3.0T高时间分辨率对比增强MRA颅内血管成像

目的:评价3.0T高时间分辨率对比增强磁共振血管成像(TR 3DCE-MRA)在颅内血管成像的技术可行性和临床应用价值。方法:经医院伦理委员会批准,回顾性搜集21例患者,采用3.0T磁共振,首先行常规序列T1WI、T2WI和TOF MRA扫描,然后在确定病变处用TR 3DCE-MRA即快速小角度激发梯度回波序列(3DFLASH)。所有病例在检查后1～3d行高分辨率增强MRA(HR CE-MRA),测量动脉的信噪比和对比噪声比,由2位影像专家对TR CE-MRA和HR CE-MRA图像质量进行评价,分别对图像伪影、静脉污染、脑动脉显示效果进行评分。评分结果采用SPSS 13.0进行统计学分析,差异具有统计学意义(P<0.05)。结果:21例患者中动脉瘤3例,动静脉畸形7例,烟雾病2例,动脉狭窄9例。图像SNR和CNR测量均值分别为237±89和213±94,Wilcoxon test检验结果Z=-3.160,P=0.002<0.05,静脉污染组Z=-4.298,P=0.001<0.01,血管显示组Z=-4.491,P=0.001<0.01,差异有明显统计学意义。结论:TRCE-MRA比HR CE-MRA具有严重伪影少,没有静脉污染,良好的血管对比,能够同时评价动脉血管和静脉血管,将是颅内血管疾病的首选。     

低剂量钆对比剂3D CE-MRA 与 DSA 对肾动脉狭窄病变的诊断价值

肾动脉狭窄(renal artery stenosis,RAS)多由动脉粥样硬化、纤维肌发育不良及大动脉炎引起[1],是继发性高血压最常见的原因,可能会导致严重的肾功能损害[2]。数字减影血管造影(digital subtraction angiography,DSA)仍被认为是诊断与评价周围动脉病变的金标准,但因碘对比剂存在肾功能损害、射线损伤、高费用及创伤性等缺点,其应用逐步被磁共振血管成像(magnetic resonance angiography,MRA)代替[3]。三维增强磁共振血管成像(3D CE-MRA)克服了传统 MRA 的不足,其以无辐射、准确、安全的优点广泛应用于临床[4]。3D CE-MRA 是利用极短的 TR 和 TE 的快速梯度扫描序列,向血管内注入顺磁性对比剂,使血液的 T1弛豫时间明显变短而呈现高信号,达到血管成像的目的。3.0T 磁共振临床多应用于神经血管成像,凭借更高的信噪比,短的扫描时间,可获得更清晰的图像[5],钆对比剂量多为0.1~0.2 mmol/kg。但研究发现高剂量钆对比剂可能与肾源性系统性纤维化(NSF)有一定关系,且90%钆对比剂引起 NSF 患者剂量多>0.1 mmol/kg[6],因此,降低钆对比剂用量可降低其潜在的不良反应。3.0T MR 较1.5T MR 具有更高的信噪比与时间分辨率,提高图像质量,使降低对比剂量成为可能。本研究探讨低剂量钆对比剂3.0T MR 3D CE-MRA 对 RAS 的诊断价值。     

磁共振血管成像在脑血管病中的诊断价值

目的:探讨三维时间飞跃法MR血管成像(3D TOF MRA)和三维增强MR血管造影(3D CE-MRA)检查技术,评价两种方法对脑血管病的诊断价值。方法:磁共振血管成像检查150例,全部行3D TOF MRA检查;9例进行3D CE-MRA检查,钆对比剂(Gd-DTPA)0.2mmol/kg,注射流率3ml/s,增强前、增强后动脉期及静脉期3次扫描;所有MRA图像进行三维重建,同期12例行DSA检查。常规MRI包括横断面T1WI、T2WI,矢状面T1WI。结果:56例中颅内血管显示正常56例,颅内动脉狭窄或闭塞者46例,颅内动脉瘤22例,颅内动静脉畸形21例,颈内动脉海绵窦瘘3例,烟雾病(moyamoya dis-ease)2例。结论:3D TOF MRA和3D CE-MRA是无创、快速、有效的检查技术,对诊断脑血管病有较高的价值,结合原始图像和常规MRI检查,一次检查即能为临床提供较为全面的信息,可作为脑血管病的筛选和首选诊断方法。     

剖宫产切口瘢痕早期妊娠1例

患者女,33岁。停经42天伴轻微腹痛就诊。查血β-HCG增高。既往剖宫产1次,剖宫产方式为子宫下段横切口;腹部超声提示宫颈妊娠。磁共振检查使用Siemens公司NOVUS 1.5T扫描仪,相控阵体线圈,平扫常规行横断位二维FLASH序列T1WI、TSE序列矢状位T2WI脂肪抑制成像及冠状位trufi序列,T1WI:TR 133ms,TE 2.85ms;T2WI:TR 3 500ms,TE 80ms;trufi:TR 4.8ms,TE 2.4ms。横断位     

3.0T磁共振乳腺成像扫描参数的优化

目的 探讨不同参数对乳腺MRI图像质量及扫描时间的影响.方法 (1)采用GE Signa Excite 3.0T MR成像系统和8通道乳腺线圈,对3个新鲜手术乳腺标本进行多序列、多参数扫描,根据图像质量及扫描时间选择适合乳腺MR成像的扫描序列和参数.(2)对10名健康志愿者采用FSE-IR、抑脂和非抑脂 FSE-XL T1WI和抑脂FSE-XL T2WI序列及不同参数进行乳腺MR成像,测量比较不同参数图像的信噪比.结果 其它参数相同时,采用以下序列和参数进行乳腺MR成像可在较短的扫描时间内获得较高的图像质量,包括FSE-IR序列:TR 6000 ms、TI 190 ms、TE 42 ms、带宽62.50 kHz、NEX 1、扫描层数18;FSE-XL T1WI序列:TR 500 ms、TE 11.5 ms、带宽50 kHz、NEX 2、扫描层数18;FSE-XL T2WI序列:TR 4200 ms、TE 80 ms、带宽41.67 kHz、NEX 1、扫描层数18.结论 3.0T MR乳腺成像,通过扫描参数的优化可节约扫描时间、提高图像质量.     

小腿加压3.0T MRA评估糖尿病下肢血管病变的价值探讨

目的 以DSA为金标准评价小腿加压法3.0 T 增强磁共振血管成像(CE-MRA)在糖尿病下肢血管病变的应用价值.方法 对61例2型糖尿病合并下肢血管病变患者进行双下肢MRA检查,患者平均病程(11.6±6.0)年.使用3.0 T CE-MRA,其中小腿袖带加压后成像者(即加压组)31例,常规成像者30例(即常规组),...     

磁共振DWI、FLAIR序列和MRA在急性缺血性脑中风的临床应用

目的:探讨磁共振扩散加权成像(DWI)、FLAIR序列和磁共振血管成像(MRA)对急性缺血性脑中风的诊断价值。方法:选择97例急性脑中风患者,其中超急性期23例,急性期74例。全部患者均行脑MRI常规T1WI、T2WI序列、FLAIR序列、DWI和3D TOF MRA检查。结果:97例超急性及急性期脑中风的DWI阳性检出率为100%,FLAIR序列和3D TOFMRA的阳性检出率分别为75.3%和52.6%,常规T1WI、T2WI序列的阳性检出率分别为20.6%和34.0%。结论:对于早期脑梗死病灶,DWI比FLAIR序列敏感性高,更易于发现病灶,FLAIR序列对于脑白质变性以及脑室、脑池、脑沟周围病变观察满意,MRA在分析脑中风病因方面可提供更多的影像学信息,DWI、FLAIR序列和MRA是对常规序列的重要补充,值得临床推广应用。     

脊髓血管畸形病变磁共振成像技术分析

目的 探讨脊髓血管畸形(SVM)病变的磁共振成像技术方法及临床应用价值.方法 回顾分析16例椎管内SVM患者资料,并由DSA检查证实.使用GE Signa 1.5T EXCITE HD磁共振机,GE ADW4.3工作站进行图像后处理,磁共振脉冲序列:矢状面T1WI、T2WI,轴位T2WI及斜冠状面CE-MRA.扫描完后将数据传至工作站,进行图像后处理,观察椎管内SVM的磁共振影像学特征.结果 16例椎管内SVM中,椎管内血管流空现象是椎管内SVM特征性MRI表现,CE-MRA常显示为蚯蚓样或杂乱无章高信号影.结论 MR对诊断椎管内SVM病变安全可靠,可作为首选筛查方法.     

MRV检测脑静脉窦血栓的作用

目的探讨磁共振静脉血管成像(MRV)用于检测脑静脉窦血栓(CVT)的应用价值。方法8例CVT患者均行MRI标准自旋回波T1WI、T2WI和VEN/3D/PCA。结果VEN/3D/PCA比标准SE序列T1WI和T2WI多检测出CVT3处,与脑血管造影的结果完全相符。结论MRV可以准确无创的诊断CVT。     

门脉高压的三维增强磁共振血管成像

目的 探讨上腹部磁共振对比增强三维血管成像技术(three-dimensional contrast-enhanced MR angiography,3D CE-MRA),对显示门脉高压所致血管改变及血流改变的应用价值.方法 对60例门脉高压患者,运用GE Signa 1.5T超导磁共振扫描仪进行3D CE-MRA 和2D CE-MRA成像,分析门脉高压的MRA表现.结果 (1)门静脉纤细狭窄18例.(2)门静脉闭塞、海绵样变11例.(3)食管下段、胃底静脉曲张43例.(4)腔静脉狭窄、闭塞 11例.(5)奇静脉、半奇静脉开放4例.(6)脐静脉开放4例.结论 3D CE-MRA是诊断门脉高压所致门脉系统血管及血流改变的可靠方法.     

磁共振磁敏感成像技术在脑部血管畸形中的应用优势

目的探讨MRI磁敏感成像(SWI)技术在脑部血管畸形中的应用价值。方法对31例疑有脑部血管畸形的患者,应用MRI自旋回波T1WI、T2WI序列、SWI技术进行平扫,最小信号强度投影(MinIP)法图像重建。其中另有11例动静脉畸形和4例烟雾病者同时行MRA检查。结果31例患者均获得了清晰的畸形血管图像,其中海绵状血管瘤15例,动静脉畸形11例,烟雾病4例,静脉瘤1例。结论磁共振SWI技术的应用,大大提高了对脑部血管畸形疾病的诊断的准确性,对手术治疗有极大的指导作用。     

The role of time-resolved 3D contrast-enhanced MR angiography in the assessment and grading of cerebral arteriovenous malformations

Purpose

To assess the role of three-dimensional (3D) contrast-enhanced, time-resolved MR angiography (CE TR MRA) in patients with intracranial arteriovenous malformations (AVMs).

Methods

We studied 12 patient with intracranial AVMs on a 3.0 T MR imaging system (Magentom TIM Trio, Siemens Medical Solutions, Erlangen, Germany) using 3D CE TR MRA with autocalibrating partially parallel acquisitions and echo sharing schemes, which provided temporal resolution of 0.58 or 1.7 s and near isotropic voxels. We qualitatively assessed image quality of the 3D CE TR MRA and compared the grading of the AVMs based on modified Spetzler-Martin system for 3D CE TR MRA and catheter digital subtraction angiography (DSA).

Results

CE TR MRA provided good quality images in the 3 standard orthogonal planes, and good arterial-venous separation in all cases. All AVMs were correctly graded by CE TR MRA when compared with DSA.3D CE TR MRA provides a non-invasive alternative to DSA for the evaluation of cerebral AVMs.     

High spatial resolution contrast-enhanced MR angiography of the supraaortic arteries using the quadrature body coil at 3.0T: A feasibility study

To examine whether the the increased signal-to-noise (S/N) available at 3.0T would permit the use of the quadrature body coil for high spatial resolution contrast-enhanced (CE) MR angiography (MRA), and whether the large FOV that was used in our routine 1.5T protocol would also be feasible at 3.0T. In a prospective study, 43 patients and five volunteers were examined on a clinical whole-body 3.0T MR unit (Intera, Philips Medical Systems, Best, The Netherlands) after institutional review board approval and informed consent. Three-dimensional CE MRA (T1 gradient echo-sequence with TR/TE = 5.7/1.93 msec.; acquisition time, 1:54 min.) using randomly segmented central k-space ordering (CENTRA) was acquired with the quadrature body coil, using over a FOV of 350 mm. A high-image matrix of 432×432 yielded a non-zero filled voxel size of 0.81 mm × 0.81 mm × 1.0 mm (0.66 mm³). For quantitative analysis, contrast ratios (CR) between vessels (S) and signal in surrounding tissue (ST) were calculated [(S−ST)/(S+ST)]. For qualitative analysis, image quality and presence of artifacts were rated by two radiologists in consensus on a five-point scale (1=excellent to 5=nondiagnostic). Digital subtraction angiography (DSA) served as the standard of reference in patients with vascular disease. In the five volunteers, 1.5T CE MRA using a phased array neurovascular coil was available for intraindividual comparison. 3.0T CE MRA was successfully performed in 48/48 subjects (100%). Mean CR± SD were 0.76 (139.30/182.42) and 0.87 (235.18/270.14) at 3.0T and 1.5T respectively .Mean image quality was 3.82±0.86. Intraindividual comparison between 1.5T and 3.0T CE MRA in the volunteers revealed no significant difference in image quality (4.2±0.74 vs 4.6±0.80; p>0.05). Vascular disease was correctly identified in 13/13 patients with DSA correlation. CE MRA of the supraaortic arteries is feasible at 3.0T using a large FOV of 350 mm. The signal gain at 3.0T enables high spatial resolution contrast-enhanced MR angiography by using the built-in quadrature body coil only.     

Contrast-enhanced MR angiography of the carotid and vertebrobasilar circulations

BACKGROUND AND PURPOSE: Contrast-enhanced MR angiography (CE MRA) is a proven diagnostic tool in evaluation of the carotid arteries; however, few studies have addressed its accuracy in the vertebrobasilar system. The purpose of this study was to assess the sensitivity and specificity of CE MRA compared with digital subtraction angiography (DSA) for detection of vertebrobasilar disease. METHODS: Forty patients with suspected atherosclerotic disease of the carotid and vertebrobasilar circulations underwent CE MRA on a 1.5 T MR imaging scanner by use of a coronal 3D gradient-echo pulse sequence after intravenous injection of gadolinium diethylene triamine penta-acetic acid. All patients had correlative DSA within a 1-month period. CE MRA images were randomized and then independently assessed by 2 observers who were blinded to the DSA results. DSA examinations were analyzed in a similar manner. Each observer was asked to report the presence or absence of clinically significant stenosis (>50%), occlusion, fistula, aneurysm, and dissection. The MRA findings were then correlated with DSA. RESULTS: The sensitivity and specificity of MRA for detection of disease in the entire carotid and vertebrobasilar systems were 90% and 97%, respectively; for the carotid system alone, the sensitivity and specificity were 94% and 97%, respectively; and for the vertebrobasilar system they were 88% and 98% respectively. The overall interobserver reliability was 98% (kappa = 0.92). CONCLUSION: CE MRA is accurate at detecting disease not only in the carotid vessels, but also in the vertebrobasilar circulation, and has the potential to provide a comprehensive and noninvasive evaluation of the head and neck arteries in a single study.     

颈动脉三维增强磁共振血管成像技术初步探讨

目的　探讨颈动脉三维增强磁共振血管成像 (3DCEMRA)方法和影响图像质量的因素。方法　使用 1.5T超导型MR扫描机 ,头部、颈部以及部分腰椎相控阵线圈。对 48例病人进行颈动脉 3DCEMRA增强扫描。检查时 ,嘱患者屏气 ,于静脉内团注钆双胺 (Gd -DTPA -BMA)对比剂后进行颈动脉期扫描 ,用 3DFLASH序列采集图像。结果　检查的病例 96%获得了满意的图像 ,经MIP和MPR重建后 ,能够清楚显示颈动脉正常解剖结构和病变的部位、大小及其狭窄程度。 2 3例经数字减影血管造影(DSA)或 /和超声以及手术证实的病例中 ,3DCEMRA显示颈动脉的特异性和敏感性均为 10 0 %。结论　高质量的颈动脉MRA图像依赖于注药后扫描时机的准确性 ,注药流速与总量的合理性 ,合适的扫描序列 ,以及操作者的技巧和熟练程度     

32通道线圈在3.0 T MR对比增强全心冠状动脉成像中的初步应用

目的 评价32通道线圈高并行采集加速3.0 T MR对比增强全心冠状动脉成像(CECMRA)技术的临床应用价值.方法 对拟诊冠心病的60例患者进行32通道线圈3.0 T CE CMRA检查,成像采用心电门控、呼吸导航、扰相位梯度回波序列,加用非选择性反转回波抑制心肌信号,TT为200 ms.以全心覆盖和并行采集方式获取图像数据.增强扫描采用钆贝葡胺(Gd-BOPTA,0.15 mmoL/kg)慢速静脉注射(0.3 ml/s).以X线冠状动脉造影结果作为参考标准,采用四格表χ2检验,评价CE CMRA诊断冠状动脉≥50%狭窄的诊断准确性.结果 60例患者中56例成功完成3.0 T CE CMRA,平均扫描时间为(6.0±1.3)min.CE CMRA在28例患者正确检出至少1个有意义狭窄,其诊断敏感性为93.3%.在26例CAG除外冠心病的患者中,CMRA正确排除了23例,其诊断特异性为88.5%.结论 应用32通道相控阵线圈行高并行采集加速3.0 T CE CMRA检查,可以在减少对比剂用量的同时缩短扫描时间,提高诊断准确性.     

用自制线圈对大鼠单侧输尿管梗阻行磁共振成像的可行性研究

目的：探讨用自制3in表面线圈在3．0TMR上进行大鼠肾积水成像的可行性。方法：5只Wistar大鼠制备单侧输尿管梗阻模型,于第5天和第10天分别行T1WI、T2WI,扩散加权（DWI）和MR尿路造影（MRU）检查。使用GE3．0TMR扫描仪,3英寸自制表面线圈。两名医师分别独立评价各序列图像质量,一名医师测量两次扫描梗阻侧肾实质厚度和肾盂宽度。结果：两观察者均认为T1WI和T2WI有10／10图像质量为“好”,T1WI中“优”分别为7／10和6／10;T2WI中“优”分别为8／10和7／10;两观察者均认为DWI有8／10达到“好”,3／10达“优”;MRU中“优”分别为6／10和5／10。第5天到第10天梗阻侧肾积水程度显著加重（P〈0．05）。结论：自制的三英寸线圈在3．0TMR上进行肾积水大鼠模型常规T1WI、T2WI和DWI成像能够获得较满意的图像,满足大鼠肾积水实验对积水程度观测的需求。     

肾动脉高分辨力三维增强磁共振血管成像术:透视触发和并行采集技术使用初探

目的:评估透视触发和并行采集技术用于肾动脉高分辨力三维增强磁共振血管成像术的可行性和对肾动脉的显影诊断效果。方法:90例临床诊断或怀疑肾动脉或腹主动脉病变的患者行高分辨力肾动脉三维增强磁共振血管成像(3D CE MRA)。使用透视触发软件启动肾动脉3D CE MRA扫描,扫描采用K空间中心填充法和加速因子为2的并行采集技术。分析图象质量和病变显示情况,并与其它检查结果对照。结果:肾动脉3D CE MRA显示了90例患者共810支动脉段(100%显示率),平均显示等级为3.88。3D CE MRA显示8例11支副肾动脉,显示等级均为4.0。肾动脉段级分支的显示率为73%(66/90例)。所有病例在动脉显示区静脉均未显影或显影很淡,平均等级为0.20。3D CE MRA发现639支动脉段正常;66支动脉段管壁不规则;55支动脉段轻度狭窄;37支动脉段严重狭窄;2支动脉段闭塞;11支动脉段动脉瘤形成。其中96支肾动脉存在狭窄,11支副肾动脉均正常。共有43例病例,肾动脉3D CE MRA与其它血管成像技术作了比较,3D CE MRA的检查结果与之完全符合。结论:透视触发并行采集肾动脉高分辨力3D CE MRA简单可行,成像时间短,空间分辨力高,能清楚显示肾动脉且无静脉污染。     

3.0T MR颈动脉成像技术

目的：探讨颈动脉“亮血”3D-TOF MRA配合“黑血”血管壁MR成像技术对血管病变显示的能力。方法：采用颈动脉专用表面线圈,对31例疑有颈动脉病变的脑卒中患者行MR多序列(“亮血”3D-TOF、“黑血”T1WI、T2WI)检查,并进行颈动脉狭窄程度和病变分类,比较“亮血”序列和“黑血”序列检测的阳性率。结果：31例受...