颈动脉MR高分辨成像:变性斑块的MR表现及其病理基础

目的 应用3.0 T MR高分辨成像在体显示颈动脉粥样斑块,探讨斑块变性的MRI表现及其病理基础.资料与方法 经彩超证实的症状性颈动脉狭窄37例,均行管壁高分辨MRI.包括三维时间飞跃法(3DTOF)、双翻转脉冲(DIR)T1WI、T2WI及质子密度加权成像(PDWI).其中,22例检查前1周内行CT血管造影,9例检查后1周内行颈动脉内膜剥脱术,5例1周内置颈动脉支架.根据颈动脉内膜剥脱术的部位,将获得的病理标本与MR图像逐层对照,分析斑块钙化、出血和脂质坏死池的MRI表现,探讨斑块变性的MRI表现及其病理基础.结果 37例共发现52支颈动脉分叉处斑块,斑块钙化21支(40.4%),无钙化斑块31支(59.6%).31支软斑块中,纤维成分为主斑块8支(15.6%),有明显脂质核心斑块23支(44.2%);伴斑块出血5支(9.6%),脂质坏死核心3支(5.8%),"纤维帽"撕裂(溃疡或"纤维帽"撕裂)3支(5.8%).相对于胸锁乳突肌,脂质坏死池在TOF、T1WI、PDWI、T2WI均呈显著高信号,钙化在各序列均呈低信号.斑块内出血的信号与出血的时间有关,新鲜出血各序列表现为点、结节或片状高信号,亚急性出血或者陈旧性出血的信号与出血时间的长短有关.结论 斑块变性包括脂核坏死、出血和钙化,脂质坏死池和出血提示斑块处于高风险状态,而钙化提示斑块稳定.斑块不同变性的信号不同,MR高分辨成像可显示这些变性,为斑块风险预防和治疗提供参考.     

颈动脉粥样斑块3T MR高分辨成像和MRA诊断

目的:应用3.0T MR高分辨管壁成像和MR血管造影在体显示颈动脉粥样斑块,探讨MR对颈动脉斑块的诊断价值。方法:经彩超检查证实的症状性颈动脉狭窄37例,所有病例行管腔MRA和管壁高分辨MR检查,MR检查序列包括3DTOF、DIR T1WI、T2WI、PDWI和MRA。其中,17例检查前1周内行CT血管造影检查,9例患者检查后1周内行颈动脉内膜剥脱术。根据颈动脉内膜剥脱术手术部位,将获得的病理标本与MR图像逐层对照,研究斑块脂质成分、纤维成分和纤维帽、斑块钙化、出血和脂质坏死池等MR表现,探讨斑块变性的MR表现及其病理基础。结果:37个病例共发现52条颈动脉分叉处斑块,其中,管腔轻度狭窄24条(46.1%),中度狭窄19条(36.5%),重度狭窄7条(13.5%),闭塞2条(3.9%)。斑块钙化21条(40.4%)、无钙化斑块31条(59.6%);31条软斑块中纤维成分为主斑块8条(15.6%),有明显脂质核心斑块23条(44.2%);其中,伴斑块出血5条(10%)、脂质坏死核心3条(6%),纤维帽撕裂(溃疡或纤维帽撕裂)3条(6%)。相对于胸锁乳突肌,脂质坏死池在TOF、T1WI、PDWI、T2WI均呈显著高信号,钙化在各序列均呈低信号。斑块内出血的信号与出血的时间有关,新鲜出血各序列表现为点、结节或片状高信号,亚急性出血或者陈旧出血的信号与出血时间长短有关。结论:颈动脉MRA和管壁高分辨成像是评估颈动脉斑块风险性的有效手段,无创性MRA可以显示颈动脉斑块的狭窄程度;管壁高分辨成像可以直接显示斑块纤维帽、斑块内结构和成分,预测斑块脱落的风险性。     

CT与MRI对颈动脉狭窄和粥样硬化斑块特征的评估价值

目的 探讨CT和MRI评估颈动脉狭窄和粥样硬化斑块性质的效果。方法 选取我院确诊为缺血性脑血管病的患者108例,采用CT和MRI检查,观察两种检查方式对颈动脉狭窄和粥样硬化斑块性质的评估价值。结果 两种影像学检查方法图像质量对比差异无统计学意义(P> 0.05)。两种检查方式在血管狭窄程度和斑块内钙化的检查中差异无统计学意义(P> 0.05);但MRI对斑块内出血的检出率明显高于CT(P <0.05)。结论 CT和MRI均能有效判断颈动脉病变和颈动脉的狭窄程度,但MRI对粥样硬化斑块的评估更全面检查。     

3.0T MRI对颈动脉粥样硬化不稳定性斑块的研究

目的:通过3.0T MRI评价颈动脉粥样硬化不稳定性斑块的成分及其分布的特点.方法:对37例经超声诊断颈动脉中重度狭窄患者进行3.0T MRI检查,分析斑块高分辨MR图像,根据斑块表面纤维帽的完整性判定斑块不稳定情况,定量测量管腔、管壁、斑块成分的面积比例、纵向长度,并计算总管腔面积、血管负荷指数、偏心指数.结果:3.0T MRI共发现15例不稳定性斑块(不稳定性斑块组).不稳定性斑块组和稳定性斑块组在血管纵向分布上大面积脂质核心长度分别为7mm、0mm;血管负荷指数中位数分别为0.69、0.58;斑块内出血的发生率分别为82.1％和41.7％;差异均有统计学意义(P＜0.05).不稳定性斑块组偏心分布更明显,狭窄范围更长.平均管腔面积为23.87 mm2、30.16mm2,偏心指数分别为3.65、2.79,差异均有统学意义(P＜0.05).结论:不稳定性斑块在纵向及血管横断面分布上具有明显的特点,3.0T MRI可评价颈动脉粥样硬化不稳定性斑块的成分及分布特点.     

颈动脉斑块脂质和纤维成份高分辨MRI表现及其病理基础

目的：应用3.0T MR高分辨成像（HRMR）在体显示颈动脉粥样斑块,探讨斑块脂质成分和纤维成分的HRMR表现及其病理基础。方法：经彩超检查证实的症状性颈动脉狭窄37例,均行管壁高分辨MRI检查,检查序列包括3D TOF、DIR T1WI、T2WI及PDWI。其中22例检查前1周内行CTA检查,9例检查后1周内行颈动脉内膜剥脱术,5例接受颈动脉支架置入术。根据颈动脉内膜剥脱术斑块所在的颈动脉部位,将获得的病理标本与MRI图像逐层对照,研究斑块纤维成分和纤维帽、脂质成分和脂质坏死池的MRI表现,探讨MRI表现的病理基础。结果：37例共发现52支颈动脉存在斑块,斑块钙化21支（40.4%）、无钙化斑块31支（59.6%）;31支软斑块中,纤维成分为主者8支（15.6%）,有明显脂质核心斑块23支（44.2%）;其中,伴斑块出血5支（10%）、脂质坏死核心3支（6%）,纤维帽撕裂（溃疡或纤维帽撕裂）3支（6%）。相对于胸锁乳突肌,斑块脂质成分在TOF图像上呈等信号,T1WI呈等信号或稍高信号,PDWI多呈等信号或略高信号、少数呈低信号,T2WI上呈等信号或低信号;脂质坏死池在TOF、T1WI、PDWI和T2WI上均呈高信号;纤维帽和纤维成分的信号相仿,在TOF图像上呈等信号或低信号,T1WI上呈高信号或略高信号,PDWI呈稍高或等信号,T2WI上呈稍高信号。硬斑块纤维帽厚度（1.1±0.4）mm,软斑块纤维帽厚度（0.7±0.3）mm。硬斑块和软斑块的纤维帽厚度差异有统计学意义（P〈0.001）。结论：多序列高分辨MRI可以显示斑块脂质成分、纤维成分和纤维帽,并对斑块脂质和纤维帽进行初步的定量,为在体分析斑块的结构提供评价指标,为斑块风险性评价提供参考。     

能谱CT重建模式与64层CT重建模式对于颈动脉粥样硬化斑块评估能力的对比分析

目的 对比分析能谱CT与64层CT后处理技术对颈动脉粥样硬化斑块病变评估能力的差异.方法 回顾性分析38例46个颈动脉斑块的能谱CT检查资料.颈动脉CT采用能谱扫描模式,重建方式分为能谱模式重建及非能谱模式重建(传统64层CT重建).通过能谱曲线、碘基图、脂基图分析颈动脉增强扫描期斑块的成分,并与病理或大体标本对照;观察颈动脉分叉处管腔的狭窄程度和斑块的病变特征,包括纤维帽的状况、斑块内出血和脂质.计算Kappa值分析能谱CT和64层CT对血管狭窄程度判断结果的一致性;应用独立样本t检验、确切概率法检验检测两种方法对颈动脉斑块成分及溃疡斑块的检出差异.结果 能谱CT重建模式显示血管狭窄程度为(63.3±3.1)％,64层CT重建模式显示为(61.6±3.8)％,二者具有很好的一致性(Kappa值为0.993,P＜0.01).颈动脉能谱CT重建模式显示12个颈动脉斑块有纤维帽破溃,64层CT重建模式显示11个颈动脉斑块有纤维帽破溃,两者间差异无统计学意义(P＞0.05).颈动脉能谱CT通过能谱曲线、碘基、脂基图分析显示11个颈动脉斑块内有出血,而64层CT重建模式未能显示,两者间差异有统计学意义(P＜0.05);斑块内出血碘浓度为(6.365±1.937) mg/cm3,无斑块内 出 血的斑块碘浓度为(1.573±0.776) mg/cm3,两者比较差异有统计学意义(t=16.39,P＜0.05).能谱CT重建模式显示9个颈动脉斑块内富含脂质成分,64层CT重建模式仅显示2个,两者间差异有统计学意义(P＜0.05);能谱CT显示28个颈动脉斑块内有钙化,64层CT显示27例,两者间差异无统计学意义(P＞0.05).结论 能谱CT重建模式在显示斑块内出血、脂肪成分较64层CT重建模式更具优势.     

高分辨力MRI对颈动脉粥样硬化斑块稳定性评估的价值

目的 :探讨高分辨力MRI对动脉粥样硬化斑块稳定性评估的价值。方法 :选择28例经颈动脉超声诊断为颈动脉粥样硬化斑块的患者行斑块高分辨力MRI检查,观察颈动脉粥样硬化斑块的成分。结果:28例17个不稳定性斑块和15个稳定性斑块中,高分辨力MRI显示钙化、脂质核心、纤维帽、斑块内出血及纤维斑块差异均有统计学意义(均P0.05)。结论:高分辨力MRI对斑块成分及稳定性判定有重要价值。     

磁共振黑血iMSDE序列在颈动脉狭窄诊断中的初步临床应用体会

目的通过与数字减影血管造影(DSA)比较,评价MR黑血运动致敏驱动平衡改良技术(improved motionsensitized driven equilibrium,iMSDE)序列在诊断颈动脉狭窄中的临床价值。方法对32例患者的39支粥样硬化狭窄性颈动脉进行DSA及黑血iMSDE成像,比较两者在评估狭窄处最小管腔直径、狭窄处斑块累及长度、斑块破溃和判断最大狭窄部位的差异。结果黑血iMSDE成像与DSA相比:在判断颈动脉最大狭窄部位有较好的一致性(Kappa值=0.894);狭窄处最小管腔直径无显著性差异[(3.3±0.9)mm vs(3.2±0.8)mm,P=0.098];黑血iMSDE成像所示狭窄处斑块累及长度明显大于DSA[(21.9±5.6)mm vs(15.3±3.4)mm,P<0.001];黑血iMS-DE成像与DSA显示斑块破溃一致性较好。结论磁共振黑血iMSDE成像能清晰显示颅外段颈动脉管壁结构和粥样斑块的形态,并为临床提供较可靠和有价值的信息。     

颈动脉增强对评价颈动脉斑块稳定性的作用

目的:通过分析颈动脉粥样硬化(AS)血管壁的强化特征,评价血管壁强化程度与斑块稳定性之间的关系.方法:148例临床疑为颈部血管狭窄的患者中61例行CTA、87例行CE-MRA检查,分析斑块的类型并测量邻近血管壁的强化程度以及管腔狭窄程度,评价管壁强化特征与斑块稳定性之间的关系.CTA组部分患者与DSA对照.结果:CTA组:狭窄血管74支,轻度狭窄34支,中度狭窄24支,重度狭窄19支,3支完全闭塞;软斑块32块,硬斑块25块,溃疡斑6块,软斑块处血管壁强化明显高于硬斑块,部分患者与DSA比较,二种检查方法对血管狭窄的显示无显著性差异.CE-MRA组:狭窄血管79支,轻度狭窄28支,中度狭窄33支,重度狭窄13支,5支完全闭塞;软斑块28块,硬斑块49块,血栓2块,软斑块处血管壁强化明显高于硬斑块.结论:CTA和CE-MRA在评价颈动脉粥样硬化斑块的稳定性方面各有优势,能够为临床预测缺血性脑卒中提供非常可靠准确的信息.     

64层螺旋CT血管成像对颈动脉分叉处病变的临床应用

目的探讨64层螺旋CT血管成像（CTA）在诊断颈内动脉狭窄和粥样硬化斑块中的价值，并与当前血管成像的金标准DSA进行比较。方法对40例病人（80个颈动脉）进行了CTA和DSA检查，两项检查时间间隔不超过1周，并将CTA与DSA结果进行对照，计算出两者之间的敏感度和特异度。结果CTA对轻度（狭窄程度：0-29％）颈动脉狭窄和颈动脉闭塞显示得非常好，其敏感度和特异度均接近100％。在明确经DSA测量狭窄程度〉50％的狭窄时，CTA敏感度、特异度分别为89％、91％。CTA在鉴别狭窄程度为50％-69％或70％～99％时的特异度高，而敏感度较低．分别为65％和73％。CTA同时可以检出DSA不能发现的所有类型的斑块。结论64层CTA在显示颈内动脉狭窄方面与DSA有很好的一致性，同时可发现与颈动脉狭窄相关的溃疡，而DSA只能显示狭窄。     

颈动脉粥样硬化斑块高分辨磁共振成像扫描方法

目的:规范颈动脉粥样硬化斑块高分辨磁共振成像方法,优化扫描序列及参数.材料和方法:采用颈动脉专用线圈,选用2D-TOF、3D-TOF、T1WI、T2WI、PDWI等脉冲序列,对156例不同程度脑缺血症状患者行颈动脉斑块多序列多方位扫描.结果:156例受检者除2名不能配合未完成扫描外,其余均顺利完成.T1WI、T2WI、PDWI和3D-TOF的序列组合能准确显示血管壁、血流、斑块大小、形态及斑块内成分.其中62例显示明确斑块形成(最大狭窄＞50%),34例判定为稳定斑块;28例判定为不稳定斑块,其中手术病理证实22例,病理提示斑块纤维帽不完整、部分合并出血钙化及巨大脂质池.结论:采用颈动脉专用表面线圈,选用合适的扫描序列及参数所得到的图像能有效显示斑块,为临床治疗方案的选择及术后随访提供依据.     

Intraplaque Hemorrhage and the Plaque Surface in Carotid Atherosclerosis: The Plaque At RISK Study (PARISK)

BACKGROUND AND PURPOSE:An important characteristic of vulnerable plaque, intraplaque hemorrhage, may predict plaque rupture. Plaque rupture can be visible on noninvasive imaging as a disruption of the plaque surface. We investigated the association between intraplaque hemorrhage and disruption of the plaque surface.MATERIALS AND METHODS:We selected the first 100 patients of the Plaque At RISK study, an ongoing prospective noninvasive plaque imaging study in patients with mild-to-moderate atherosclerotic lesions in the carotid artery. In carotid artery plaques, disruption of the plaque surface (defined as ulcerated plaques and/or fissured fibrous cap) and intraplaque hemorrhage were assessed by using MDCTA and 3T MR imaging, respectively. We used a χ² test and multivariable logistic regression to assess the association between intraplaque hemorrhage and disrupted plaque surface.RESULTS:One hundred forty-nine carotid arteries in 78 patients could be used for the current analyses. Intraplaque hemorrhage and plaque ulcerations were more prevalent in symptomatic compared with contralateral vessels (hemorrhage, 38% versus 11%; P < .001; and ulcerations, 27% versus 7%; P = .001). Fissured fibrous cap was more prevalent in symptomatic compared with contralateral vessels (13% versus 4%; P = .06). After adjustment for age, sex, diabetes mellitus, and degree of stenosis, intraplaque hemorrhage was associated with disrupted plaque surface (OR, 3.13; 95% CI, 1.25–7.84) in all vessels.CONCLUSIONS:Intraplaque hemorrhage is associated with disruption of the plaque surface in patients with a carotid artery stenosis of <70%. Serial studies are needed to investigate whether intraplaque hemorrhage indeed increases the risk of plaque rupture and subsequent ischemic stroke during follow-up.

The need to identify patients with mild-to-moderate carotid artery stenosis and an increased stroke risk who might benefit from surgical treatment has shifted research interest from assessment of the degree of carotid stenosis to assessment of vulnerable plaque characteristics.¹ Vulnerable plaques are atherosclerotic plaques more prone to rupture and are associated with a higher risk for thromboembolism and ischemic stroke.^2,3 Intraplaque hemorrhage is an important characteristic of the vulnerable plaque.⁴ Prevalence of intraplaque hemorrhage has been shown to be higher in symptomatic than in asymptomatic lesions.⁵ Moreover, the presence of intraplaque hemorrhage in carotid artery disease is associated with an increased risk of cerebral ischemic events.^6–8The pathophysiologic mechanism leading to intraplaque hemorrhage is a topic of debate. However, a common viewpoint is that small leaky neovessels in the atherosclerotic plaques are a likely source of intraplaque hemorrhage.^5,9,10 The presence of intraplaque hemorrhage is thought to initiate several biologic processes like phagocytosis and local inflammation, leading to the release of proteolytic enzymes, deposition of free cholesterol and subsequently plaque growth, plaque destabilization, and possible plaque rupture.^5,9–12 Plaque rupture can be visible on imaging as a disruption of the atherosclerotic plaque surface (plaque ulceration and/or a fissured fibrous cap).^13,14 A previous study reported that plaque ulceration on CTA was useful for the prediction of intraplaque hemorrhage on MR imaging in a broad group of symptomatic patients referred for carotid artery imaging.¹⁵ Ulcerated plaques themselves are independently associated with an increased risk of ipsilateral ischemic events as well.^16,17The aim of the current study was to investigate the association between intraplaque hemorrhage, as assessed on MR imaging, and disruption of the plaque surface, assessed on MDCTA, in symptomatic patients with a carotid artery stenosis of <70%.     

In vivo detection of hemorrhage in human atherosclerotic plaques with magnetic resonance imaging

PURPOSE: To investigate the performance of high-resolution T1-weighted (T1w) turbo field echo (TFE) magnetic resonance imaging (MRI) for the identification of the high-risk component intraplaque hemorrhage, which is described in the literature as a troublesome component to detect. MATERIALS AND METHODS: An MRI scan was performed preoperatively on 11 patients who underwent carotid endarterectomy because of symptomatic carotid disease with a stenosis larger than 70%. A commonly used double inversion recovery (DIR) T1w turbo spin echo (TSE) served as the T1w control for the T1w TFE pulse sequence. The MR images were matched slice by slice with histology, and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the MR images were calculated. Additionally, two readers, who were blinded for the histological results, independently assessed the MR slices concerning the presence of intraplaque hemorrhage. RESULTS: More than 80% of the histological proven intraplaque hemorrhage could be detected using the TFE sequence with a high interobserver agreement (Kappa = 0.73). The TFE sequence proved to be superior to the TSE sequence concerning SNR and CNR, but also in the qualitative detection of intraplaque hemorrhage. The false positive TFE results contained fibrous tissue and were all located outside the main plaque area. CONCLUSION: The present study shows that in vivo high-resolution T1w TFE MRI can identify the high-risk component intraplaque hemorrhage with a high detection rate in patients with symptomatic carotid disease. Larger clinical trials are warranted to investigate whether this technique can identify patients at risk for an ischemic attack.     

双源CT双能量去骨技术在颈动脉狭窄病变中的应用价值

目的:探讨双源CT双能量去骨技术在颈动脉钙化性狭窄病变中的应用价值。方法:回顾性分析18例颈动脉钙化性狭窄患者的病例资料,根据北美症状性颈动脉内膜切除试验(NASCET)标准评价血管的狭窄程度,分析颈动脉双能量去骨技术去除钙化斑块后的图像与DSA图像在量化分析颈动脉狭窄程度上的相关性。以DSA图像为对照,评价双能量去骨技术诊断钙化性颈动脉狭窄的敏感性、特异性、准确性、阳性和阴性预测值。结果:64段有明显致密钙化斑块的颈动脉血管,双能量去骨技术检出54个血管节段狭窄,DSA检出50个血管节段狭窄,两者对于颈动脉钙化性狭窄病变的检出差异无统计学意义(P>0.05),两者对于狭窄程度的分级相关性好(R2=0.913)。以DSA为对照,双能量去骨技术检出颈动脉狭窄的敏感度为98.0%,特异度为100.0%,符合率为90.6%,阳性预测值为90.7%,阴性预测值为90.0%。结论:采用双能量去骨技术去除钙化斑块可以很好地评价颈动脉钙化性狭窄病变。     

Imaging of the Fibrous Cap in Atherosclerotic Carotid Plaque

In the last two decades, a substantial number of articles have been published to provide diagnostic solutions for patients with carotid atherosclerotic disease. These articles have resulted in a shift of opinion regarding the identification of stroke risk in patients with carotid atherosclerotic disease. In the recent past, the degree of carotid artery stenosis was the sole determinant for performing carotid intervention (carotid endarterectomy or carotid stenting) in these patients. We now know that the degree of stenosis is only one marker for future cerebrovascular events. If one wants to determine the risk of these events more accurately, other parameters must be taken into account; among these parameters are plaque composition, presence and state of the fibrous cap (FC), intraplaque haemorrhage, plaque ulceration, and plaque location. In particular, the FC is an important structure for the stability of the plaque, and its rupture is highly associated with a recent history of transient ischaemic attack or stroke. The subject of this review is imaging of the FC.     

磁共振EC TRICKS序列与DSA在主动脉弓分支血管病变中的对比研究

目的：探讨椭圆中心时间决定对比剂动态成像法（EC TRICKS）与数字减影血管造影（DSA）在主动脉弓分支血管病变诊断中的应用价值。方法：搜集本院83例患者资料,分别应用GE Signa HD1.5T磁共振仪及GE Advantx LC DSA机器,对全部患者主动脉弓分支血管行EC TRICKS及DSA成像,EC TRICKS后处理利用多平面重组及最大信号强度投影技术对原始图像进行血管重现。结果：EC TRICKS扫描,83例中有82例主动脉弓分支血管显示良好符合诊断要求,1例检查失败,DSA全部病例显影良好。依是否存在狭窄为标准,82例EC TRICKS诊断结果与DSA保持良好一致性。其中右侧锁骨下动脉狭窄5例,左侧锁骨下动脉狭窄14例;左、右侧椎动脉狭窄各17例;颈总动脉狭窄左侧31例,右侧24例;颈内动脉狭窄左侧32例,右侧20例;无名动脉狭窄11例。结论：ECTRICKS能无创性的清晰显示主动脉弓分支血管走行及管腔狭窄程度,为临床医生提供准确的诊断定位及治疗依据。     

颈动脉粥样斑块的多排螺旋CT血管造影及流行病学分布特征

目的:分析150例颈动脉粥样斑块病例,探讨其MDCTA表现及其临床流行病学分布特征。方法:经大范围MDCTA检查的颈动脉粥样斑块150例,所有病例均行彩色多谱勒超声检查,29例行DSA检查。应用横断面图像寻找斑块,根据病变的特点行2D、3D后处理,探讨其分布、形态、狭窄程度、钙化、不规则及溃疡等规律。根据斑块的钙化和纤维帽的完整性作为斑块风险性的评价指标,狭窄程度的判断采用NASCET标准。结果:150例病例中共发现317处斑块,其中,颈动脉起始部斑块37例,颈总动脉28例,颈动脉分叉部173例,颈内动脉44例,颈外动脉35例。轻、中、重狭窄及闭塞的发病率分别为30.95%、49.41%、16.96%及3.87%。分叉段斑块钙化率为64.7%,分叉段以外区域为23.9%。分叉段斑块不规则和溃疡的发病率为16.8%,分叉段以外为15.95%。分叉段狭窄程度以轻中度狭窄为主;分叉段以外以中重度狭窄比例高。结论:颈动脉不同区域粥样斑块的分布、形态、钙化和狭窄程度差异存在显著性意义,高风险斑块发病率相似,局限于分叉段的颈动脉检查可能漏诊高风险斑块。     

大范围颈动脉MDCTA与DSA的对照研究

目的 通过比较MDCTA与DSA对颈动脉病变的诊断差异以期评价MDCTA的临床应用价值。材料与方法 （1）搜集经颈动脉DSA和MDCTA检查的临床病例19例。（2）随机选择实验动物猪10头,通过导丝损伤和外科手术建立猪颈动脉血管腔内、腔外狭窄模型,行DSA和MDCTA造影对照。根据国外采用的分类方法并结合血管外科手术与否的判断标准,以50％为界将狭窄程度分成两组,分别评价MDCTA诊断价值。数据分析采用诊断实验评价。结果 DSA检查正常13例中,MDCTA正常12例,1例误诊为轻度狭窄。狭窄血管56处,MDCTA漏诊3处。MDCTA对颈动脉狭窄程度的判断与DSA有很好的相关性,敏感性为94．6％,特异性为92．3％,准确性94．2％,阳性预测值为98．2％,阴性预测值为80．0％。其中,狭窄在50％以下者37处,CTA漏诊3处,敏感性为91．9％;狭窄超过50％者19处,MDCTA无漏诊,敏感性为100％。MDCTA显示病灶不规则内表面4例,斑块溃疡3例,均经病理标本证实,而DSA显示不规则2例,溃疡1例。结论 颈动脉MDCTA可以取代诊断用途的DSA。在显示血管狭窄的形态、斑块表面不规则、斑块溃疡以及重度狭窄后血管等方面,大范围颈动脉MDCTA更有优势。     

Characterisation of carotid atherosclerotic plaque: comparison between magnetic resonance imaging and histology

PURPOSE: The aim of this study was to identify and characterise by magnetic resonance imaging (MRI) carotid plaque constituents such as lipid-rich necrotic core, intraplaque haemorrhage and calcification in patients treated with carotid endarterectomy (CEA) using histological evaluation as the reference standard. MATERIALS AND METHODS: Nineteen patients (13 men and six women) scheduled for CEA between March and August 2004 were imaged on a 1.5-T scanner (Magnetom Symphony, Siemens, Erlangen, Germany). The protocol included four types of sequences [T1, T2, proton density (PD) and three-dimensional time of flight (3D-TOF)]. Images were reviewed for integrity of the fibrous cap, presence of lipid-rich necrotic core, intraplaque haemorrhage and calcification. Signal intensity was assessed relative to the adjacent sternocleidomastoid muscle. Four cross-sections for each lesion were compared with the corresponding histological specimens and independently reviewed by two radiologists and one pathologist. RESULTS: MRI detected lipid-rich necrotic core with a sensitivity and specificity of 91.6% and 95.0%, respectively, whereas it defined intraplaque haemorrhage alone with a sensitivity and specificity of 91.6% and 100%, respectively. Calcification was recognised with a sensitivity and specificity of 80% and 93.7%, respectively. CONCLUSIONS: MRI is able to identify signs of carotid plaque instability with a high sensitivity and specificity. Therefore, it may be useful in evaluating and guiding the treatment of haemodynamically nonsignificant stenoses with a potential embolic risk and, in the future, to assess coronary plaque.