多种MR血管造影对四肢血管性疾病和血管狭窄模型的应用研究

目的：通过多种MR血管影影技术在模拟狭窄血管的体外模型和四肢血管性疾病中的应用分析,评估其价值和限度。方法：（1）实验研究：对不同狭窄程度、长度的模型行二维时间飞跃磁共振血管造影（2D TOF MRA）、幅度对比磁共振血管造影（MCA）、增强（CE）MCA和三维增强磁共振血管造影（3D CE MRA）,测量并计算狭窄程度、长度及其对狭窄程度评估的准确性。（2）临床应用：对20例四肢血管性疾病的患者行3D CE MRA、2D TOF MRA和MC MCA,其中血管瘤12例,动脉粥样硬化4例,假性动脉瘤1例,脂肪瘤1例,骨转移瘤1例,动脉破裂修补术1例,均经手术病理证实。比较上述MRA的图像质量和血管显示情况。结果：（1）实验结果：2D TOF MRA、MCA、CE MCA和3D CE MRA对管腔狭窄程度为69％的分级准确性分别为36．4％、9．1％、18．2％和72．7％,3D CE MRA对狭窄＞69％的评估优于其他MRA方法（P＜0．001）,但比起真实值仍有高估（P＜0．001）。（2）临床应用：2D TOF MRA、MCA和3D CE MRA的动脉显示率分别为92．6％,94．4％和98．1％;对12例血管瘤的异常血管显示分别为0例、6例和11例。结论：3D CE MRA无论对图像质量、狭窄程度的评估还是对病灶的供血血管及病灶与血管关系的显示均具有明显优势,但对狭窄程度的高估仍不可避免。     

MRA对外周血管闭塞性疾病评估的体外研究

目的：提高对外周动脉狭窄的MRA征象的认识和分析能力。方法：对不同狭窄程度和狭窄长度的模型行2DTOFMRA、MCA、CEMCA和3DCEMRA检查，并与造影结果和真实值对照。结果：2DTOFMRA、MCA、CEMCA和3DCEMRA对明显狭窄（69％）的分级准确度分别为36．4％、9．1％、18．2％和72．7％。3DCEMRA对明显狭窄（≥50％）的狭窄程度的评估优于其他MRA方法（均P＜0．001），但与造影和真实值比仍有高估（均P＜0．001）。对狭窄长度的评估2DTOFMRA明显高估（P＜0．001），3DCEMRA评估价值与造影和真实相当（均P＞0．05）。结论：3DCEMRA无论是图像质量、狭窄程度的评估还是狭窄长度的测量均有明显优势，但对狭窄程度的高估仍不可避免，需积累经验以提高诊断的准确性。     

增强与门控二维时间飞跃法MR血管造影评价颈内动脉狭窄的对比研究

目的：评价对比剂增强MR血管造影（CE MRA）与心电门控二维时间飞跃法（Gated 2D TOF)MRA评价颈内动脉狭窄的准确性。方法：34例怀疑有颈内动脉狭窄的病人（男27例,女7例,年龄45－78岁）均接受了CE MRA、Gated 2D TOF MRA和DSA检查。MRA图像采用最大强度投影法重建后与DSA进行对比。评价两种MRA方法的敏感性、特异性、诊断准确性、高估狭窄和低估狭窄的情况。结果：（1）34例68条颈内动脉中,DSA诊断23条为正常,45条呈不同程度狭窄或闭塞,其中轻度狭窄10条、中度14条、重度17条、闭塞4条。CE MRA与DSA结果一致者66（97％）,2条高估。Gated 2D TOF MRA与DSA诊断一致者为56条（82％）,其中高估9条,低估3条。（2）以正常和狭窄或闭塞为判断点时,CE MRA较Gatde 2D TOF MRA的敏感性、特异性和诊断准确性高,分别为100％、100％、100％与95．6％、78．3％、89．4％。（3）以70％狭窄为判断点时,CE MRA与Gated 2D TOF MRA的敏感性、特异性和诊断准确性分别为100％、97．8％、98．5％与95．2％、93．6％、94．1％。Gated 2D TOF MRA与DSA比较的χ^2=3.000,P=0.083;CE MRA与DSA比较的χ^2=2.000,P=0.157;而Gated 2D TOF MRA与CE MRA比较的χ^2=1.600,P=0.206。结论：与Gated 2D TOF MRA相比,CE MRA评价颈动脉狭窄更可靠。     

3D TRICKS MRA对颈动脉粥样硬化狭窄的诊断价值

目的：探讨3D TRICKS MRA对颈动脉粥样硬化狭窄的诊断价值。方法：对43例临床疑诊颈动脉粥样硬化狭窄的患者行2D TOF MRA和3D TRICKS MRA检查,其中31例同期行DSA检查,以颈总动脉法（CC法）计算狭窄率。结果：颈动脉闭塞2支,重度狭窄10支,中度狭窄31支,轻度狭窄25支,正常18支。2D TOF MRA、3D TRICKS MRA与DSA对照,显示狭窄部位均与DSA所示相符。2D TOF MRA高估狭窄程度6支,3D TRICKS MRA高估狭窄程度1支。以DSA为标准,2D TOF MRA诊断颈动脉狭窄的敏感度、特异度、诊断符合率分别为91.6%,85.7%,90.3%（K=0.737）;3D TRICKS MRA诊断颈动脉狭窄的敏感度、特异度、诊断符合率分别为97.9%,100%,98.4%（K=0.955）。两种方法对诊断颈动脉狭窄的敏感度、特异度和诊断符合率差异均具有统计学意义（P〈0.05）。结论：3D TRICKS MRA与DSA对评估颈动脉粥样硬化狭窄具有极好的一致性（K=0.955）,明显优于2D TOF MRA（K=0.737,P〈0.05）,是对颈动脉粥样硬化狭窄筛查、术前评估、术后随访的最佳检查方法,能基本替代DSA检查。     

不同方法MRA对脑动静脉畸形引流静脉显示价值的探讨

目的：探讨不同方法磁共振血流成像（MRA）对脑动静脉畸形（CAVM）引流静脉的显示价值。资料与方法：35例CAVM患者均接受了2D TOF MRA，18例同时接受了3D TOF、2D PC及3D PC MRA，10例还进行了3D CE MRA和DSA的检查。以DSA为标准，采用双盲法对CAVM的引流静脉经不同方法MRA检查后的显示情况进行回顾性分析，重点分析深、浅静脉的显示率及合并存在的引流静脉狭窄和扩张。结果：2D TOF可以较满意地显示深浅引流静脉，与DSA相比较，其符合率为90％，而对引流静脉的狭窄显示不清。3D TOF对引流静脉的显示符合率为50％，但可辨识静脉窦的血流方向。2D PC、3D PC在Venc=30cm/s或Venc=60cm/s时，其对引流静脉的显示符合率分别为87．5％和80％，PC法难以显示CAVMγ刀治疗后残存病灶的引流静脉。3D CE MRA可满意显示引流静脉的全程，静脉窦的狭窄以及其合并存在的动静脉瘘，显示符合率为100％。结论：2D TOF和3D CE MRA对CAVM引流静脉的显示有很高的符合率，应作为首选方法。     

MR快速多时相造影增强与时间飞跃血管成像在颈部血管疾病中诊断价值的对比研究

目的　对比研究磁共振时间飞跃血管成像 (timeofflightmagneticresonanceangiograhy,TOF MRA)与快速多时相造影增强成像 (contrastenhancemagneticresonanceangiography ,CE MRA)在颈部血管疾病中的诊断价值。方法　临床怀疑颈部血管疾病患者 12 6例 ,同时进行颈部TOF MRA和CE MRA检查 ,所有病例均行DSA或者手术 ,并以此为金标准对TOF MRA和CE MRA的图像质量 [信噪比(SNR)、对比噪声比 (CNR)、伪影 ]、颈总动脉分叉区狭窄诊断 (准确性、特异性、敏感性 )及其在血管畸形中的诊断价值进行对比研究。结果　经DSA或手术证实阳性病例共 89例 (动脉瘤 3例、动静脉畸形 2例、颈总动脉分叉区动脉硬化狭窄 84例 ,共 12 2处狭窄 ) ,CE MRA在颈总动脉分叉区的SNR、CNR分别为 2 0 94± 2 5 7、11 10± 3 84 ,TOF MRA为 12 5 5± 1 71、2 70± 0 74 ,二者差异具有显著性意义 (t值分别为 13 36和 11 5 0 ,P值均 <0 0 0 1)。 12 6例的TOF MRA均出现伪影 ,而CE MRA未发现伪影。CE MRA对颈总动脉分叉区狭窄诊断特异性为 99 2 3% ,TOF MRA为 2 1 5 4 % ,二者差异具有显著性意义 (χ2 =12 0 85 ,P <0 0 0 1) ;CE MRA对颈总动脉分叉区狭窄诊断的敏感度为 90 88% ,TOF MRA为93 4 4 % ,二者差异无显     

头颈部磁共振血管成像技术研究

目的探讨磁共振血管成像（MRA）在头颈部血管疾病的应用价值与限度。方法回顾性分析2010—2011年我院头颈部血管检查的病例,其中头部动脉671例,头部静脉7例,颈部动脉66例,进行三维时间飞越法磁共振血管成像（3D-TOF MRA）、二维时间飞越法磁共振血管成像（2D-TOF MRV）,部分病例做了心室血管造影（CTA）和数字减影血管造影（DSA）检查。磁共振场强为1.5 T,先行标准的磁共振成像（MRI）检查,然后行MRA;MRA采用3D TOF,部分患者还额外采用矢状和/或冠状预饱和技术,用最大密度投影（MIP）演算法处理资料。结果 MRA较好地显示了血管狭窄的部位、程度和范围,其中三维法较二维法显示病变为准确;可以认为,MRA是中风病因诊断和随访最好的无创性检查方法。结论 MRA具有安全、可靠和方便的优点,是头颈部血管疾病筛查的有力工具。     

多期相超短回波四维MRA在评估颅内血管狭窄中的应用价值

目的:探讨多期相超短回波四维磁共振血管成像(mUTE 4D MRA)在评估颅内血管狭窄中的应用价值.方法:前瞻性收集59例脑血管病患者的临床及影像资料,受试者均先行3D时间飞跃法MR血管成像(3D TOF MRA)和mUTE 4D MRA扫描,然后在同一天行CT血管成像(CTA)检查.由2位神经影像医师采用双盲法对血管...     

磁共振新技术在颈动脉狭窄诊断中的应用

目的研究增强磁共振血管成像（CE—MRA）技术的成像影响因素，评价MR扫描序列对颈动脉狭窄硬化斑块的应用价值，探讨颈动脉狭窄血流动力学变化与临床症状的联系。方法颈动脉狭窄34例，男22例，女12例。年龄36～78岁，平均56岁。病人首先经多普勒超声（DUS）检查，然后行MRA及CE-MRA。22例同时采用亮血（Bright—blood）、黑血（Black—blood）技术、3例行血流测量分析（Flow measurements）。10例于磁共振检查后1周内接受颈动脉狭窄内膜剥除术。扫描技术：（1）MRA及CE-MRA：MRA：二维时间飞跃法MRA（2D TOF MRA）；CE-MRA：快速梯度回波扫描技术，冠状位采集。最佳扫描延迟时间主要采用造影剂团注试验（test-bolus）法。3例采用时间分辨回波分享血管成像技术（TRATE）。（2）斑块检查序列：亮血与黑血技术及增强前后T1序列。（3）血流测量分析：横断位心电门控2D相位对比序列，Argus系统分析血流方向、流速。结果血管覆盖范围：34例CE-MRA，23例良好显示颈部血管起始段至入颅段。2D TOF法11例。动脉狭窄评估程度：10例手术患者中，CE-MRA正确诊断血管狭窄者9例，低估狭窄程度1例。2D TOF正确诊断血管狭窄程度6例，高估3例，低估1例。22例亮血、黑血技术结合CE—MRA清晰显示血管壁及动脉硬化斑块。颈动脉单独成像24例中，Test—bolus法团注造影剂最佳扫描延迟时间为峰值时间-1s，且监视层面定于主动脉弓者18例。4例眩晕患者，颈动脉狭窄侧后交通动脉（PCOA）显示2例；PCOA粗大1例。狭窄侧未显示PCOA，同侧大脑后动脉主干增粗1例。2例锁骨下动脉窃血综合征血流方向异常，1例无名静脉狭窄，同侧颈静脉血流方向异常。结论（1）CE—MRA能完整、全程显示颈部血管，准确诊断颈动脉、椎动脉狭窄。（2）Test-bolus法确定扫描延迟时间为峰值时间-1s，并将监视层面定于主动脉弓时，可保证造影剂在动脉内达到高峰浓度时采集K空间数据，获得颈动脉单独成像的最佳图像。（3）亮血、黑血技术结合CE-MRA有助于显示颈动脉狭窄硬化斑块。（4）分析、测量颈动脉狭窄的血流动力学变化能全面评价狭窄后血流改变与临床症状的联系。     

颅脑磁共振血管造影

目的：研究MRA的诊断价值。材料和方法：在0．5T超导磁共振成像机（VectraⅡ，GE）上，采用时间飞越法（TOF）和相位对比法（PC）作磁共振血管造影（MRA）。本文回顾分析了88例颅脑MRA的表现，68例采用PC法；5例采用TOF法；15例两者均采用。其中5例患者MRA检查后立即又做了DSA检查。结果：MRA可用于诊断各种颅内动脉瘤、血管畸形、血管狭窄或闭塞性病变，可以大致观察颅内肿瘤的血供及正常血管的移位或受侵情况。结论：本文比较了PC法和TOF法的优缺点，认为前者更能清晰完整显示颅内血管及其病变，MRA对于诊断各种血管性病变极有价值。     

肾动脉狭窄的三维增强磁共振血管成像诊断

目的:评价高分辨力三维增强磁共振血管成像术(3DCEMRA)对肾动脉狭窄的显示准确性。方法:对30例临床诊断或怀疑肾动脉狭窄患者进行高分辨力肾动脉3DCEMRA检查,分析所有患者的肾动脉和副肾动脉显示质量和病变显示情况,并与DSA做对照。结果:3DCEMRA显示了30例患者总共59支肾动脉主干(1例为单支移植肾动脉),显示率为100%。3DCEMRA显示4支副肾动脉,显示率100%。肾动脉段级分支的显示率为49%。所有病例在动脉显示区域内静脉均未显影或显影淡,对诊断不构成影响。DSA共显示59支肾动脉主干和4支副肾动脉(以63支计算),59支主干中2支闭塞,8支重度狭窄,11支中度狭窄,10支轻度狭窄,28支肾动脉主干和4支副肾动脉都正常。3DCEMRA除把2支轻度狭窄估为中度狭窄,1支中度狭窄估为重度狭窄外,其它结果都同DSA一致,故3DCEMRA显示肾动脉主干和副肾动脉狭窄程度超过50%的有血液动力学意义的明显狭窄的敏感性和特异性分别为100%和95%,阳性预测值为91%,阴性预测值为100%。结论:高分辨力肾动脉3DCEMRA能准确检出肾动脉主干和副肾动脉狭窄,并能较好判断其狭窄程度。     

Comparative assessment of helical CT-angiography, 2D TOF MR-angiography and 3D gadolinium enhanced MRA in aorto-iliac occlusive disease

PURPOSE: To compare helical CT-angiography (CTA) and two techniques of MR angiography (MRA) to conventional angiography in aorto-iliac occlusive disease. MATERIALS AND METHODS: The abdominal aorta and iliac arteries in 22 patients (4 for preoperative assessment of abdominal aortic aneurysm and 18 for peripheral vascular disease) were imaged using four techniques: digital subtraction angiography ("gold standard"), 2D TOF MR angiography, 3D Gd-enhanced MR angiography and helical CT angiography. Source (CTA and 2D TOF MRA) and MIPed images (after subtraction measures before and after gadolinium injection for 3D Gd-MRA) were reviewed. RESULTS: Sensitivity, specificity and accuracy for the detection of significant (>50%) stenosis and occlusion of aorto-iliac arteries were respectively: 38%, 89%, 77% for 2D TOF MRA; 75%, 71%, 72% for 3D Gd-MRA and 95%, 90%, 92% for CTA. Excluding the internal iliac arteries, results were 54%, 96%, 88% for 2D TOF MRA; 96%, 80%, 83% for 3D Gd-MRA and 92%, 93%, 95% for CTA. CONCLUSION: 3D Gd-MRA, a technique with potential for further improvement, is superior to 2D TOF MRA for detecting significant stenosis and occlusion of aorto-iliac arteries. Results at Gd-MRA are nearly similar to those at CTA (after excluding internal iliac arteries). Results at Gd-MRA are not affected by calcified plaque.     

Willis环磁共振血管成像与血管造影对比研究

目的：对比分析Ｗｉｌｌｉｓ动脉环的ＭＲＡ和ＣＡ表现,探讨ＴＯＦ法ＭＲＡ评价Ｗｉｌｌｉｓ环解剖与功能的价值。材料与方法：选择４３例颅脑血管和肿瘤疾病的ＴＯＦ法ＭＲＡ和ＣＡ资料。ＭＲＡ应用１．０Ｔ超导ＭＲ系统的３Ｄ或２ＤＦＩＳＰ序列扫描,原始血管图像用ＭＩＰ重建。ＣＡ西门子１２５０ｍＡＤＳＡ系统和岛津１０００ｍＡ造影造系统,采用Ｓｅｌｄｉｎｇｅｒ技术导管法股脑血管造（至秒摄取双侧颈动脉和一侧椎动脉造有     

Comparison of image quality, diagnostic confidence and interobserver variability in contrast enhanced MR angiography and 2D time of flight angiography in evaluation of carotid stenosis

The aim of this study was to compare image quality, level of diagnostic confidence and interobserver agreement in assessment of carotid stenosis with contrast enhanced MR angiography (CE MRA) in comparison with 2D time of flight MR angiography (2D TOF MRA). 60 carotid arteries in 30 patients were examined by three observers. Image quality and diagnostic confidence were assessed on the basis of a visual analogue scale. Interobserver variability was assessed with the help of intraclass correlation coefficient. Median values on the visual analogue scale for image quality and diagnostic confidence were higher for CE MRA compared with 2D TOF MRA for all three observers. Higher intraclass correlation values were recorded for interobserver variability for CE MRA compared with 2D TOF MRA both for visual estimation of carotid stenosis as well as for measurement of carotid stenosis on the basis of North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) criteria. CE MRA provides better image quality, higher level of diagnostic confidence and more interobserver agreement compared with 2D TOF MRA.     

Imaging of aortoiliac arterial disease. Duplex ultrasound and MR angiography versus digital subtraction angiography

Purpose: To evaluate and compare the diagnostic accuracy of duplex ultrasound (US) and MR angiography (MRA) at 1.0 T in aortoiliac arterial disease using digital subtraction angiography (DSA) as the reference standard. In addition, a comparison of the 2D time-of flight (TOF) and 3D contrast-enhanced MRA (CE MRA) techniques was performed.Material and Methods: Prospectively, 39 patients with symptoms of lower-extremity arterial occlusive disease were examined using US, TOF MRA, CE MRA and DSA. Significant lesions (stenosis ≥50%) and occlusions were evaluated blindly for each method.Results: For all segments, the sensitivity for US, TOF MRA and CE MRA with regard to significant lesions was 0.72, 0.81 and 0.81, respectively, and the specificity for each was 0.97, 0.91 and 0.92, respectively. For significant lesions above the inguinal ligament the corresponding sensitivity was 0.84, 0.89 and 0.94 and the specificity 0.93, 0.82 and 0.73, respectively. The specificity was higher when the two MRA methods were combined. TOF MRA overgraded 7 segments as occluded. In most cases, the length of the occlusions was correctly determined on CE MRA, overestimated on TOF MRA and uncertain on US.Conclusion: Neither US nor MRA were sufficiently accurate to fully replace angiography. MRA was preferable to US as a non-invasive test when vascular intervention was contemplated. Although CE MRA was superior to TOF MRA, the most accurate results were achieved when the two methods were combined.     

磁共振脑静脉系血管成像技术及其临床应用

目的探讨磁共振脑静脉系血管成像的技术方法和最佳扫描方案，评价磁共振静脉系血管成像技术(MR venography，MRV)对静脉系疾病的诊断价值及临床意义。方法采用二维时间飞跃法MR血管造影(2D-TOF-MRA)、二维相位对比血管造影(2D-PCA)和三维对比增强MR血管造影(3D-CE-MRA)3种血管成像技术分别对20例健康志愿者和20例临床或MRI疑有静脉系疾病的患者行MRV成像，并采用最大强度投影(MIP)、多平面或曲面重建(MPR)及数字减影MRA(DSMRA)技术对图像进行后处理，观察脑静脉系在MRV中的显示情况及脑静脉系疾病在MRV中表现形式，制定脑静脉系成像的最佳方案。结果本组经3D-CE-MRA静脉系成像诊断为13例颅内静脉窦血栓形成(CVST)及7例颅内肿瘤累及静脉系的阳性显示率为100％，均经临床治疗复诊及手术证实。2D-PCA及2D-TOF-MRA对细小引流静脉显示欠佳，且2D-TOF-MRA对复杂区域内静脉血管亦显示欠佳。结论3D-CE-MRA结合2D-PCA及2D-TOF-MRA静脉成像技术形成全脑静脉系成像，为脑静脉系的最佳成像方案，对临床术前评估和指导治疗有极其重要的意义。     

Contrast-enhanced MR angiography in patients with carotid artery stenosis: comparison of two different techniques with an unenhanced 2D time-of-flight sequence

Conventional time-of-flight (TOF) MR angiography (MRA) in carotid artery stenosis relies on flow-related enhancement to produce signal from vascular structures. Intravoxel phase dispersion, due to vortices, causes loss of signal and is the reason for the tendency to overestimate the degree of stenosis. In contrast-enhanced MRA, intravascular signal is mainly dependent on T1 shortening of the blood. We compared first-pass contrast-enhanced MRA (contrast-enhanced 3D gradient echo, ce3D GRE) and contrast-enhanced 2D TOF (ce2D TOF) sequences with an unenhanced 2D TOF in 13 patients with carotid artery stenosis, assessing delineation of the carotid bifurcation, enhancement of veins and grade of stenosis. The contrast-enhanced techniques produced more morphological detail, the ce3D GRE being superior to the ce2D TOF. Four carotid arteries were reclassified into lesser stenosis categories using the ce3D GRE technique. However, seven carotid arteries (27 %) were rated as nondiagnostic on the ce3D GRE, mainly due to masking of the carotid bifurcation by veins. The latter can be avoided by decreasing the acquisition time; on our 1.5-T system we could achieve a minimum time of 23 s per 3D GRE. Further reduction of acquisition time would be necessary to incorporate this method into clinical routine, requiring higher-performance gradients, which are not available in many UK hospitals. Received: 25 February 1999 Accepted: 29 July 1999