MRI of carotid atherosclerosis

Summary  MRI of carotid atherosclerosis provides a unique method to characterize plaque morphology and tissue composition, as well as, to a certain extent, plaque inflammation. Because of its noninvasiveness, it has many current and potential applications: the fact that it is the only technique that can examine the fibrous cap status in vivo makes it a powerful tool to identify high-risk plaques. With quantitative measurement achievable on a series of plaque compositional and morphologic features, this technique is also well suited for studying atherosclerosis progression and regression. This technique can also be combined with other imaging modalities such as ultrasound and nuclear medicine to create a comprehensive evaluation of carotid atherosclerosis from tissue compliance and composition to inflammation.     

颈动脉分叉区解剖类型与动脉粥样硬化相关性的CTA评价

目的:利用多层螺旋CT血管成像(MSCTA)评价颈动脉分叉区(CCAB)解剖类型及其与动脉粥样硬化关系.方法:回顾性分析2005年～2008年在我院行颈动脉CT血管造影的78例受检者的156侧图像.CT机采用日本东芝Aquilion 16层螺旋CT机,扫描范围自主动脉弓上缘至颅底水平;对比剂使用碘海醇90～100ml.流速3ml/s;45例采用SURESTAR技术跟踪扫描,兴趣区设在主动脉弓,阈值120～160HU;33例采用经验值,扫描延迟时间设定为20s;图像后处理技术主要采用VR、MIP等.结果:CCAB形态中1型14侧,占8.97%;2型80侧,占51.2%;3型62侧,占39.7%.CCAB夹角大多数在21°～40°之间.78例受检者中,发现有斑块的血管43例、51处,其中:颈总动脉分叉处15处,颈总动脉11处,颈内动脉窦部17处,颈外动脉8处.43例斑块患者中累及47侧血管,其中:1型3侧,占6.38%;2型20侧.占42.55%;3型24侧.占51.06%.斑块在不同分叉角度的发生率:≤20°3侧.占6.38%;21°～50°18侧.占38.29%;≥51°26侧;占55.31%.结论:应用MSCTA可以准确评价CCAB的解剖,为进一步分析其与动脉粥样硬化的发生、发展提供了一种简便易行的技术.     

MRI对颈动脉粥样硬化患者的临床应用(附46例报告)

为探讨MRI对颈动脉粥样硬化患者诊断中的应用价值[1～4],本文收集46例颈动脉粥样硬化发生脑梗死的患者临床资料,分析其影像学表现,提高诊断水平。1材料与方法1.1临床资料收集2009年10月～2010年3月我院收治的46例经超声检查确诊为颈动脉粥样硬化的患者临床资料,根据临床表     

超声检查对高血压颈动脉粥样硬化的评价及血流动力学分析

 目的 探讨高频超声探头观察高血压患者颈动脉内-中膜厚度及斑块形成的诊断价值.方法 使用高频超声对68例高血压患者,观察其颈动脉内-中膜厚度及有无斑块形成的情况,并检查48例健康体检为对照组.根据颈动脉超声检测有无粥样硬化将研究对象分为研究阳性组,研究阴性组,对照阳性组,对照阴性组.结果 研究阳性组共42例,占研究组61.8%,研究阴性组26例,占研究组38.2%,对照组阳性组13例,占对照组27.1%,对照阴性组37例,占对照组72.9%.研究组颈动脉粥样硬化检出率明显高于对照组(P<0.01).结论 本组研究表明高血压患者颈动脉内径明显增宽,血流速度明显减低,导致最大剪切力明显低于正常对照组,内中膜厚度增加与颈动脉粥样硬块密切相关,高血压患者血流动力学的改变对动脉硬化的发生及进展起着重要作用.     

MRI动态增强扫描在评估颈动脉斑块稳定性中的应用

目的:采用MRI动态增强扫描(DCE-MRI)测算厚壁斑块、薄壁斑块与破裂斑块容积传输常数(Ktrans),评估新生血管,为易损斑块的早期诊断提供依据。方法:怀疑有动脉粥样硬化斑块的41例患者均行MRI平扫及动态增强扫描。根据MRI平扫图像对斑块进行分类,其中厚壁斑块15个,薄壁斑块9个,破裂斑块11个。根据DCE-MRI图像后处理获得各型斑块容积传输常数(Ktrans)。结果:厚壁斑块与薄壁、破裂斑块Ktrans值比较,差异均有统计学意义(均P0.05),薄壁斑块与破裂斑块Ktrans值之间,差异无统计学意义(P0.05)。结论:Ktrans值反映了不同类型斑块新生血管及炎性浸润的不同,可作为早期评估斑块稳定性的一个指标。     

Efficient flow suppressed MRI improves interscan reproducibility of carotid atherosclerosis plaque burden measurements

Purpose:

To determine if better flow suppression can meaningfully improve the reproducibility of measurements associated with carotid atherosclerotic disease, particularly for lumen and wall areas.

Materials and Methods:

Eighteen subjects with carotid artery stenosis identified by duplex ultrasound (11 with 16%–49% stenosis; 7 with 50%–79% stenosis) underwent two carotid magnetic resonance imaging (MRI) examinations on a 3T scanner with a 4‐channel phased array coil. High‐resolution intermediate‐weighted TSE (TR/TE = 4000/8.5 msec, 0.55 mm in‐plane resolution, 2 mm slice thickness, 16 slices, 3‐minute scan time) with two different flow‐suppression techniques (multislice double inversion recovery [mDIR] and motion‐sensitized driven‐equilibrium [MSDE]) were obtained separately. For each subject, bilateral arteries were reviewed. One radiologist blinded to timepoints, flow suppression techniques, and clinical information measured the arterial lumen area, wall area, and total vessel wall area.

Results:

Compared to mDIR, the MSDE technique had a smaller interscan standard deviation (SD) in lumen (SD: 3.6 vs. 5.2 mm², P = 0.02), wall area measurements (SD: 4.5 vs. 6.4 mm², P = 0.02), and a trend towards smaller SD in total vessel area measurement (SD: 4.4 vs. 4.9 mm², P = 0.07).

Conclusion:

The results from this study demonstrate that vessel wall imaging could quantify atherosclerotic plaque measurements more reliably with an improved blood suppression technique. This relationship between flow‐suppression efficiency and reproducibility of plaque measurements is important, as more reliable area measurements will be useful in clinical diagnosis and in serial MRI studies that monitor carotid atherosclerotic lesion progression and regression. J. Magn. Reson. Imaging 2010;32:452–458. © 2010 Wiley‐Liss, Inc.     

Contrast‐enhanced MRI of carotid atherosclerosis: Dependence on contrast agent

Purpose

To investigate the dependence of contrast‐enhanced magnetic resonance imaging (MRI) of carotid artery atherosclerotic plaque on the use of gadobenate dimeglumine versus gadodiamide.

Materials and Methods

Fifteen subjects with carotid atherosclerotic plaque were imaged with 0.1 mmol/kg of each agent. For arteries with interpretable images, the areas of the lumen, wall, and necrotic core and overlying fibrous cap (when present) were measured, as were the percent enhancement and contrast‐to‐noise ratio (CNR). A kinetic model was applied to dynamic imaging results to determine the fractional plasma volume, v_p, and contrast agent transfer constant, K^trans.

Results

For 12 subjects with interpretable images, the agent used did not significantly impact any area measurements or the presence or absence of necrotic core (P > 0.1 for all). However, the percent enhancement was greater for the fibrous cap (72% vs. 54%; P < 0.05) necrotic core (51% vs. 42%; P = 0.12), and lumen (42% vs. 63%; P < 0.05) when using gadobenate dimeglumine, although no apparent difference in CNR was found. Additionally, K^trans was lower when using gadobenate dimeglumine (0.0846 min^?1 vs. 0.101 min^?1; P < 0.01), although v_p showed no difference (9.5% vs. 10.1%; P = 0.39).

Conclusion

Plaque morphology measurements are similar with either contrast agent, but quantitative enhancement characteristics, such as percent enhancement and K^trans, differ. J. Magn. Reson. Imaging 2009;30:35–40. © 2009 Wiley‐Liss, Inc.

     

颈动脉粥样硬化与股动脉粥样硬化的比较

目的:比较颈动脉粥样硬化与股动脉粥样硬化的异同点。方法:将205名受试者分为正常组(n=85)和冠心病组(n=120),进行颈动脉和股动脉超声检查,并对年龄、体重指数、血压、吸烟史、血脂、血糖、颈动脉内膜中层厚度(IMT)、股动脉IMT及冠心病家族史、男性性别进行单因素分析和Logistic分析。结果:①股动脉IMT及血管弹性指标较颈动脉呈增高趋势;②冠心病组颈动脉斑块发生率显著高于股动脉斑块发生率;③多因素分析表明年龄、血糖、家族史、颈动脉IMT是冠心病的危险因素。结论:股动脉与颈动脉在血管IMT、血管僵硬度、动脉斑块发生率存在差异;颈动脉IMT是冠心病的高危因素。     

脑胶质瘤微血管通透性灌注MRI研究进展

肿瘤微血管高通透性是脑胶质瘤的典型病理特征,与肿瘤恶性程度、分子分型及患者预后密切相关。由于采用外源性钆对比剂,传统灌注MRI检查可导致部分患者出现严重过敏反应和体内钆沉积,其安全性受到质疑。非对比剂灌注MRI不仅能够无创、定量、动态地评价肿瘤微血管血液动力学特征,而且安全性高,患者接受度好,现已逐渐应用于科研及临床工作中。本文着重于非对比剂MRI技术,综述灌注MRI评价胶质瘤微血管通透性的应用及研究进展。     

MRI of atherosclerosis

The emergence of high-resolution, rapid imaging methods has enabled MRI to noninvasively image the fine internal structure of atherosclerotic artery walls. This capability has, in turn, captured the interest of clinicians, who see it as an opportunity to assess disease severity based on the characteristics of atherosclerotic lesions themselves, rather than only their effects on the vessel lumen. MRI of atherosclerosis thus has the potential to be used in medical treatment decisions or to assess the effects of experimental treatment options. Given this potential, a number of research groups have been investigating MRI of atherosclerosis in an effort to establish the ability of MRI to determine atherosclerotic plaque burden, detect plaque composition, and ultimately identify vulnerable plaque before it leads to a clinical event. In this review, the current state of the art is summarized for the three primary vessel targets: the carotid artery, the aorta, and the coronary arteries.     

降压药物对高血压颈动脉粥样硬化干预的超声评价

目的通过超声检查评价波依定对高血压颈动脉粥样硬化的干预,探讨颈动脉超声检查在降压药物疗效评估中的作用。方法检查80例高血压患者服药前后收缩压、舒张压、平均IMT、最大IMT、动脉粥样硬化等级评分指标水平变化。结果经治疗后收缩压、舒张压、平均IMT、最大IMT、等级评分指标水平较治疗前均明显下调,与治疗前比较有显著性差异（P〈0.05或P〈0.01）。结论颈动脉超声可以检测动脉粥样硬化病理变化的改善,可用于临床药物评价。     

血流灰阶显像技术评估血浆同型半胱氨酸水平与动脉粥样硬化的相关性研究

目的探讨血浆同型半胱氨酸（Hey）水平与动脉粥样硬化（AS）的关系。方法选择2010年2月--2012年2月住院治疗的脑梗死患者100例（观察组）及健康体检者100例（对照组）,行颈动脉超声检查,利用血流灰阶显像（BFI）技术及彩色多普勒显像（CDFI）技术,观察颈动脉内一中膜厚度（IMT）、斑块的有无。同时抽外周静脉血查Hcy水平,并进行比较分析。结果观察组血浆Hey水平较对照组高,AS程度重,二者比较差异有统计学意义（P〈0．01）。运用BFI技术检测斑块阳性率较CDFI技术高,二者差异有统计学意义（P〈0．05）。结论血浆Hcy水平与AS呈正相关,检测血浆Hey水平有助于As的早期诊断和干预。BFI技术是评估As的有效手段。     

A rabbit model of atherosclerosis at carotid artery: MRI visualization and histopathological characterization

To induce a rabbit model of atherosclerosis at carotid artery, to visualize the lesion evolution with magnetic resonance imaging (MRI), and to characterize the lesion types by histopathology. Atherosclerosis at the right common carotid artery (RCCA) was induced in 23 rabbits by high-lipid diet following balloon catheter injury to the endothelium. The rabbits were examined in vivo with a 1.5-T MRI and randomly divided into three groups of 6 weeks (n=6), 12 weeks (n=8) and 15 weeks (n=9) for postmortem histopathology. The lesions on both MRI and histology were categorized according to the American Heart Association (AHA) classifications of atherosclerosis. Type I and type II of atherosclerotic changes were detected at week 6, i.e., nearly normal signal intensity (SI) of the injured RCCA wall without stenosis on MRI, but with subendothelial inflammatory infiltration and proliferation of smooth muscle cells on histopathology. At week 12, 75.0% and 62.5% of type III changes were encountered on MRI and histopathology respectively with thicker injured RCCA wall of increased SI on T(1)-weighted and proton density (PD)-weighted MRI and microscopically a higher degree of plaque formation. At week 15, carotid atherosclerosis became more advanced, i.e., type IV and type V in 55.6% and 22.2% of the lesions with MRI and 55.6% and 33.3% of the lesions with histopathology, respectively. Statistical analysis revealed a significant agreement (p<0.05) between the MRI and histological findings for lesion classification (r=0.96). A rabbit model of carotid artery atherosclerosis has been successfully induced and noninvasively visualized. The atherosclerotic plaque formation evolved from type I to type V with time, which could be monitored with 1.5-T MRI and confirmed with histomorphology. This experimental setting can be applied in preclinical research on atherosclerosis.     

兔颈动脉粥样硬化模型:MRI表现及组织病理学特征

制作兔颈动脉粥样硬化模型,利用MRI显示病变的进展,组织病理学显示病变的类型。利用气囊式导管损伤颈总动脉内皮后予以高脂饮食制作23例兔右侧颈总动脉     

灰阶血流显像技术对阿托伐他汀治疗颈动脉粥样硬化的疗效评估

目的运用灰阶血流显像(BFI)技术评估阿托伐他汀治疗颈动脉粥样硬化的疗效。方法选择2011年1月至2013年12月在我院诊治的120例动脉粥样硬化患者作为研究对象。按随机数字表法将其分为治疗组(60例)和对照组(60例),两组患者均给予常规治疗。治疗组每晚服用阿托伐他汀20 mg,对照组每晚服用相同剂量安慰剂(面粉)。两组治疗周期均为6个月。分别在治疗前及治疗后用超声的彩色多普勒血流显像(CDFI)技术和BFI技术对患者颈动脉进行检查,观察内中膜厚度(IMT)及斑块检出率。结果治疗后超声检查,治疗组IMT及斑块检出率较对照组减低,两组间比较,差异均有显著统计学意义(P<0.01);运用BFI技术后斑块检出率高于CDFI技术,两组间比较,差异有统计学意义(P<0.05)。结论阿托伐他汀对颈动脉粥样硬化的治疗效果确切,BFI技术为动脉粥样硬化的诊断提供了一种新的技术。     

The complementary roles of dynamic contrast-enhanced MRI and 18F-fluorodeoxyglucose PET/CT for imaging of carotid atherosclerosis

Purpose

Inflammation and neovascularization in vulnerable atherosclerotic plaques are key features for severe clinical events. Dynamic contrast-enhanced (DCE) MRI and FDG PET are two noninvasive imaging techniques capable of quantifying plaque neovascularization and inflammatory infiltrate, respectively. However, their mutual role in defining plaque vulnerability and their possible overlap has not been thoroughly investigated. We studied the relationship between DCE-MRI and ¹⁸F-FDG PET data from the carotid arteries of 40 subjects with coronary heart disease (CHD) or CHD risk equivalent, as a substudy of the dal-PLAQUE trial (NCT00655473).

Methods

The dal-PLAQUE trial was a multicenter study that evaluated dalcetrapib, a cholesteryl ester transfer protein modulator. Subjects underwent anatomical MRI, DCE-MRI and ¹⁸F-FDG PET. Only baseline imaging and biomarker data (before randomization) from dal-PLAQUE were used as part of this substudy. Our primary goal was to evaluate the relationship between DCE-MRI and ¹⁸F-FDG PET data. As secondary endpoints, we evaluated the relationship between (a) PET data and whole-vessel anatomical MRI data, and (b) DCE-MRI and matching anatomical MRI data. All correlations were estimated using a mixed linear model.

Results

We found a significant inverse relationship between several perfusion indices by DCE-MRI and ¹⁸F-FDG uptake by PET. Regarding our secondary endpoints, there was a significant relationship between plaque burden measured by anatomical MRI with several perfusion indices by DCE-MRI and ¹⁸F-FDG uptake by PET. No relationship was found between plaque composition by anatomical MRI and DCE-MRI or ¹⁸F-FDG PET metrics.

Conclusion

In this study we observed a significant, weak inverse relationship between inflammation measured as ¹⁸F-FDG uptake by PET and plaque perfusion by DCE-MRI. Our findings suggest that there may be a complex relationship between plaque inflammation and microvascularization during the different stages of plaque development. ¹⁸F-FDG PET and DCE-MRI may have complementary roles in future clinical practice in identifying subjects at high risk of cardiovascular events.     

颈动脉内膜剥脱术治疗颈动脉粥样硬化狭窄的临床研究

目的探讨颈动脉内膜剥脱术（carotid endarterectomy,CEA）的适应证及围手术期处理。方法回顾性总结2001年2月—2011年2月在我科治疗的98例因颈动脉硬化狭窄（狭窄＞50%）而行CEA治疗的患者资料;其中,有症状77例（786%）,无症状21例（214%）。结果术后除2例（20%）死亡、3例（30%）发生一过性偏瘫和7例（71%）出现脑高灌注综合征外,其他患者疗效良好,未出现短暂脑缺血（transient ischemic attack,TIA）表现。术后随访1~10年,平均56年;随访76例,13例（17.1%）再狭窄＞70%,9例（118%）再发TIA症状,4例（53%）出现脑梗死。结论对于临床检查发现一侧或双侧颈动脉狭窄＞50%,特别是有TIA发作史的患者,可以考虑行CEA;双侧颈动脉狭窄者应分期手术治疗;做好围手术期处理,有助于减少手术并发症发生。     

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.     

多模态MRI评估宫颈癌缺氧及缺氧治疗的研究进展

缺氧是宫颈癌的不利因素之一,在评估肿瘤快速生长、转移、放化疗抵抗方面具有重要意义。多种病理机制可导致宫颈癌缺氧。近年来由于MRI具有无创性及可重复测量的优势,在反映缺氧机制、表征缺氧状态及评估缺氧治疗的疗效和预后方面取得了一定进展。就多模态MRI应用于宫颈癌缺氧及缺氧治疗方面的研究进展予以综述。