快速与标准三维时间飞跃法MRA在颅内动脉成像的对比研究

目的评价快速三维时间飞跃法(3D fast time of flight,3D Fast-TOF)磁共振血管成像(magnetic resonance angiography,MRA)在颅内动脉成像中的临床应用价值。材料与方法对34例临床怀疑脑血管病变的患者同时进行标准3D TOF MRA和3D Fast-TOF MRA序列进行脑部动脉成像,其中,2例不能同时顺利完成3D Fast-TOF MRA和标准3D TOF MRA扫描,1例由于运动伪影、图像质量较差,未纳入统计。共31例检查者(男15例,女16例)顺利完成扫描,采用MIP进行三维重建。分别测得原始横断位基底动脉中段和同层脑桥信号并计算图像的信噪比和对比噪声比,对颈内动脉的各级分支显示和图像质量进行评分,对二者的图像质量、血管分支、信噪比(signal to noise ratio,SNR)和对比噪声比(contrast to noise ratio,CNR)进行评分。结果3D Fast-TOF MRA组的颈内动脉分支显示评分为(3.21±0.86)分,标准3D TOF MRA组为(2.51±0.64)分,两组间具有统计学差异(P＜0.01),3D Fast-TOF MRA组显示血管分支优于标准序列。3D Fast-TOF MRA组图像质量为(4.84±0.58)分,标准3D TOF组图像质量为(4.87±0.56)分,3D Fast-TOF MRA组的SNR、CNR分别为161.17±11.72、124.13±11.28;标准3D TOF组的SNR、CNR分别为149.39±39.91、113.04±29.90;两组间图像质量、SNR、CNR无显著性差异(P＞0.05),3D Fast-TOF MRA序列扫描时间3.31 min,标准扫描序列扫描时间5.28 min。结论3D Fast-TOF MRA成像技术具有良好的图像质量、较高的空间分辨率,与标准3D TOF序列相比,扫描时间明显缩短,可以作为一种新的磁共振颅内动脉成像技术。     

对比三维多回波T2*血管成像与三维时间飞跃法MR血管成像诊断大脑半球梗死患者颅内大血管病变

目的 探讨三维多回波T2^*血管成像(3D SWAN)诊断大脑半球梗死患者颅内大血管病变的价值。 方法 对63例单侧脑梗死患者(起病时间为3 h~8天)行常规MR、DWI、3D SWAN及三维时间飞跃法MR血管成像(3D TOF MRA)检查,分析3D SWAN检测的颅内大动脉(包括大脑中动脉和颈内动脉颅内段)异常低信号,与3D TOF MRA显示的异常(中断、闭塞、狭窄)进行比较,判断两种方法对显示动脉异常的一致性,并计算Kappa值。 结果 3D TOF MRA共显示28条大脑中动脉、9条颈内动脉中断、闭塞或狭窄,而3D SWAN则显示其中30条动脉出现异常低信号,3D SWAN与3D TOF MRA对显示大脑中动脉和颈内动脉颅内段的异常具有很好的一致性(Kappa值为0.867,P＜0.05)。 结论 3D SWAN对诊断脑梗死患者大脑中动脉和颈内动脉颅内段异常有较高价值,分析3D SWAN动脉内异常低信号的特点有助于进一步判断3D TOF MRA显示的动脉中断、闭塞、狭窄的原因。     

磁共振3D FIESTA结合3D TOF MRA序列对诊断听神经血管压迫综合征的价值

目的：探讨MRI三维循环相位稳态采集快速成像（3D FIESTA）序列结合三维时间飞跃磁共振血管成像（3D TOF MRA）序列在诊断听神经血管压迫综合征中的价值。材料与方法：回顾性研究2008年6月－2010年6月在我院初诊为听神经血管压迫综合征的患者40例,对照组40例均无临床症状,所有患者均接受MRI检查（包括3D FIESTA和3D TOF MRA）。由两位神经系统影像学专家一同分析磁共振3D FIESTA和3D TOF MRA序列中听神经和邻近血管的走行关系,评价两序列相结合对显示压迫或接触听神经的血管的优势,并分析病变与临床症状相关性,使用SPSS 16.0软件包进行χ2检验,P<0.05被认为差异具有统计学意义。结果：40例患者中,3D FIESTA结合3D TOF MRA序列显示听神经存在邻近血管压迫或接触者37例,无压迫或接触者3例,结合两序列可以清晰显示异常血管来源及走行;与对照组比较,MRI图像显示听神经血管压迫或接触与临床症状存在密切关系,有统计学差异。结论：磁共振3D FIESTA结合3D TOF MRA可清晰显示听神经血管压迫及血管情况,诊断阳性率高,并且与临床症状具有良好的相关性,对于术前评价有重要作用,3D FIESTA及3D TOF MRA序列扫描时间短,图像质量高,应列入中内耳部位的常规扫描序列。     

3.0 T MRI对儿童动脉性缺血性脑卒中的诊断价值

目的探讨MR的常规扫描序列、扩散加权成像(DWI)和非增强时间飞跃法血管成像(3D TOF MRA)对儿童动脉性缺血性脑卒中(arterial ischaemic stroke,AIS)的诊断价值。材料与方法对18例有临床症状且同时行MRI检查并确诊为AIS的患儿进行回顾性分析。所有患儿均同时行MR常规扫描序列(包括T1WI、T2WI和T2-FLAIR)、DWI和3D TOF MRA扫描。结果 18例患儿7例发病前有感染史,3例有外伤史,1例合并布卡综合征和先天性心脏病,1例合并唐氏综合征(21-三体综合征),1例有脑颜面血管瘤综合征。MRI共检出梗死灶53处,DWI示16例存在急性期病变。9例为多脑叶梗死,4例为大面积脑梗死,1例无脑梗死病灶。MRA检查示15例患儿存在血管狭窄或闭塞,8例为局限性的血管病变,7例为烟雾病。共检出血管狭窄34处,血管闭塞3处。结论 MR常规扫描序列和DWI结合非增强3D TOF MRA可全面评价儿童动脉性缺血性脑卒中的部位和血管狭窄的程度及发病时间。     

基于mDixon新型MR血管成像序列用于颈部动脉成像的可行性

目的 基于将放射状k空间填充及压缩感知技术融合于mDixon技术开发一种新型MR血管成像(MRA)序列(3D mDixon-MRA),观察其用于颈部动脉成像的可行性。方法 前瞻性收集45例疑诊颈部动脉疾病患者，以3D时间飞跃法采集颈部动脉MRA(3D TOF-MRA)及3D mDixon-MRA,比较颈总动脉根部和中远段、椎动脉根部和中远段及颈内外动脉根部在2种图像中的信噪比(SNR)和对比度噪声比(CNR),以及2种图像质量主观评分的差异。结果 3D mDixon-MRA所示各动脉SNR均显著高于3D TOF-MRA(P均<0.01)。颈总动脉根部CNR在2种图像中的差异无统计学意义(P=0.13),其余动脉在3D mDixon-MRA中的CNR均显著高于3D TOF-MRA(P均<0.01)。颈总动脉根部、椎动脉根部及椎动脉中远段在3D mDixon-MRA中的主观评分均高于3D TOF-MRA(P均<0.05),其余动脉在2种图像中的主观评分差异均无统计学意义(P均>0.05)。结论 3D mDixon-MRA序列可用于颈部动脉成像，有利于提高图像质量、缩...     

三维时间飞跃法磁共振血管成像与数字减影血管造影诊断基底动脉狭窄的一致性分析

目的使用统计学方法评估三维时间飞跃法磁共振血管成像(3D TOF MRA)和金标准数字减影血管造影(DSA)诊断基底动脉狭窄一致性。方法回顾性分析70例基底动脉狭窄患者的3D TOF MRA和DSA图像。把图像质量分为优、良、差三级,使用盲法评估血管狭窄程度,狭窄率≥50%的病变定为严重狭窄。MIP图像和原始图像相结合评估基底动脉病变狭窄程度,在原始图像上测量狭窄率。利用MEDCALC12.0软件进行统计学分析。使用Wilcoxon配对秩和检验衡量MRA和DSA狭窄率的差异;计算Spearman秩相关系数评价二者之间相关性;使用Bland-Altman图法比较二者测量结果的一致性。并计算诊断严重狭窄的敏感度、特异度、阳性似然比、阴性似然比、患病率、阳性预测值和阴性预测值,绘制ROC曲线。结果 MRA上38条基底动脉严重狭窄,DSA上35条动脉严重狭窄。MRA测得的基底动脉狭窄率(52.57±22.79)%稍大于DSA上测得的狭窄率(51.84±23.20)%,二者比较无统计学差异(P=0.152);相关性强(r=0.985,P<0.001);Bland-Altman图显示较强的一致性,95.71%(67/70)的点位于一致性界限内。敏感度、特异度、阳性似然比、阴性似然比、患病率、阳性预测值、阴性预测值分别为94.29%、85.71%、6.6、0.07、50.00%、86.84%、93.75%。ROC曲线下面积为0.9(P<0.001)。结论和DSA相比,3D TOF MRA的诊断基底动脉狭窄的具有很好的一致性。     

三维动态增强磁共振血管成像诊断下肢血管病变65例分析

目的探讨三维动态增强磁共振血管成像(3D CE-MRA)对下肢血管病变的诊断意义。方法对65例疑有下肢血管病变的患者行全下肢血管动、静脉3D动态扫描成像。使用GE1.5T超导磁共仪,采用Body coil正交线圈,运用M3D/TOF/FSPGR/25扫描序列自动移床三段采集双下肢动、静脉血管图像。结果 59例图像显示清晰、直观、完整,显示体部及下肢血管的正常解剖结构和各种病变;6例扫描时间掌握不佳,血管影像显示较差。结论 3D CE-MRA对全下肢血管病变显示有独特的优势,具有无创、无辐射,可作为下肢血管病变的主要检测手段。     

血管压迫性三叉神经痛的MR成像序列选择

大部分三叉神经痛是三叉神经脑池段的神经血管压迫(Neuro vascular compression,NVC)所致 [1],微血管减压术是此种原因所致三叉神经痛的有效治疗方法.影像上精确地显示三叉神经与周围血管的关系,对于血管压迫性三叉神经痛的诊断及微血管减压术至关重要.MRI是三叉神经痛的主要影像学检查方法,文献资料颇多.文献中应用最多的MR成像序列是3D FSE T2WI及TOF MRA,由于该成像序列固有的缺点,其对NVC显示的敏感性及特异性一直存在争议.     

钆贝葡胺三维动态增强磁共振血管成像对活体肝移植供体术前血管系统的评价

目的 钆贝葡胺增强三维动态增强磁共振血管成像(3D DCE MRA)对活体肝移植供体肝动脉、门静脉、肝静脉血管解剖的显示情况.方法 32例肝移植供体,术前常规MR扫描.首先经静脉注入1 ml钆贝葡胺注射液,行testbolus测出循环至肝动脉时间,然后行冠状位三维T1加权快速扰相小角度梯度回波(3D-FLASH)序列扫描,自动脉期开始连续扫描4期,每期间隔10 s,获得肝动脉、门静脉、肝静脉等各期图像,观察原始图像及MIP重建后图像中肝动脉、门静脉、肝静脉及其分支的显示情况,确定血管的走形及有无变异.以肝移植术中观察的血管情况作为金标准,分析MRA所见.结果 MRA对于肝动脉、门静脉、肝静脉系统的显示质量均较好.MRA发现肝动脉变异5例,门静脉变异4例,肝静脉变异8例,均经过手术证实.术中发现副肝动脉1例,MRA未发现.结论 钆贝葡胺3D DCE MRA安全、无创,对肝动脉、门静脉、肝静脉显示清楚,诊断变异准确度高,有可能成为术前肝移植供体血管评价的首选影像学检查手段.     

MRA和DSA探测颅内动脉瘤的比较研究

目的：研究MRA探测颅内动脉瘤的准确性及其影响因素。方法：我们搜集30例病人,其中20例有近期SAH,全部病例都行3D TOF MRA和DSA检查。回顾性分析3D TOF MRA和SE MRI图像,并与其DSA表现相比较,分析MRA显示动脉瘤的敏感性。结果：DSA显示了全部病例的30个动脉瘤,3D TOF MRA显示25个动脉瘤（1个假阳性）,6个动脉瘤未显示,1例误诊为动脉瘤。MRA显示动脉瘤的敏感性为80%,假阳性为4%。漏诊动脉瘤多位于C1-2或后交通动脉起始部,直径在5mm以下。结论：3D TOF MRA是显示颅内动脉瘤的敏感方法之一,动脉瘤的大小和局部出血影响动脉瘤的清晰显示,动脉瘤的发生部位亦可能与显示有关。     

An autostereoscopic 3D display can improve visualization of 3D models from intracranial MR angiography

Purpose  

An autostereoscopic display with image quality comparable to ordinary 2D displays has recently been developed. The purpose of our study was to evaluate whether the visualization of static 3D models from intracranial time-of-flight (TOF) MR angiography (MRA) was improved by this display.     

3D-T2-DRIVE联合3DTOFMRA诊断面听神经微血管压迫的意义探讨

目的探讨应用3D-T2-DRIVE联合3D TOFMRA诊断面听神经血管性压迫的意义。材料与方法 36例临床拟诊面听神经血管压迫患者行3D-T2-DRIVE与3D TOFMRA序列的各向同性和等体素扫描,观察各例原始图和各方位重组图,评价其显示患侧面听神经、责任血管的效果,由差至优分别记0~3分。分别比较3D-T2-DRIVE、3D TOFMRA及3D-T2-DRIVE+3D TOFMRA三种方法在显示患侧面听神经、责任血管的差异。结果行Kruskal-Wallis H检验,以P0.01为差异有统计学意义。结果在显示面听神经方面,3D-T2-DRIVE+3D TOFMRA优于3D TOFMRA(H=58.78,P=0.0000),T2-3D-DRIVE优于3D TOFMRA(H=53.18,P=0.0000),3D-T2-DRIVE+3D TOFMRA、T2-3D-DRIVE间差异无统计学意义(H=2.28,P=0.1313);在显示责任血管方面,3D-T2-DRIVE+3D TOFMRA优于T2-3D-DRIVE(H=54.12,P=0.0000)和3D TOFMRA(H=62.42,P=0.0000),3D-T2-DRIVE与3D TOFMRA间差异无统计学意义(H=0.0083,P=0.9274)。36例中,3D-T2-DRIVE+3D TOFMRA检出面听神经根性细动脉压迫阳性32例,阴性4例,分别为手术和随访证实,诊断灵敏度100%,特异度100%。结论 3D-T2-DRIVE联合3D TOFMRA技术是诊断面听神经血管压迫性病变的精准方法。     

A study of in vitro and in vivo MR of free-breathing whole-heart 3D coronary angiography using parallel imaging

To evaluate parallel-imaging methods in free-breathing whole-heart 3D coronary magnetic resonance angiography and assess the navigator techniques and visualization rates of the major coronary arteries. We compared key parameters of the generalized autocalibrating partially parallel acquisition and modified sensitive encoding images in vitro phantom MRI; performed the MRA with GRAPPA parallel imaging in healthy volunteers; compared 1D- and 2D-prospective acquisition correction and analyzed the differences; and evaluated the visualization of major coronary arterial branches. GRAPPA images had higher signal-to-noise ratio and contrast-to-noise ratio and fewer aliasing artifacts. The coronary arteries were adequately visualized in 38 volunteers. 2D-PACE had a higher navigator efficiency, shorter scan time, and gave clearer reconstructed images in comparison with 1D-PACE. GRAPPA images were superior to mSENSE images. Whole-heart 3D coronary MRA along with parallel-imaging technique is a potential clinical method, and 2D-PACE is a better navigation technique than 1D-PACE.     

A study of in vitro and in vivo MR of free-breathing whole-heart 3D coronary angiography using parallel imaging

To evaluate parallel-imaging methods in free-breathing whole-heart 3D coronary magnetic resonance angiography and assess the navigator techniques and visualization rates of the major coronary arteries. We compared key parameters of the generalized autocalibrating partially parallel acquisition and modified sensitive encoding images in vitro phantom MRI; performed the MRA with GRAPPA parallel imaging in healthy volunteers; compared 1D- and 2D-prospective acquisition correction and analyzed the differences; and evaluated the visualization of major coronary arterial branches. GRAPPA images had higher signal-to-noise ratio and contrast-to-noise ratio and fewer aliasing artifacts. The coronary arteries were adequately visualized in 38 volunteers. 2D-PACE had a higher navigator efficiency, shorter scan time, and gave clearer reconstructed images in comparison with 1D-PACE. GRAPPA images were superior to mSENSE images. Whole-heart 3D coronary MRA along with parallel-imaging technique is a potential clinical method, and 2D-PACE is a better navigation technique than 1D-PACE.     

三种TOF法MRA诊断实验性动脉瘤的对比分析

目的：比较分析三种ＴＯＦ法ＭＲＡ的图像质量，以及不同成像技术对动脉瘤的诊断价值。材料与方法：用静脉囊镶嵌法将１８只犬制成三种类型（单侧型、分叉型、末梢型）颈总动脉囊状动脉瘤模型，术后２周分别进行ＩＡＤＳＡ、２ＤＴＯＦ、单层块３ＤＴＯＦ、薄块多层重叠技术（ＭＯＴＳＡ）ＭＲＡ检查。结果：以ＩＡＤＳＡ图像为标准，２ＤＴＯＦ、单层块３ＤＴＯＦ、ＭＯＴＳＡＭＲＡ都能显示动脉瘤的位置、形态、类型、大小、瘤颈、瘤体伸展方向。其中以ＭＯＴＳＡＭＲＡ图像最具评价能力，显示动脉瘤的形态、类型、瘤颈优于２ＤＴＯＦ、单层块３ＤＴＯＦ，不足之处图像有层块梯阶样伪影。三种ＴＯＦ成像技术对动脉瘤内缓慢血流、湍流、血栓、大动脉瘤有不同程度的信号丢失。结论：三种ＴＯＦ法成像技术中，ＭＯＴＳＡ技术最有利于作为临床３ＤＴＯＦ法ＭＲＡ检查颅内动脉瘤的常规成像技术。     

3D multi-scale vessel enhancement filtering based on curvature measurements: application to time-of-flight MRA

In this paper we evaluate the use of voxel intensity curvature measurements to enhance vessels in 3D MRA images. We compare a multi-scale discrete kernel filter (MaxCurve) to the Hessian matrix based filter proposed by Frangi and co-workers. The MaxCurve filter is based on the maximum difference between the negative curvature computed along orthogonal lines defined by a 3x3x3 kernel. Filter performance is assessed using measures of vessel and background separation (contrast and the area under the ROC curve). Filter parameters are optimized using a training set of four typical time-of-flight MRA images and tested on a separate set of ten MRA images with the same acquisition parameters. The filters tended to provide good MIP image contrast enhancement. The filters are applied to MRA images acquired with different parameters and field strengths indicating potential usefulness for a variety of images. Overall the discrete kernel and Hessian matrix filter performed quite similarly.     

Contrast-enhanced MR angiography of the intracranial circulation

NCE MRA can provide the authors with useful diagnostic information in patients suffering from intracranial vascular disease, often leading to improved or altered treatment decisions. Most centers have used 3D TOF for evaluation of stroke-the most common cerebral vascular disease. Because of slow and disturbed flow, conventional 3D TOF MRA tends to overestimate stenotic lesions and occluded arteries and this can confound neurovascular assessment in stroke patients. Post contrast 3D TOF techniques provide a more robust and more specific method for imaging the intracranial circulation that overcomes the drawbacks of conventional 3D TOF. In the setting of acute ischemic stroke, the authors have found that the combination of conventional and CE 3D TOF MRA improves their overall diagnostic ability. Dynamic and time-resolved CE MRA techniques have evolved rapidly. Time-resolved CE MRA, in particular, is emerging as a useful technique for imaging dynamic vascular pathologies such as AVMs. Unfortunately, time-resolved MRA of the intracranial circulation provides images with low spatial resolution and is currently limited to subsecond frame rate 2D acquisitions, and less than 2 seconds frame rates for 3D acquisitions. Nevertheless, like in other vascular regions, CE MRA represents a milestone for non-invasive intracranial vascular imaging. The continuing development of CE MRA techniques and of new contrast agents will lessen the need for intra-arterial angiography in the future.     

低场强回波3DTOFMRA容积扫描在头部病变的应用

目的探讨低场强MRA在头部病变的临床应用价值。方法39例病变均于PROVIEW0.23T开放式磁共振扫描仪检查。包括脑动脉硬化12例,胶质瘤10例,动静脉畸形6例,动脉瘤3例,垂体瘤2例,小脑髓母细胞瘤2例,脑膜瘤2例,海绵窦段假性动脉瘤1例,钩端螺旋体脑病1例。方法为3D-TOF。结果12例脑动脉硬化MRA均显示大脑前、中、后动脉管径变细,血管分支减少,颅内肿瘤16例均于静脉注射造影剂后使用3DTOFMRA,可见邻近血管移位及部分肿瘤供应血管。1例钩端螺旋体脑病的MRA中左侧大脑中动脉及其分支未见显示。6例动静脉畸形中4例清晰显示了畸形血管团及供血动脉和引流静脉。3例动脉瘤位于大脑前动脉分叉处。1例右侧海绵窦假性动脉瘤MRA显示右侧颈内动脉海绵窦段明显受压推移并管腔变窄。结论选择合适的血管成像序列,低场强MRA在头部病变中有较大的临床应用价值。     

低场强磁共振三维时飞法脑血流成像临床应用的初步报告(附52例分析)

作者收集了诊断明确的５２例颅内病变的低场ＭＲＡ资料进行分析，其中的２１例经Ｘ线脑血管造影检查；５２例均采用３ＤＴＯＦ法ＭＲＡ扫描；本组５２例中可１００％的显示Ｗｉｌｌｉｓ血管环及其附近４公分以内的血管段，额极动脉以前及侧裂动脉主干可清晰显示者达６９．２％（３２／５２）；５２例中３１例为脑血管疾病，诊断率为４８．４％（１５／３１），Ｘ线脑血管造影的诊断率为７６．２％（１６／２１）；由于低场强３ＤＴＯＦ法脑血流成像具有无创、无痛、安全、成像快捷等优点，所以可作为脑血管疾病的初查、筛选或作为不能接受ＤＳＡ检查的患者的诊断手段；作者还指出了与高场强ＭＲＡ相比低场强ＭＲＡ的不足之处。