连续三维时飞法磁共振血管成像对脑动脉的显示能力评价

目的评价连续3D-TOF和高速度编码的三维相位对比法(Venc3D-PC)MRA对脑动脉的显示能力。方法前瞻性选取脑MRI表现正常且连续3D-TOF及高Venc3D-PC磁共振脑动脉成像表现正常者15例,用以评价2种MRA技术显示脑动脉的差异。回顾性选取进行脑动脉MRA及DSA2种检查者43例,以DSA为标准,取其中38侧表现正常者用以评价MRA显示脑动脉的能力。结果3D-TOF与高Venc3D-PC技术显示ACA、MCA或PCA的最大级数均无显著统计学差异,但前者的图像质量优于后者。MRA显示ACA、MCA和PCA的分支级数与DSA均有显著差异性。MRA对ACA和MCA的显示能力均较DSA减少1个级别,对PCA的显示能力差别不大。结论连续3D-TOFMRA对脑动脉的显示能力小于DSA,但已能满足大多数脑血管疾病的临床应用。     

64层螺旋CT脑动脉、混合脑动静脉和脑静脉血管成像─智能跟踪扫描减影技术

目的:探讨64层螺旋CT智能跟踪扫描减影技术在脑动脉、混合脑动静脉和脑静脉血管成像中的最佳启动扫描阈值和价值。方法:在我院行减影脑血管成像患者共105例,按启动扫描阈值大小分为三组,A组(90HU),共36例;B组(80HU),共34例;C组(70HU),共35例。对整个头部平扫、增强动脉早期和静脉早期扫描获得未减影数据,将动、静脉早期数据减去平扫数据获得减影动脉期、减影混合动静脉期数据,静脉早期数据减去动脉早期数据获得减影静脉期数据。采用VR、MIP重建减影血管图像。根据血管图像质量分为四级并分别记分。结果:(1)三组患者血管密度减影动脉期动脉较静脉显著高,减影混合动静脉期动脉和静脉均较高,减影静脉期静脉较动脉显著高。减影动脉期、减影混合动静脉期和减影静脉期血管密度组间比较相似,但减影动脉期C组动脉密度最低,减影混合动静脉期C组动脉密度最高、静脉密度最低,减影静脉期C组静脉密度最高。(2)减影图像与未减影图像相比去除了动脉、静脉相互的及颅骨的干扰,对脑动、静脉解剖结构显示清楚。①减影动脉期三组脑动脉图像质量均无0分,有诊断价值的病例均占100%,C组较A、B组图像质量稍好;②减影混合动静脉期三组混合脑动静脉图像质量均无0分,有诊断价值的病例均占100%,B、C组较A组图像质量好,B、C组图像质量相似;③减影静脉期A组脑静脉图像质量有诊断价值的病例占69.5%,B组脑静脉图像质量有诊断价值的病例占88.3%,C组脑静脉图像质量有诊断价值的病例占100%,C组图像质量明显好于A、B组。结论:64层螺旋CT智能跟踪扫描减影技术能分别显示脑动静脉、混合脑动静脉和脑静脉,以动脉期启动扫描阈值70HU图像质量最好,全部血管均有诊断价值,特别是对脑静脉的显示,值得临床推广应用。     

MRA与DSA在显示外伤性颈内动脉海绵窦瘘瘘口中的价值比较

目的 评价磁共振血管成像(MRA)与数字减影血管造影(DSA)在显示外伤性颈内动脉海绵窦瘘(TCCF)瘘口中的价值.资料与方法 回顾性分析11例TCCF患者的DSA及MRA影像学表现.结果 11例患者中,DSA能明确显示颈内动脉海绵窦瘘(CCF)瘘口者8例(8/11);11例(11/11)患者在MRA及其原始图像上均可直观明确显示瘘口.结论 MRA薄层无间隔扫描的原始图像及可多角度、多方位旋转观察的最大信号强度投影(MIP)图像可明确显示瘘口,优于DSA检查.     

自动移床3D CES MRA在下肢动脉检查中的初步应用

目的：探讨自动移床3维增强减影MR血管造影(3DCES MRA)在下肢动脉疾病检查中的应用价值。方法：16例临床怀疑下肢动脉性病变者进行了自动移床3D CES MRA认检查，原始图像经减影后作最大密度投影(MIP)重建。结果：所有病例的血管均显示满意，其中11例可见不同部位和分支动脉狭窄或闭塞，阳性诊断率为68．7％。结论：初步结果表明，自动移床3D CES MRA检查技术对下肢动脉病变有重要诊断价值。     

MRA在诊断颅内动脉瘤中的应用

目的：研究MRA诊断颅内动脉瘤的原理与方法，优势与不足以及临床价值。方法：选择经DSA证实为颅内动脉瘤的息者30例，行三维MRA及MRI检查，全部病例均经手术证实。结果：MRA对颅内动脉瘤的敏感性为90％，结合原始断层图像和MRI，敏感性则高达97％，较准确显示了3mm以上动脉瘤的形态、大小及与载瘤动脉的关系。对于检测血栓性动脉瘤MRA优于DSA影像。结论：MRA是一种无创伤的血管检查技术．可准确显示动脉瘤。对于Willis环区动脉瘤，MRA可取代常规血管造影。     

64排螺旋CT减影血管成像在头部烟雾病诊断中的应用

目的探讨64排螺旋CT减影血管成像技术在烟雾病诊断中的临床价值。方法回顾分析在我院行减影脑血管成像烟雾病患者,共18例。对整个头部平扫、增强动脉早期和静脉早期扫描获得未减影数据,将动脉早期数据减去平扫数据获得减影动脉期数据,静脉早期数据减去动脉早期数据获得减影静脉期数据。采用容积再现(VR)、最大密度投影(MIP)重建减影血管图像。结果减影图像去除了动脉、静脉相互的及颅骨的干扰,对脑动、静脉解剖结构显示清楚,特别是对烟雾病异常颈内动脉和脑底血管网显示。本组显示脑底异常血管网占100%;双侧颈内动脉狭窄占61%,左侧颈内动脉狭窄占17%,右侧颈内动脉狭窄占22%;双侧大脑中动脉狭窄占39%(其中1例左侧大脑中动脉闭塞),右侧大脑中动脉狭窄占17%;双侧大脑前动脉狭窄占39%(其中1例双侧大脑前动脉闭塞),无单侧大脑前动脉狭窄;合并脑动脉瘤占17%;全部脑静脉未见异常。结论 64排螺旋CT智能跟踪扫描减影技术能清楚分别显示脑动脉和脑静脉,在显示颅内动脉血管畸形时可排除脑静脉畸形,对颅内烟雾病分析评价有较大临床价值。     

64层螺旋CT分别脑动脉、脑动静脉和脑静脉成像—不同能量扫描比较研究

目的探讨64层螺旋CT同序列分别行脑动脉、脑动静脉、脑静脉的成像方法和最佳扫描能量（kV）。方法在我院行减影脑血管成像研究患者共220例,按扫描仟伏值大小随机分为三组,A组（120kV）,共59例;B组（100kV）,共85例;C组（80kV）,共76例。对整个头部平扫、动脉期和静脉期扫描（智能跟踪阈值70HU启动扫描）,将动、静脉期数据减去平扫数据获得减影动脉期、减影动静脉期数据,静脉期数据减去动脉期数据获得减影静脉期数据。采用容积再现（VR）、最大密度投影（MIP）重建减影血管图像。测量A、B、C组减影后血管密度和翼内肌SD噪声（客观噪声）,根据血管图像质量分为四级并分别记分。结果 1血管密度：A、B、C三组患者血管组内比较减影动脉期动脉较静脉密度显著高,差异有统计学意义（P〈0.05）,减影动静脉期动脉和静脉密度相似,差异无统计学意义（P〉0.05）,减影静脉期动脉较静脉密度显著低,差异有统计学意义（P〈0.05）。三组减影动脉期、减影动静脉期和减影静脉期血管密度组间比较随能量降低密度升高,差异有统计学意义（P〈0.05）;2图像质量：A、B、C三组减影脑动脉全部有诊断价值,组间两两比较差异有统计学意义（P〈0.05）;三组减影动静脉全部有诊断价值,Ⅰ级图像以C组减影脑动静脉图像质量最高,BC组间两两比较差异无统计学意义（P〉0.05）,AC和BC组间两两比较差异有统计学意义（P〈0.05）;三组减影脑静脉少数无诊断意义,Ⅰ级图像以B组最高,AC组间两两比较差异无统计学意义（P〉0.05）,AB和BC组间两两比较差异有统计学意义（P〈0.05）;3辐射剂量和噪声：三组辐射剂量随能量的降低而明显下降,三组噪声随能量的降低而明显增加（P〈0.05）。结论 64层螺旋CT同序列能分别脑动脉、脑动静脉和脑静脉成像,脑动脉、脑动静脉全部有诊断价值,仅     

MRA对脑动静脉畸形的再评价

目的　总结脑动静脉畸形 (AVM )的MR征象 ,评价磁共振血管成像 (MRA)显示AVM各征象的准确性。方法　MRA和DSA诊断脑AVM 3 6例 ,从AVM的大小、输入动脉、输出静脉等方面对比分析其MRI、MRA及DSA表现 ,分析病灶大小与其动静脉支数的关系。结果　AVM发生部位遍布脑组织各个结构。其MRI征象主要有 :病灶部位呈蜂窝状线样流空低信号 ,病灶周围增粗血管的流空 ,病灶周围的脑萎缩和梗塞等。MRA征象包括畸形血管团以 2～ 5cm为多 ,占 5 5 .6% ;输入动脉来源于该部位原有供血动脉增粗而成 ;输出静脉以病灶为中心向四周引流入相应的静脉 (窦 ) ;血管支数与病灶大小呈正相关 ,但分布较分散。MRA与DSA对比显示 ,MRA显示的病灶明显大于DSA(t=2 .65 ,P =0 .0 3 ) ,输出静脉支数多于DSA(t =2 .5 3 ,P =0 .0 4)。结论　MRA能够显示脑AVM的所有征象 ,在诊断上不次于甚至优于DSA。其MRI表现在脑AVM的检查和诊断中均有重要作用 ,应更加重视     

Willis环的3D MRA、3D FSPGR和DSA对比研究

目的　以DSA结果为标准 ,比较 3DTOF、3DPC、3DFSPGR序列及联合运用时对Willis环各组成血管的显示能力。方法　同时进行增强MRA和全脑DSA检查的病人 5 5例 ,对所得的 3DTOF源图像、3DTOFMIP、3DPCMIP、3DFSPGR图像上显示的Willis环组成血管进行判定和联合分析 ,并与DSA结果比较 ,计算各种MRA图像对Willis环组成血管中ACOA、PCOA、P1、A1显示的敏感性、特异性及阴性、阳性预测值。结果　各种评定方法对A1、P1评定的敏感性在 94.12 %以上 ,特异性和阳性预测值均达 10 0 %。对于ACOA、PCOA ,3DTOF源图像、3DFSPGR图像和联合分析结果的敏感性、特异性、阳性预测值和阴性预测值均近似 ;敏感性及阴性预测值均明显高于 3DTOF和 3DPCMIP ,阳性预测值均低于MIP图像。结论　 3DPCMIP ,3DTOF源图像和 /或 3DFSPGR联合可能不仅提高Willis环显示的特异性 ,还可提高其显示的敏感性。     

平扫心电门控时间分辨4D稳态自由进动(SSFP)MR血管成像(MRA)评估颅内侧支血流:与数字减影血管造影比较

目的评价平扫时间分辨4DSSFPMRA序列动态显示颅内侧支血管的能力。方法本研究包括22例脑供血动脉狭窄-阻塞的病人[平均年龄(59.0±11.8)岁]。颅内动脉4DSSFPMRA影像采集采用1.5TMRI,时间相位15,时间分辨率115ms。所有病人均接受了脑血管数字减影血管造影     

Utility of contrast-enhanced 3D turbo-flash MR angiography in evaluating the intracranial venous system

The objective of this study was to compare the effectiveness of contrast-enhanced 3D turbo-flash and 2D time-of-flight (TOF) magnetic resonance angiography (MRA) sequences in the visualization and evaluation of the intracranial venous system. A prospective study was carried out on 41 patients referred to our Magnetic Resonance Imaging (MRI) unit with clinical findings suggestive of dural sinus thrombosis. Contrast-enhanced 3D turbo-flash and 2D TOF MRA sequences were performed, and the dural sinuses and cerebral veins were classified into five grades according to the quality of visualization and presence of thrombosis. We found the dural sinuses and cerebral veins to be normal in all sequences in 31 patients. Thrombosis of dural sinuses was detected in ten patients, with four of these ten cases found only in the contrast-enhanced 3D turbo-flash sequence. In general, complete visualization of cerebral veins and dural sinuses was significantly better accomplished with contrast-enhanced 3D turbo-flash MRA than with 2D TOF in either coronal or sagittal/oblique planes. Although 2D TOF MRA may be superior in detecting chronic dural sinus thrombosis, contrast-enhanced 3D turbo-flash MRA sequences may offer advantages for the early diagnosis and management of acute and subacute dural sinus thrombosis.     

2D time-of-flight MR angiography using concatenated saturation bands for determining direction of flow in the intracranial vessels

We prospectively studied 15 patients to assess 2D time-of-flight (TOF) magnetic resonance angiography (MRA) with concatenated saturation bands for determining the direction of intracranial blood flow. This MRA sequence was compared to T2-weighted spin-echo MRI, 3D-TOF MRA, and intra-arterial angiography (IAA) as regards demonstration of vessels and determination of the direction of flow in the circle of Willis and its branches. The 2D-TOF MRA sequence demonstrated flow in 98.5 % vessel segments identified on IAA, 3D-TOF demonstrating 92 % and spin-echo images 77 %. The direction of flow shown on the 2D-TOF sequence was correct in 94 % when compared to conventional angiography, the remaining six segments not demonstrating flow. In ten patients, the flow abnormalities demonstrated by this MRA technique provided clinical information similar to that of conventional angiography in nine, but it was incomplete in three, and misleading in one. Slow retrograde flow in ophthalmic artery collaterals and differentiation of arteries and veins presented some problems. 2D-TOF MRA with concatenated saturation bands provides flow direction information using widely available, easily applicable TOF techniques, and can be a useful adjunct to MRI and MRA if information on flow direction is needed. Received: 18 October 1995 Accepted: 16 August 1996     

Contrast-enhanced MR 3D angiography in the assessment of brain AVMs

Background and purposeDigital subtraction angiography (DSA) is the current reference standard for the diagnosis, assessment, and management of brain arteriovenous malformations (AVMs). The purpose of this study was to compare the diagnostic utility of three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) and contrast-enhanced 3D MRA in patients with intracranial arteriovenous malformations (AVMs) in different sizes and locations. The AVM diagnosis was proved via DSA and almost half of the patients had also hematoma.Materials and methodsTwo radiologists, experienced on neurovascular imaging and independent from each other, retrospectively reviewed two MRA techniques and DSA with regard to the assessment of feeding arteries, AVM nidus, and venous drainage patterns on 20 patients with 23 examinations by scoring system. Disagreements were resolved by consensus.ResultsAn excellent agreement between contrast-enhanced MRA and DSA was found in order to assess the numbers of arterial feeders and draining veins (Spearman r = 0.913, P < 0.001). The average scores in contrast-enhanced MRA for feeders, nidi, and drainers were respectively 2.26, 2.69, and 2.48, while in TOF-MRA they are 1.96, 1.35, and 0.89, respectively.ConclusionCompared to TOF-MRA, 3D contrast-enhanced MRA is useful for visualization by subtraction technique of malformation components presented by hematoma or by haem product. On the other hand, for the cases presented by slow or complex flow that is especially in around or nidi or around the venous portion is also advantageous because of the independence from flow-related enhancement. Therapeutic effects were clearly demonstrated in three follow-up patients. A major limitation of this technique is the low spatial resolution. Since there is such a limitation, arterial feeder of a case with micro-AVM is not detected by contrast-enhanced MRA and nidus for the same case was observed retrospectively. In this respect, we believe that 3D contrast-enhanced MRA is a less invasive and inexpensive angiographic tool, but not a safe substitute for DSA. Yet, it can be a benefıcıal supplement to DSA in patients with cerebral AVMs at both initial diagnosis and at follow-up processes after therapy.     

Cerebral arteriovenous malformations: morphologic evaluation by ultrashort 3D gadolinium-enhanced MR angiography

The purpose of this study was to evaluate the usefulness of a new ultrashort contrast-enhanced (CE) MR angiography (MRA) for the morphologic evaluation of cerebral arteriovenous malformations (AVMs). The method was compared with conventional X-ray digital subtraction angiography (DSA) and time-of-flight (TOF) MRA in 22 patients to assess the angioarchitecture of the malformations which is essential for treatment planning and follow-up. Two experienced MR readers independently evaluated both techniques with regard to the assessment of feeding arteries, AVM nidus, and venous drainage patterns. Contrast-enhanced MRA was able to detect all AVMs seen on DSA, whereas the TOF MRA failed in 1 patient with a very small AVM. In the assessment of the different vessel components of the AVM there was no difference for the detection and delineation of feeding arteries and the AVM. The venous drainage patterns could always be clearly delineated in the CE MRA, whereas TOF MRA could demonstrate the exact venous drainage in only 9 patients. Contrast-enhanced MRA was found to be superior to conventional TOF MRA in the assessment of the angioarchitecture of cerebral AVMs especially regarding the assessment of the venous drainage patterns. The superiority is supported by the improved vessel-to-background contrast and contrast-to-noise ratios. The major limitations of this new technique consist of a low spatial resolution at the used time resolution which can be improved by further sequence modifications. Contrast-enhanced MRA is thus an important additional imaging technique for treatment planning and follow-up of AVMs. Electronic Publication     

Contrast-enhanced MR 3D angiography in the assessment of brain AVMs

BACKGROUND AND PURPOSE: Digital subtraction angiography (DSA) is the current reference standard for the diagnosis, assessment, and management of brain arteriovenous malformations (AVMs). The purpose of this study was to compare the diagnostic utility of three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) and contrast-enhanced 3D MRA in patients with intracranial arteriovenous malformations (AVMs) in different sizes and locations. The AVM diagnosis was proved via DSA and almost half of the patients had also hematoma. MATERIALS AND METHODS: Two radiologists, experienced on neurovascular imaging and independent from each other, retrospectively reviewed two MRA techniques and DSA with regard to the assessment of feeding arteries, AVM nidus, and venous drainage patterns on 20 patients with 23 examinations by scoring system. Disagreements were resolved by consensus. RESULTS: An excellent agreement between contrast-enhanced MRA and DSA was found in order to assess the numbers of arterial feeders and draining veins (Spearman r=0.913, P<0.001). The average scores in contrast-enhanced MRA for feeders, nidi, and drainers were respectively 2.26, 2.69, and 2.48, while in TOF-MRA they are 1.96, 1.35, and 0.89, respectively. CONCLUSION: Compared to TOF-MRA, 3D contrast-enhanced MRA is useful for visualization by subtraction technique of malformation components presented by hematoma or by haem product. On the other hand, for the cases presented by slow or complex flow that is especially in around or nidi or around the venous portion is also advantageous because of the independence from flow-related enhancement. Therapeutic effects were clearly demonstrated in three follow-up patients. A major limitation of this technique is the low spatial resolution. Since there is such a limitation, arterial feeder of a case with micro-AVM is not detected by contrast-enhanced MRA and nidus for the same case was observed retrospectively. In this respect, we believe that 3D contrast-enhanced MRA is a less invasive and inexpensive angiographic tool, but not a safe substitute for DSA. Yet, it can be a beneficial supplement to DSA in patients with cerebral AVMs at both initial diagnosis and at follow-up processes after therapy.     

下肢深静脉血栓形成MR检查的临床价值

目的探讨下肢深静脉血栓形成磁共振血管成像（MRA）和下肢深静脉血栓磁共振直接成像（MRDTI）的临床价值。资料与方法对25例临床确诊为下肢深静脉血栓形成的患者进行MRA和MRDTI检查．MRA采用二维时间飞越法（2DTOF）；MRDTI选用SET1WI、FSET2WI、FAST（fourier acquired steady state，FAST）序列。其中23例行数字减影血管造影（DSA）检查，MRA与DSA进行对照分析。结果下肢深静脉血栓形成的MRA表现有：静脉充盈缺损（14例）、静脉闭塞和中断（8例）、静脉再通（3例）、侧支循环形成（25例）。以DSA为诊断标准，MRA诊断符合率为95．65％。下肢深静脉血栓形成MRDTI表现为：急性血栓（19例），血栓在SET1WI、FSET2WI和FAST序列上多为等信号或高信号，信号多不均匀，6例可见血管周围水肿；慢性血栓（6例），血栓在SET1WI、FSET2WI和FAST序列上多均为低或等信号。结论2DTOFMRA结合多种序列MRDTI的表现，诊断下肢深静脉血栓更准确,并可以为判断血栓新旧提供依据。     

Prominent laterality of the posterior cerebral artery at three-dimensional time-of-flight MR angiography in M1-segment middle cerebral artery occlusion

BACKGROUND AND PURPOSE: Three-dimensional time-of-flight MR angiography (3D TOF MRA) often discloses prominent posterior cerebral artery (PCA) laterality in the setting of M1-segment middle cerebral artery (MCA) occlusion. We sought to analyze the implications of prominent PCA laterality at 3D TOF MRA. METHODS: We retrospectively reviewed 3D TOF MRA and digital subtraction angiography (DSA) findings in 25 patients (12 male, 13 female; mean age, 68.8 years [age range, 29-94 years]) with M1-segment occlusion. The observable laterality of the PCA, determined on the basis of 3D TOF MRA findings, was scored according to distal signal extent and compared with findings of collateral flow from the ipsilateral PCA via the leptomeningeal anastomosis (LMA) at DSA. Frequency of PCA laterality at 3D TOF MRA in patients and that in 56 healthy control subjects was also compared. RESULTS: The positive predictive value of PCA laterality for the existence of collateral flow was 99.9% and the negative predictive value 30.7%. The distal extent of ipsilateral PCA signal at 3D TOF MRA positively correlated with the grade of collateral flow from the PCA via the LMA (r = 0.802; P <.01). PCA laterality was significantly less common in control subjects (P <.01). CONCLUSION: Prominent PCA laterality at 3D TOF MRA in patients with M1-segment occlusion represents the existence of collateral flow from the PCA via the LMA.     

蛛网膜下腔出血患者的MRA和DSA的对照研究

目的：研究ＭＲ血管造影（ＭＲＡ）在蛛网膜下腔出血（ＳＡＨ）患者病因诊断中的应用准确性和可靠性。材料和方法：回顾性分析３３例ＳＡＨ患者的ＭＲＡ资料，并与ＤＳＡ作了对比分析，ＭＲＡ采用三维时间流逝（３Ｄ－ＴＯＦ）法。结果：ＭＲＡ上显示了２６例血管病变中的２２例，包括１５个动脉瘤中的１３个，８例动静脉畸形中的６例和３例血管狭窄闭塞性病变。１个完全血栓形成的右颈内动脉瘤ＭＲＡ上未显示。但常规ＭＲＩ和ＭＲＡ原始图像上显示，ＭＲＡ结合ＭＲＩ和ＭＲＡ原始图像可以对９１％的患者做出正确诊断和评价，动脉瘤和周围血管的关系及ＡＶＭ的供血动脉和畸形结节能在ＭＲＡ上被准确评价。结论：作为一种非损伤性的血管成像方法，ＭＲＡ具有安全、可靠和方便的优点，可以做为常规用于ＳＡＨ患者的筛选检查。     

MRA与CDS对头颈部动脉狭窄或闭塞的对照研究

目的：探讨ＴＯＦ法ＭＲ血管成像（ＭＲＡ）所箜呈闭塞与彩色多普勒超声（ＣＤＳ）所探查的血流状态的关系,为提高ＭＲＡ诊断狭窄或闭塞的准确性提供依据。材料与方法：地３２例脑缺血性疾病患者（１３５支动脉）进行ＭＲＡ和ＣＤＳ的双盲法对照研究,同时以ＤＳＡ为对照标准,对８例患者进行ＭＲＡ、ＣＤＳ的对照分析。结果：在ＭＲＡ诊断的动脉狭窄中,ＣＤＳ表现为高速血流的占５２．５％,低束 流者占４７．５％;ＴＯＦ法ＭＲ     

Three-dimensional time-of-flight MR angiography in the evaluation of cerebral aneurysms

We review our preliminary experience with the use of three-dimensional (3D) time-of-flight (TOF) magnetic resonance (MR) angiography (MRA) in the assessment of intra- and extracranial aneurysms. Six patients were examined: Five had intracranial aneurysms and one had a cervical carotid pseudoaneurysm. A 3D rephased gradient recalled echo pulse sequence and maximum intensity projection (MIP) reconstruction algorithm were used. Magnetic resonance angiography, spin echo MR, and conventional angiography were retrospectively reviewed with specific regard to individual vessel visualization, aneurysm depiction, and presence of artifact related to acquisition techniques or MIP reconstruction. All aneurysms were detected on MRA, and anatomical correlation with conventional angiography was excellent. Significant problems included loss of visualization of small vessels, intraluminal signal loss in large vessels, subacute thrombus simulating flow on MIP reconstructions, and limited projections obtainable with MIP techniques. Adequate MRA assessment of aneurysms can be obtained using a combination of T1-weighted spin echo images and 3D TOF MRA. Review of all components of the MRA is required. MRA may be useful in screening asymptomatic patients for intracranial aneurysms as well as in the follow-up of patients treated with balloon occlusion.