3.0T MRI 3D Space序列对颅脑动脉斑块出血的诊断应用

目的探讨磁共振可变翻转角的三维快速自旋回波(3D-sampling perfection with application optimized contrast using different flip angle evolutions, 3D-SPACE)序列检测大脑中动脉斑块内出血(intraplaque hemorrhage, IPH)的成像情况及其诊断价值。方法选取我院就诊的脑动脉粥样硬化的患者100例,所有患者均接受常规MRI检查、3D序列亮血时飞法MR血管成像(time-of-flight magnetic resonance angiography, TOFMRA),同时接受3D-SPACE序列检查。根据常规序列(T₁WI、T₂WI、3D TOF、T₁WI-CE)图像综合评估IPH,并根据患者的临床、影像学结果对所有患者进行评估,将患者分为有症状组和无症状组。对比两组患者3D-SPACE序列评估斑块信号的高低情况,同时对比3D-SPACE及常规MRI各序列对IPH的评估效果。结果有症状组72例患者中通过3D...     

运用3.0T磁共振探讨颈动脉与大脑中动脉斑块负荷的关系

目的应用3.0T磁共振研究急性脑缺血患者颈动脉和患侧大脑中动脉的斑块负荷,探究两者之间的关系。方法 50例经临床和MRI证实为急性前循环缺血的患者在发病1周内行颈动脉和患侧大脑中动脉磁共振多序列检查,测得各血管的管腔面积(LA)、管壁面积(WA)、血管总面积(TVA),并计算出管壁标准化指数(NWI=WA/TVA)。结果①同一患者两侧的颈动脉NWI之间差异无统计学意义(P>0.05);②大脑中动脉M1段的NWI(0.62±0.07)比同侧颈动脉的NWI(0.36±0.06)显著增高(P<0.01);③同侧颈动脉与大脑中动脉M1段的NWI间存在显著的相关性(左侧r=0.89,P<0.001;右侧r=0.79,P<0.001)。结论动脉粥样硬化是一种系统性病变,可以同时累及多个血管床,而急性脑缺血患者以大脑中动脉斑块负荷增加更为显著。     

大脑中动脉粥样硬化斑块HRMRI与缺血性卒中的相关性分析

目的分析大脑中动脉粥样硬化斑块在高分辨率磁共振成像(HRMRI)中的影像学特征与急性/亚急性缺血性卒中的相关性。方法用3.0 T磁共振对105例大脑中动脉粥样硬化的患者进行检查,采用优化的三维可变翻转角度快速自旋回波(SPACE)T₁WI序列,观察大脑中动脉狭窄处斑块的HRMRI影像学特征。评价内容包括最小管腔面积、斑块负荷及斑块强化率等。将患者分为卒中组(发生急性/亚急性缺血性卒中)和非卒中组(未发生急性/亚急性缺血性卒中),使用卡方检验或独立样本t检验对两组患者的斑块特征进行统计学分析。结果 105例患者中58例发生急性/亚急性缺血性卒中。卒中组40例患者见斑块内高信号;43例见管腔狭窄(管腔狭窄率<50%)。其中斑块内高信号(χ²=33.31,P<0.001)、最小管腔面积(t=2.755,P=0.007)和斑块强化率(t=8.573,P<0.001)与急性/亚急性缺血性卒中的发生具有相关性。两组之间管腔狭窄(管腔狭窄率<50%)及斑块负荷比较无统计学差异(P>0.05)。结论大脑中动脉粥样硬化斑块HRMR...     

高分辨力MR成像检查大脑中动脉粥样硬化斑块的研究进展

颅内动脉粥样硬化在亚洲是缺血性卒中的主要病因,其在我国的脑卒中和短暂性脑缺血发作中也有较高发生率。高分辨力MR成像作为目前唯一可以在体进行的血管壁成像的无创技术,临床应用越来越广泛,尤其是对大脑中动脉的研究。高分辨力MR成像能评估动脉管腔的狭窄程度、斑块分布、斑块信号特点、管壁重构方式等,为临床治疗提供更多的有用信息。现就近年来高分辨力MR成像检查颅内大脑中动脉粥样硬化斑块的研究进展进行综述。     

3.0 T HRMRI对脑动脉粥样硬化显像优势的初步研究

目的 应用3.0T高分辨率磁共振成像(high-resolution MRI,HRMRI)研究MRA未见明确狭窄的急性有症状腔隙性脑梗死患者脑动脉粥样硬化情况.方法 搜集2013年9月至2014年4月在南方医院住院的47例患者,所有患者均为MRI常规扫描发现急性腔隙性梗死灶、3D-TOF法MRA未见明确狭窄后,进一步行HRMRI检查.31例HRMRI提示中度以上狭窄后进一步行DSA检查.结果 大脑中动脉责任斑块位置以上壁和下壁多见,基底动脉以前壁和后壁居多,28例责任斑块突入或覆盖穿支动脉开口;HRMRI最狭窄处狭窄率与DSA狭窄程度有显著相关性(P＜0.001),HRMRI显示的血管重构与DSA狭窄程度之间有相关性(P＜0.05),MRA局部管腔信号是否减低与DSA血管狭窄有相关性(P＜0.05).结论 3.0 T HRMRI在评价脑动脉管壁结构有明显的优势,与3D-TOF MRA互补,可以较好地评价脑动脉粥样硬化情况,指导临床早期进行正确的干预和治疗.     

应用高分辨率MRI探讨大脑中动脉斑块与脑卒中类型的关系

目的 探讨大脑中动脉斑块与脑卒中类型的关系.方法 选取76例脑卒中患者,行常规头部MRI及高分辨率磁共振成像(HR-MRI)扫描.测量病灶侧大脑中动脉斑块厚度,评估斑块分布位置及斑块强化程度,并行统计学分析.结果 76例患者中急性脑梗死组32例,非急性脑梗死组25例,短暂性脑缺血发作(TIA)组19例.急性脑梗死组斑块...     

MRI 3D SNAP序列对大脑中动脉斑块内出血的研究

目的 分析三维非增强血管造影和斑块内出血成像(SNAP)序列上大脑中动脉(MCA)粥样硬化斑块的图像特征,并探讨其与临床症状的关系.资料与方法 回顾性分析76例动脉粥样硬化MCA狭窄患者的三维非增强血管造影、T1加权三维容积各向同性快速自旋回波序列和SNAP图像.根据患者有无急性脑血管事件发生分为症状组44例与无症状组...     

大脑中动脉形态与斑块分布及卒中的HR-MRI研究

目的 分析大脑中动脉(MCA)几何特征与动脉粥样硬化斑块分布和卒中的关系.方法 纳入症状性MCA斑块患者,根据有无梗死分为两组;并进一步根据斑块是否累及内侧壁分组,利用三维磁共振血管成像(3D-MRA)及重组最大密度投影(MIP)识别MCA曲线类型及方向,于高分辨率磁共振成像(HR-MRI)上确定斑块分布及其他斑块特征...     

基于活体MRI的3D流-固耦合模型分析对症状性大脑中动脉粥样硬化斑块的研究

【摘要】 目的：以症状性大脑中动脉（MCA）斑块的活体高分辨率磁共振成像（HR-MRI）数据为基础,建立3D完全耦合的流-固耦合（FSI）模型,探索不同组分MCA斑块的生物力学特征。方法：研究对象为拟行介入手术治疗的12例症状性单侧MCA局限性动脉粥样硬化狭窄的患者。首先,术前对MCA管壁行HR-MRI作为力学建模的形态学依据;其次,利用相位对比MRI技术和DSA引导下的测压微导管分别采集MCA狭窄前端的血流参数和血压数据作为载荷条件,并对目标血管的3D几何结构进行网格生成等前处理,导入有限元程序软件ADINA（ADINA R&D,Inc,USA）进行FSI求解;最后,从3D-FSI结果中提取3个力学指标值：最大主应力（MPS）、最大主伸长比（STRETCH-P1）和最大剪应力（FMSS）,分析比较不同狭窄程度和不同斑块成分的各项力学指标的差异。结果：按照狭窄率分组比较发现,轻中度狭窄组的MPS、STRETCH-P1和FMSS与重度狭窄组之间的差异均无统计学意义（P=0.9323、0.3872和0.1271）。分析不同斑块成分发现,含"脂质核心"斑块的层面中MPS稍高于含“纤维成分”斑块（P=0.0744）,STRETCH-P1明显高于“纤维成分”斑块（P=0.0169）,FMSS显著低于“纤维成分”斑块（P=0.0021）。结论：症状性MCA粥样硬化病变中,“脂质核心”斑块的主应力和主伸长比均不同程度地高于“纤维化”斑块,提示富含脂质坏死核心斑块的机械负荷较大、可能有相对较高的破裂风险。     

颈动脉粥样硬化的高分辨力MRI研究

目的:评价高分辨力MRI在显示和评价颈动脉粥样硬化斑块方面的价值。方法:采用3in表面线圈,DIRT1WI、FSET2WI和3DTOF序列对19例患者及3例志愿者进行颈动脉高分辨力MRI成像,评价有无硬化斑块并对其初步分型。结果:MRI清晰显示15例31处颈动脉粥样硬化改变,包括颈总动脉4处,颈动脉分叉17处,颈内动脉9处及颈外动脉1处。硬化斑块在DIRT1WI、FSET2WI表现为管壁不规则增厚,根据其信号改变参照AHA分类分为Ⅲ型12个、Ⅳ～Ⅴ型11个,Ⅵ型2个,Ⅶ型6个。在显示血管壁改变方面DIRT1WI优于其它序列。结论:高分辨力MRI能清晰显示颈动脉粥样硬化改变,根据其信号改变能判断其组成成分及其性质,为临床选择治疗方案及预后提供帮助。     

运用3.0T MR高分辨多序列技术对颈动脉斑块分型的研究

目的:探讨3.0T MRI高分辨多序列成像对颈动脉斑块的定位和分型能力.方法:31例经超声筛选的颈动脉斑块患者,在3.0T磁共振仪上,采用相控阵颈部线圈和心电门控,行3D-TOF、T1WI、T2WI和PDWI横断面扫描,在颈总动脉、分叉部及颈内动脉3个部位,对斑块进行初步定性和分型.结果:25例共150个血管断面中,Ⅰ～Ⅱ型占34%,Ⅲ型占44.7%,Ⅳ～Ⅴ型占14%,Ⅵ型占3.3%,Ⅶ型占4.0%;Ⅶ型的钙化斑块均被CT所证实.不同类型斑块在颈动脉各部位的分布上差异无显著性意义(P=0.112).Ⅵ型病例近期均有同侧大脑半球颈动脉供血区缺血事件发生.结论:在3.0T MR上应用高分辨多序列技术能清晰显示颈动脉血管壁的细微结构和斑块的形态特征,对进展期斑块具有准确定位和初步分型能力,可作为一项无创性评价颈动脉粥样斑块的理想方法.     

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.     

磁共振测定颈动脉斑块负荷与脑梗死缺血灶体积的关系

目的 应用3.0T磁共振测量急性脑缺血患者头颅缺血灶体积和颈动脉斑块负荷,探究两者之间的关系.方法 94例急性脑缺血患者在发病1周内行头颅和颈动脉磁共振多序列检查(头颅T1WI、T2WI、T2 FLAIR、DWI;颈动脉亮血3DTOF,黑血T1WI、T2WI及MPRAGE),测得脑内缺血灶的体积和颈动脉的管腔面积(LA)、血管总面积(TVA),并计算出管壁面积(WA)和管壁标准化指数(NWI).结果 (1)94例病例中,90例的图像符合研究要求;(2)两侧颈内动脉供血区缺血灶体积间差异均无统计学意义(P＞0.05);(3)两侧颈动脉的平均血管总面积(TVA)、管腔面积(LA)、管壁面积(WA)和管壁标准化指数(NWI)间的差异无统计学意义(P＞0.05);(4)缺血侧颈动脉的管壁标准化指数(NWI)较非缺血侧大,差异有统计学意义(P＜0.05) ;(5)颈动脉斑块负荷与同侧大脑缺血灶体积间存在明显的正相关(P＜0.01).结论 颈动脉粥样硬化与脑梗死的发生密切相关,3.0T磁共振黑血技术能定量测量颈动脉斑块负荷,从而对预测脑缺血事件的发生以及监测病情的进展、评价预后提供帮助.     

3.0 T磁共振3D CUBE T2 WI抑脂序列对肛瘘的诊断价值

目的 探讨3.0T常规MRI T2 WI抑脂序列联合三维超长回波链采集FSE(3D CUBE) T2 WI抑脂序列对肛瘘患者的临床诊断价值.方法 回顾性分析33例经手术证实的肛瘘患者术前常规MRI T2WI抑脂序列及3DCUBE T2 WI抑脂序列资料.比较两种技术评价肛瘘分型、瘘管支数、内口总数、外口数目、肛周脓肿和瘘管整体的优势,并与手术结果相对照.结果 手术发现33例肛瘘中,经括约肌瘘14例,括约肌间瘘10例,括约肌外瘘8例,括约肌上瘘1例.瘘管支数52个,内口45个,外口48个,肛周脓肿30个.常规MRI T2WI抑脂序列与常规MRI T2WI抑脂序列联合3D CBUE T2WI抑脂序列肛瘘的分型准确率分别为78.8％ (26/33)和87.9％ (29/33),差别无统计学意义(JP＞0.05);瘘管支数显示率分别为71.2％(37/52)和90.4％ (47/52),内口总数显示率分别为71.1％ (32/45)和91.1％ (41/45),差异具有统计学意义(P＜0.05).两种技术显示外口数目和肛周脓肿与手术结果一致.结论 常规MRI T2WI抑脂序列联合3D CUBE T2WI抑脂序列能准确显示瘘管支数、内口总数和瘘管整体,优于常规MRI T2 WI抑脂序列,为临床术前提供更详尽的影像解剖信息.     

肝右后下静脉3.0T磁共振VIBE序列影像解剖学研究

目的 评价磁共振三维容积式内插值法屏气检查(VIBE)序列对肝右后下静脉(IRHV)解剖特征的显示能力.方法 对85例受检者肝静脉行MRI增强扫描获得原始图像,用多平面重组和最大密度投影进行重组,观察IRHV影像学特征.结果 85例受检者的图像中有50例出现IRHV,显示率为58.8％.所显示的IRHV为1～5条,平均(1.62 ±0.88)条.直径为0.22 ～ 0.95cm,平均(0.41±0.18)cm.IRHV与肝右静脉(RHV)距离为2.10～7.50 cm,平均(4.23±1.31)cm.IRHV与下腔静脉夹角41°～107°,平均(74.6±12.7)°.IRHV管径与RHV管径呈负相关(r=-0.778,P=0.000).结论 MRI增强扫描可以评价IRHV的解剖学特征.     

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.     

Quantitative Intracranial Atherosclerotic Plaque Characterization at 7T MRI: An Ex Vivo Study with Histologic Validation

BACKGROUND AND PURPOSE:In recent years, several high-resolution vessel wall MR imaging techniques have emerged for the characterization of intracranial atherosclerotic vessel wall lesions in vivo. However, a thorough validation of MR imaging results of intracranial plaques with histopathology is still lacking. The aim of this study was to characterize atherosclerotic plaque components in a quantitative manner by obtaining the MR signal characteristics (T1, T2, T2*, and proton density) at 7T in ex vivo circle of Willis specimens and using histopathology for validation.MATERIALS AND METHODS:A multiparametric ultra-high-resolution quantitative MR imaging protocol was performed at 7T to identify the MR signal characteristics of different intracranial atherosclerotic plaque components, and using histopathology for validation. In total, 38 advanced plaques were matched between MR imaging and histology, and ROI analysis was performed on the identified tissue components.RESULTS:Mean T1, T2, and T2* relaxation times and proton density values were significantly different between different tissue components. The quantitative T1 map showed the most differences among individual tissue components of intracranial plaques with significant differences in T1 values between lipid accumulation (T1 = 838 ± 167 ms), fibrous tissue (T1 = 583 ± 161 ms), fibrous cap (T1 = 481 ± 98 ms), calcifications (T1 = 314 ± 39 ms), and the intracranial arterial vessel wall (T1 = 436 ± 122 ms).CONCLUSIONS:Different tissue components of advanced intracranial plaques have distinguishable imaging characteristics with ultra-high-resolution quantitative MR imaging at 7T. Based on this study, the most promising method for distinguishing intracranial plaque components is T1-weighted imaging.

Ischemic stroke is one of the major diseases in the Western world, associated with high morbidity and mortality.^1,2 Identifying the cause of ischemic stroke is of great clinical importance, not only for deciding the best treatment options for the individual patient but also for possibly preventing future ischemic events, both recurrent and new.Intracranial atherosclerosis is one of the main causes of ischemic stroke and TIA worldwide, accounting for approximately 9%–33% of all ischemic strokes and TIAs (depending on race-ethnicity) and is the major cause of cerebral ischemic events in the Asian population. Additionally, the risk of recurrent ischemic stroke is increased in patients with underlying intracranial atherosclerosis.^3–8 Similar to extracranial atherosclerosis, for intracranial atherosclerosis, the degree of luminal stenosis is currently the main factor determining whether an atherosclerotic plaque is symptomatic and/or treatment is necessary. In the past decade, plaque composition has become an additional important feature in extracranial atherosclerosis management, enabling identification of specific culprit lesions requiring treatment, even when not causing significant stenosis.^9–12 However, for intracranial atherosclerosis, this is not yet common practice, even though the literature suggests that also intracranially, stenosis grade is not always associated with a risk of ischemic events: In patients with a high-grade stenosis, only 1 in every 5–10 patients will have a recurrent ischemic stroke.^5,6,13,14 This implies that like in extracranial atherosclerosis, luminal information is not the only important marker for future cerebrovascular events.In recent years, several high-resolution intracranial vessel wall imaging techniques using 3T and 7T MR imaging have emerged for the evaluation and characterization of atherosclerotic vessel wall lesions in vivo.¹⁵ However, these in vivo techniques so far have not been validated with histopathology, due to poor accessibility of the intracranial arteries. Therefore, the question arises if these techniques are truly able—ie, have enough image contrast—to distinguish different atherosclerotic plaque components. In the past 2 years, 2 ex vivo correlation studies have been performed at 7T MR imaging to assess its ability to visualize different intracranial atherosclerotic plaque components.^16,17 These ex vivo studies showed that 7T MR imaging is capable of identifying focal thickening of the intracranial arterial vessel wall and distinguishing different plaque components within advanced intracranial atherosclerotic plaques with different image contrast weightings. Recently, a first case report was published demonstrating the correlation between certain intracranial atherosclerotic plaque components visualized in vivo at 3T and histologic validation of the plaque postmortem.¹⁸ Those studies used qualitative MR images to score the atherosclerotic plaque signal heterogeneities. As a next step toward validation, quantitative assessment of MR signal characteristics of specific plaque components might enable more firm conclusions regarding the ability of T1-, T2-, T2*-, and proton density (PD)-weighted sequences in characterizing intracranial atherosclerotic plaques. Once it is known which plaque components can be identified with ex vivo MR imaging sequences, a translation can be made to in vivo intracranial vessel wall MR imaging, by developing sequences based on the nuclear magnetic resonance tissue properties of the identified atherosclerotic plaque components. In the current study, a multiparametric ultra-high-resolution quantitative MR imaging protocol was performed to identify the MR signal characteristics of different intracranial atherosclerotic plaque components, and using histopathology for validation.     

大范围扩散加权成像在3.0T MR的正常表现

恶性肿瘤具有向骨及其他组织侵犯的倾向,骨及其他组织转移瘤的诊断对于肿瘤的精确分期、确定预后及合理化治疗非常重要[1,2].骨扫描是目前最常用的检测骨转移瘤的方法,但特异性受限,敏感性也仅约62%～89%[3,4].     

1.5.T和3.0T磁共振检查在直肠癌术前分期价值的比较

目的:探讨1.5T和3.0T磁共振检查在直肠癌诊断和术前分期中的作用,分析两者在直肠癌术前分期的应用价值.方法:选择经肠镜活检证实为直肠癌病人60例,随机盲法均分为两组.分别行1.5T和3.0T磁共振检查及术前直肠癌影像分期,并与病理分期对照.结果:1.5T MRIT分期总准确性为80%,N分期总准确率为67%,N0分...