呈一定程度相关性。结论：冠状动脉粥样硬化与颈动脉粥样硬化具有高度的相关性,颈动脉超声粥样斑块的检测作为一无创、简单易行手段可作为预测冠心病发病的重要预测信号。     

Detection of internal carotid artery stenosis: comparison of MR angiography, color Doppler sonography, and arteriography.

Findings of two-dimensional time-of-flight magnetic resonance (MR) angiography projection angiograms were prospectively compared with those of color Doppler sonography by using angiography as a standard in 23 consecutive patients (42 carotid bifurcations) to evaluate their utility in determining the presence of carotid artery stenosis. MR angiography helped detect 50% or greater lumen diameter stenosis (sensitivity, 0.96; specificity, 0.64). Color Doppler sonography with 1.25 m/sec peak systolic velocity as a threshold had a sensitivity of 0.96 and a specificity of 0.71. Statistical analysis showed a correlation between percentage of lumen diameter narrowing and the length of the zone of signal intensity loss with MR angiography (r = .69; P less than .0001). A stronger relationship was obtained between angiographic narrowing and peak systolic velocity derived from color Doppler sonography (r = .80; P less than .0001). Two-dimensional time-of-flight MR angiography displayed as projection angiograms and combined with carotid artery and combined with carotid artery sonography is a useful approach for helping detect and potentially grade the severity of stenoses of the carotid artery.     

CT angiography in the assessment of carotid artery atherosclerosis

Objective: The aim of the study was to evaluate the ability of CT angiography (CTA) to detect atherosclerosis of the carotid arteries in comparison with 3D time-of-flight MR angiography (3D TOF MRA), using contrast angiography and intravascular ultrasound (IVUS) as a reference.Material and Methods: Contrast angiography and CTA were performed in 31 patients (mean age 65 years, range 45-79). The image quality was evaluated, atherosclerotic lesions were registered, and diameter stenosis degree was visually estimated from axial source images of CTA and 3D TOF MRA (21 patients), and results of interpretations were compared. The comparison of quantitative measurements was performed using IVUS as a reference.Results: Contrast angiography detected 51 lesions (mean diameter stenosis 50%, range 10-100%), and CTA detected all same lesions. CTA provided better image quality and consistency of image interpretation than 3D TOF MRA. IVUS verified 29 atherosclerotic lesions with a mean diameter stenosis of 35%, (range 4-40%). CTA yielded a sensitivity of 96% to 100% (≤10% or ≤20% diameter stenosis regarded as normal) for the detection of lesions with reference to IVUS.Conclusion: CTA seems feasible and accurate for the detection of atherosclerosis in carotid arteries.     

增强磁共振成像与颈动脉造影在颈动脉狭窄诊断中的应用价值

目的：探讨增强磁共振成像与颈动脉造影在颈动脉狭窄诊断中的应用价值。方法对72例经颈动脉彩超检查疑有颈动脉狭窄的患者采用三维对比增强磁共振血管造影和数字减影血管造影进行检查。结果3D CE-M RA检出颈动脉狭窄112处,DSA检出108处,经统计学分析发现3D CE-M RA检出率（36．84％）与DSA检出率（35．53％）比较无明显差异（x2＝0．11,P ＞0．05）。本文以DSA为诊断颈动脉狭窄的金标准,对3D CEMRA诊断的112处颈动脉狭窄进行敏感性和特异性评估,评估结果显示敏感性为0．81（0．69～0．89）特异性为0．99（0．98～1．00）,ROC曲线下面积为0.95。结论3D CE-M RA诊断颈动脉敏感性和特异性均较高,对颈部动脉狭窄闭塞性病变的显示具有独特的优势。     

Stent impact on the geometry of the carotid bifurcation and the course of the internal carotid artery

A measurement system is proposed to evaluate reconstructive effects of carotid stents on the geometry of the carotid bifurcation and the course of the internal carotid artery. To describe deviations of the stenotic internal carotid artery (ICA) from the extended axis of the common carotid artery (CCA) the CCA-ICA angle is measured between the CCA midaxis and the midaxis of the stenotic ICA segment. Maximal extensions of ICA tortuosities perpendicular to the course of the CCA axis are defined as ICA offset. The measurements were applied to DSA images of 224 carotid stenoses to evaluate variation and correlation between the two parameters. Comparative pre- and post-stent evaluation was performed in two series of 55 and 31 carotid stenoses treated with Wallstents and in a historic control group of 35 stenoses treated with Strecker stents. Straight course of the ICA was associated with low angle and low offset values, whereas tortuous course of the ICA showed larger angle and offset. A moderate linear correlation between the two parameters was found. Corresponding to a straightening of the stented segment, Wallstents reduced mean angle and offset values significantly. In five cases of the second series of Wallstents, transferrals of curves above the distal stent end associated with kinks were observed, and offset remained constant or increased. Strecker stent implantation caused no significant changes of bifurcational geometry. The proposed parameters corresponded to visual aspects of ICA tortuosity and detected reconstructive effects of self-expanding Wallstents on the ICA course. The measurement system may provide a basis for geometric evaluation of different stent types or implantation concepts with the aim: to optimize anatomic recanalization results in tortuous high angle-high offset bifurcations.     

Peripatetic carotid artery simulating a carotid dissection on catheter angiography and CT angiography: a case report

Retropharyngeal carotid arteries are a common clinically relevant anatomic variant. “Peripatetic” carotid arteries refer to change in position to and from a retropharyngeal location, and are a newly described finding. Knowledge of this phenomenon is important to avoid potential procedural complications as well as misdiagnosis. We present a unique case of a peripatetic carotid artery simulating a carotid artery dissection during a catheter angiogram and subsequent CT angiogram. To our knowledge, this has never been described in the medical literature.     

巴马小型猪颈动脉粥样硬化性狭窄模型建立技术探讨

【摘要】 目的 探讨血管内介入法构建猪颈动脉动脉粥样硬化（AS）狭窄模型的方法和要点,并观察天冬酰胺内肽酶（AEP）表达水平。方法 按照随机数字表法将24头巴马小型猪分成实验组（12头）和对照组（12头）。术前实验组给予高脂饲料喂养,8周末全身麻醉下经股动脉行颈动脉内大球囊过度扩张,构建颈动脉狭窄模型;对照组仅给予基础饲料喂养。入组时和造模后第1、8、16、24周末分别行体质量称量和血脂水平检验,采用彩色多普勒超声和DSA监测评估颈动脉狭窄形成。术后24周处死实验猪,收集狭窄处标本,苏木素伊红（HE）染色观察病理学改变,免疫组化染色分析AEP表达水平。总结血管内介入法构建猪颈动脉AS狭窄模型的技术操作要点。结果 高脂喂养后,实验组体质量和血脂水平均较对照组升高（均P＜0.05）。术后24周,彩色多普勒超声和DSA证实实验组12头猪颈动脉AS狭窄模型构建成功,狭窄率为（33.21±13.17）%;与对照组相比,实验组狭窄组织病理学检查证实有明显的AS斑块形成。实验组颈动脉狭窄组织中AEP高表达,阳性细胞比率为（79.41±11.34）%,吸光度值为0.73±0.11,阳性评分12分;对照组中AEP低表达,阳性细胞比率为（27.13±17.34）%,吸光度值为0.41±0.14,阳性评分为6分,两组比较差异有统计学意义（均P＜0.01）。结论 24周高脂饲养和大球囊过度扩张诱导颈动脉内膜损伤,可确切可靠地建立巴马小型猪颈动脉AS狭窄模型。AEP在巴马小型猪颈动脉AS狭窄病变中高表达,可能参与了AS斑块的形成。     

EEG controlled occlusion of the internal carotid artery during angiography

Summary It became evident in two patients during cerebral angiography that ligation of an internal carotid artery would probably be necessary in the course of a subsequent neurosurgical operation. A balloon catheter was inserted and the internal carotid artery was occluded. A continous EEG recording was made with a Fourier transformed frequency analysis before and during the occlusion; the motor functions of the corresponding side of the body were observed simultaneously on the conscious patient. EEG alterations indicative of cerebral ischemia were not demonstrated in either patient during an occlusion period of 7 min. Unilateral neurosurgical ligation of the common carotid artery and the internal carotid artery was performed on one patient. As predicted no neurological deficit occured.     

Time-resolved three-dimensional contrast-enhanced MR angiography of the carotid artery]

Contrast-enhanced MR angiography (ceMRA) allows practical carotid arteriography without venous enhancement. However, it requires some intricate preparation such as a test bolus of the contrast agent or determination of the tracking volume even in the automatic triggering Smartprep system. The purpose of this study was to obtain carotid ceMRA without any preparation by means of a repeated multiple ultrashort three-dimensional MRA sequence (e3d56), i.e., time-resolved MRA (trMRA). Twenty-three patients underwent sagittal trMRA using a 1.0-Tesla superconducting unit. Multiple projection angiograms are acquired in three contiguous phases with a time resolution of 6 seconds per slab, including 10 partitions, after a bolus injection of 10 ml of Gd-DTPA followed by 20 ml of saline at 2 ml/sec. In all patients, the signal from the arteries could be separated from that of the veins in at least one phase. Carotid trMRA with 6-sec temporal resolution is a reliable technique for selective arteriography, avoiding the necessity of timing the contrast agent bolus.     

多层螺旋CT血管造影术诊断动脉粥样硬化性肾动脉狭窄的价值

目的 探讨多层螺旋CT血管造影(MSCTA)诊断动脉粥样硬化性肾动脉狭窄(ARAS)的必要性和可靠性.方法 选取82例曾做过数字减影血管造影(DSA)的ARAS患者行肾动脉MSCTA,将所获得的图像数据进行多平面重建、最大密度投影法重建、容积重建和表面阴影遮盖法重建,将结果与DSA进行对比分析.结果 ①MSCTA发现狭...     

3D TRICKS MRA对颈动脉粥样硬化狭窄的诊断价值

目的：探讨3D TRICKS MRA对颈动脉粥样硬化狭窄的诊断价值。方法：对43例临床疑诊颈动脉粥样硬化狭窄的患者行2D TOF MRA和3D TRICKS MRA检查,其中31例同期行DSA检查,以颈总动脉法（CC法）计算狭窄率。结果：颈动脉闭塞2支,重度狭窄10支,中度狭窄31支,轻度狭窄25支,正常18支。2D TOF MRA、3D TRICKS MRA与DSA对照,显示狭窄部位均与DSA所示相符。2D TOF MRA高估狭窄程度6支,3D TRICKS MRA高估狭窄程度1支。以DSA为标准,2D TOF MRA诊断颈动脉狭窄的敏感度、特异度、诊断符合率分别为91.6%,85.7%,90.3%（K=0.737）;3D TRICKS MRA诊断颈动脉狭窄的敏感度、特异度、诊断符合率分别为97.9%,100%,98.4%（K=0.955）。两种方法对诊断颈动脉狭窄的敏感度、特异度和诊断符合率差异均具有统计学意义（P〈0.05）。结论：3D TRICKS MRA与DSA对评估颈动脉粥样硬化狭窄具有极好的一致性（K=0.955）,明显优于2D TOF MRA（K=0.737,P〈0.05）,是对颈动脉粥样硬化狭窄筛查、术前评估、术后随访的最佳检查方法,能基本替代DSA检查。     

动脉粥样硬化性肾动脉狭窄与高血压相关性的MDCTA研究

目的利用MDCTA评价动脉粥样硬化性肾动脉狭窄与高血压之间的相关性。方法对42例动脉粥样硬化性肾动脉狭窄的高血压患者的多层螺旋CT血管成像进行重建、分析,判断肾动脉狭窄的程度,对观察者间的一致性进行评价,并将肾动脉狭窄评分与血压进行相关性分析。结果 MDCTA评价肾动脉狭窄的观察者间一致性较好,kappa值为0.71。42例患者中,22例为双侧肾动脉狭窄,20例为单侧肾动脉狭窄,共64支狭窄肾动脉,其中钙化性斑块32支,混合性斑块21支,非钙化性斑块11支,狭窄部位均为肾动脉近段。肾动脉狭窄评分与收缩压及舒张压呈正的直线相关,相关系数r为0.834,决定系数R2为0.695。结论 MDCTA是评价动脉粥样硬化性肾动脉狭窄的最佳无创性检查手段之一,粥样硬化性肾动脉狭窄的程度与高血压之间存在正性直线相关。     

Scan-Rescan reproducibility of carotid bifurcation geometry from routine contrast-enhanced MR angiography

Purpose

To demonstrate the feasibility of rapid and reliable geometric characterization of normal carotid bifurcation geometry from routine 3D contrast‐enhanced magnetic resonance (MR) angiograms.

Materials and Methods

Repeat scans of 61 participants, acquired as part of the Atherosclerosis Risk in Communities (ARIC) Carotid MRI substudy, were digitally segmented using automated 3D level set methods, relying on an operator only to select the branch endpoints and thresholds for the 3D lumen surface initialization. Geometric factors characterizing the 3D lumen geometry were then extracted automatically.

Results

Of 122 scans, 117 could be segmented within 5 minutes each, with 40% being of sufficiently high quality to require less than 2 minutes each. Irrespective of scan quality, geometric factors were found to be highly reproducible, with intraclass correlation coefficients (ICCs) typically above 0.9. The reconstructed lumen surfaces were reproducible to <0.3 mm on average, comparable to previous MRI‐based reproducibility studies. Owing to the automated nature of the analysis, operator reliability was near‐perfect (ICC >0.99), with lumen surface differences <0.1 mm.

Conclusion

The 3D geometry of the carotid bifurcation can be characterized rapidly and with a high degree of consistency, even for suboptimal image qualities. This bodes well for large‐scale retrospective or prospective studies aimed at teasing out the influence of local vs. systemic risk factors for early atherosclerosis. J. Magn. Reson. Imaging 2011;33:482–489. © 2011 Wiley‐Liss, Inc.