MR血管成像诊断脊髓动静脉畸形的价值

目的 探讨磁共振血管成像(包括快速3D增强MRA技术和常规MRA)在脊髓动静脉畸形的诊断价值.方法 回顾分析10例脊髓动静脉畸形MRA资料,均由选择性脊髓血管造影确诊,全部病例均使用3D增强MRA技术(CE-MRA),头颈部另外还使用常规MRA(3D-TOF MRA).结果 髓内动静脉畸形3例,AVM血管巢的MRA表现为血管粗细不一,扭曲成团,并显示1条或多条供血动脉及增粗的引流静脉.髓外硬膜内动静脉畸形5例,其中3例为AVM,MRA显示有血管巢、供血动脉及引流静脉;2例为AVF,MRA可以显示供血动脉及引流静脉,并可推断瘘口的位置.硬脊膜动静脉瘘2例,MRA只表现为髓周血管扩张.结论 MRA不仅可以对脊髓动静脉畸形作定性诊断,而且还可以显示病灶的内部结构,已成为无创性诊断脊髓血管畸形的理想方法.     

磁共振成像和磁共振血管造影对脑动静脉畸形的诊断评价

目的 探讨MRI和MRA,尤其后者对脑动静脉畸形（AVM）诊断价值和限度。材料与方法,对16例AVM者行MRI和MRA检查并与DSA进行对照研究,分别观察供血动脉,血管巢和引流静脉情况。结果 与DSA对照,显示供血动脉,MRA与其无显著差异（P＞0．05）,MRI有其极显著差异（P＜0．001）;血管巢大小,MRI,MRA与其均无显著差异（P＞0．05）,引流静脉,MRI与其有显著差异（P＜0．001）。结论 MRA与MRI联合应用可准确显示供血动脉,血管巢和部分引流静脉,是一种评价AVM血管内治疗,手术切除或立体定向放疗及效果观察的有效无创性检查方法。随着MRA新技术的不断开发,完善,将部分取代有创性DSA检查。     

脑静脉畸形的MRI表现及其诊断价值

目的 探讨脑静脉畸形的MRI表现,评价各成像序列的诊断价值。资料与方法 搜集经临床手术证实的脑静脉畸形8例进行回顾性分析,所有患者均进行了常规MRI平扫及3D-MOTSA MRA检查。6例行Gd-DTPA增强T1WI,其中3例行3D-MOTSA增强MRA检查。结果 小脑4例,额叶、顶叶、枕叶共4例。5例MRI平扫引流静脉为长T1短T2流空信号,3例呈长T1低信号、长T2高信号。扩张的髓静脉为网状及条状长T1低信号、长T2高信号,增强扫描呈“海蛇头”样改变,即多条髓静脉呈辐射状汇入粗大的引流静脉。3D-MOTSA MRA检查显示部分引流静脉,髓静脉显示较少。3D-MOTSA增强MRA检查引流静脉全程显示,髓静脉显示数目多。结论 MRI能明确诊断脑静脉畸形的合并症,弥补脑血管造影的不足,3D-MOTSA增强MRA检查可取代脑血管造影。     

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     

3D-TOF MRA及SWI对脑血管畸形的对照研究

目的:通过分析脑动静脉畸形和海绵状血管瘤的的3D-TOF MRA及SWI磁共振表现,探讨3D-TOF MRA及SWI对脑血管畸形的诊断价值。方法:对我院收治的44例血管畸形进行高场磁共振成像,并加扫3D-TOF MRA及SWI序列,其中26例海绵状血管瘤、18例动静脉畸形。通过分析SW I和3D-TOF-MRA技术对脑血管畸形的显示情况,比较二者对脑血管畸形的检出率以及细微特征的鉴别能力等。结果:3D-TOF MRA可以清晰显示动静脉畸形的部位、大小、输入动脉的来源、输出静脉的去向等;海绵状血管瘤MRA检查均未见异常供血动脉,病灶内无异常流空信号。SWI可清晰显示海绵状血管瘤,病灶的数目及范围较常规序列增大;SWI只能显示动静脉畸形迂曲的小静脉,但不能直观显示畸形血管团的全貌及输入动脉等粗大血管的情况。结论:3D-TOF MRA技术对于AVM之类高流速低阻力的血管畸形的显示具有独特的价值,而SWI技术则对于海绵状血管瘤等小血管或低流速的血管畸形的显示具有明显的优势。     

CT与MRI用于脑静脉扩张畸形诊断的比较研究

目的:探讨脑静脉畸形的CT、MRI表现,评价CT、MRI在诊断颅内静脉畸形中的价值与局限.方法:搜集经手术证实或DSA明确诊断的脑静脉畸形15例,均行常规CT﹑MRI平扫及增强扫描,部分病例行3D-MOTSA CE MRA检查.结果:CT平扫可显示部分扩张的引流静脉及少数明显扩张的髓静脉血管,MRI平扫可显示大部分扩张的引流静脉及部分扩张的髓静脉,CT增强扫描可显示全部引流静脉及大部分扩张的髓静脉,MRI增强扫描可显示全部的引流静脉及扩张的髓静脉,CTA及3D-MOTSA CE MRI可显示引流静脉全程及髓静脉丛.结论:CT和MTR增强扫描是诊断脑静脉畸形的有效方法,CTA及3D-MOTSA CE MRA扫描可更加精确的显示扩张的髓静脉分支及引流静脉走行.MRI平扫对脑静脉畸形的筛选价值优于CT.     

脑动静脉畸形的增强MRA

3D-TOF MRA能明确瘤巢及供血动脉,但由于逐渐饱和效应的影响,小动脉及引流静脉显示不佳。CE MRA不依赖于流动效应。而和 Gd-DTPA导致的 T_1 时间缩短有关。Gd-DTPA能够抵消 3D-TOFMRA的逐渐饱和效应,本文分析了12例AVM增强 3D-TOF MRA表现。并和平扫MRA作了比较,结果表明:增强MRA对瘤巢、供血动脉及引流静脉的显示均有不同程度的提高。     

磁共振血管成像对烟雾病诊断价值的探讨

目的:探讨MRA和MRI对烟雾病的诊断价值。方法:回顾性分析18例烟雾病MRA和DSA表现,18例中5例同时行DSA,采用2.0T超导高磁场MR扫描仪,MRA采用3D-TOF或3D-PC法。DSA采用GE Advantx心血管造影系统。结果:MRA显示狭窄或闭塞的血管,表现为多支、双侧受累。MRI平扫表现脑基底部狭窄、闭塞血管的流空效应减弱甚至消失,侧支循环血管形成所致的点状、条状迂曲低信号影。8例颅内可见血肿。结论:MRA作为一种无创伤的血管成像技术,能准确诊断moyamoya病可以与DSA媲美,结合MRI平扫可同时显示脑组织病变。     

螺旋CT血管造影在诊断脑动静脉畸形中的应用

目的探讨脑动静脉畸形(AVM)CT血管造影(CTA)的价值.材料与方法19例脑AVM病例行CTA检查,其中MRA、DSA检查各5例、8例.12例手术证实,7例保守治疗.CTA、MRA经工作站处理,获得三维血管图像;DSA通过股动脉插管技术,获得减影后血管图像.结果CTA能显示AVM的病变形态及准确部位,有效显示供养动脉、引流静脉及血管巢.但供养动脉显示不及MRA,引流静脉的显示较MRA为佳.结论CTA诊断脑AVM的图像质量、病变显示接近MRA、DSA,对制定治疗方案、指导手术和预后有重要意义.     

磁敏感加权成像在脑静脉畸形诊断中的应用

目的：探讨磁敏感加权成像（SWI）在脑静脉畸形诊断中的价值。方法：回顾性分析19例脑静脉畸形的常规MRI及SWI表现。结果：19例常规MRI均可显示引流静脉,其中9例可显示髓静脉汇入引流静脉;19例磁敏感加权成像均可清晰显示引流静脉及髓静脉,呈现特征性的＂海蛇头＂或＂蜈蚣＂征。结论：SWI较常规MRI更能清晰和精确地显示脑静脉畸形的影像特征,可作为脑静脉畸形诊断常规序列的重要补充。     

Cerebral vascular malformations: applications of magentic resonance imaging to differential diagnosis

Summary Twelve patients with cerebral vascular malformations (5 cavernous angiomas, 1 thrombosed arteriovenous malformation, and 6 venous angiomas) were studied with magnetic resonance (MR) imaging. All lesions were clearly depicted. Characteristic MR findings were obtained mainly on T2-weighted images: a markedly low intensity area was always seen. The margins of arteriovenous malformation (AVM) and venous angioma were irregular while those of cavernous angioma were smooth in all planes on T2-weighted images. Gradient-echo (GrE) pulse sequences were more sensitive than T2-weighted spin echo (SE) in lesion detection. MR imaging could play an important role in the differential diagnosis of cerebral vascular malformations.     

脑血管畸形的MRI及MRA诊断

目的：研究脑动静脉畸形与海绵状血管瘤的ＭＲＩ及ＭＲＡ特征，评价不同的成像方法对脑血管畸形的诊断价值。材料与方法：对２１例脑动静脉畸形及６例海绵状血管瘤分别作了常规ＭＲ成像及ＭＲ血管成像，ＭＲＩ采用ＳＥＴ１和Ｔｕｒｂｏ ＳＥ Ｔ２加权序列，ＭＲＡ采用２Ｄ－ＦＬＡＳＨ及３Ｄ－ＦＩＳＰ序列，６例海绵状血管瘤ＭＲＡ仅使用２Ｄ－ＦＬＡＳＨ序列。所有成像以环形激化头线圈在１．０Ｔ ＭＲ仪上完成。结果：Ｔ１及Ｔ     

Abnormal venous drainage in periventricular leukomalacia

Age-matched six control subjects and 14 selected paediatric patients with periventricular leukomalacia were prospectively studied by MR imaging, and MR angiography. MR angiograms were acquired utilizing either the three-dimensional phase-contrast (3D-PC) or the two-dimensional time-of-flight (2D-TOF) techniques, or both, in an axial slab centred to the centrum semiovale. Abnormal draining veins (slightly enlarged and long vessels with abnormal courses) were found in eight of 14 patients (57%). In five of these eight patients (62.5%) abnormal vessels were identified on conventional MR imaging (spin-echo, T2-weighted and flow sensitive images), while the 3D-PC or 2D-TOF angiograms demonstrated the abnormal vessels in all the patients (100%). Usually there was a single abnormal vessel at the region of interest. These vessels should not be misinterpreted as arteriovenous malformations or venous malformations.     

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     

MR digital subtraction angiography of cerebral arteriovenous malformations

BACKGROUND AND PURPOSE: Although phase-contrast MR angiography provides some information regarding hemodynamics of cerebral arteriovenous malformations (AVMs), most conventional MR angiographic techniques have not been helpful in this respect. We attempted to determine the value of MR digital subtraction angiography (DSA) in assessing AVM hemodynamics. METHODS: We developed an MR DSA technique by combining rapid thick-section T1-weighted imaging with a bolus injection of contrast material. The temporal resolution was 0.56 to 0.61 seconds per scan. MR DSA images obtained from 14 patients with AVMs were reviewed. Anatomic depiction of each component of the AVM was rated using a four-point grading scale (excellent = 3, good = 2, fair = 1, poor = 0) to compare conventional vs MR angiograms. RESULTS: We were able to obtain serial images in which passage of contrast material was evident within the AVM, although the sequence we used allowed images to be obtained in only one projection. The average score for feeders, nidi, and drainers was 1.6, 2.4, and 2.3, respectively, with an overall average of 2.1. CONCLUSION: The spatial resolution of our technique may fall below the level needed for identification of small vascular components of an AVM. Additionally, the limited slab may restrict application of the technique to assessment of large or very small AVMs. MR DSA, however, can show the hemodynamics of AVMs and may serve as a supplement to conventional MR imaging in the diagnosis of cerebral AVMs.     

Three-dimensional dynamic MR digital subtraction angiography using sensitivity encoding for the evaluation of intracranial arteriovenous malformations: a preliminary study

BACKGROUND AND PURPOSE: Our aim was to develop 3D dynamic MR digital subtraction angiography with high temporal resolution without sacrificing spatial resolution by using sensitivity encoding for the evaluation of cerebral arteriovenous malformations. METHODS: Nineteen patients with 19 angiographically proven arteriovenous malformations (16 supratentorial and 3 infratentorial) were assessed by conventional catheter angiography and 3D dynamic MR digital subtraction angiography. A 3D contrast-enhanced gradient-echo sequence with sensitivity encoding based on a parallel imaging technique was performed and acquired 20 dynamic images, repeated 18 times every 1.7 seconds. Three-dimensional dynamic MR digital subtraction angiograms were analyzed independently by two radiologists in a blinded fashion with regard to arteriovenous malformation nidus and venous drainage. Conventional catheter angiography was used as reference. RESULTS: All MR imaging examinations were assessable. Interobserver agreement was excellent for the detection of nidus and for the evaluation of nidus size (kappa = 1 and 0.875, respectively) but moderate for the visualization of the venous drainage (kappa = 0.56). All nidi detected on conventional catheter angiography were clearly depicted on 3D dynamic MR digital subtraction angiography. The evaluation of the size of the nidus by both techniques was similar. On 3D dynamic MR angiograms, veins were correctly analyzed in 17 of 19 arteriovenous malformations. CONCLUSION: Our preliminary study demonstrates that 3D dynamic MR digital subtraction angiography using sensitivity encoding with a high spatial resolution is appropriate for the assessment of arteriovenous malformations.     

Hochaufgelöste MR-Venographie zerebraler arteriovenöser Malformationen

PURPOSE: The purpose of this study was to evaluate the diagnostic potential of a high resolution MR venography technique in patients with cerebral arteriovenous malformations (AVM). A high-resolution 3D gradient echo sequence was used with a long echo time TE to obtain venous information down to sub-pixel sized vessel diameters of several hundred microns. The method is based on the paramagnetic property of deoxyhemoglobin and the resulting developing phase difference between veins and brain parenchyma at long echo times which leads to signal cancellation. The reconstructed venograms were compared with TOF-MR angiography using qualitative and quantitative criteria with the conventional DSA serving as the reference gold standard. METHODS: In 17 patients with angiographically proven cerebral AVM the method indicates its potential in clinical applications. Venography was able to detect all AVM whereas TOF-MRA failed in three patients. In the delineation of venous drainage patterns MR venography was superior to TOF-MRA, however, as expected the method detected only about half of the main feeding arteries. Due to susceptibility artifacts at air/tissue boundaries or interference with paramagnetic hemosiderin, MR venography was limited with respect to the delineation of the exact nidus sizes and shapes in ten patients with AVM located close to the skull base or in patients having suffered from previous bleeding. RESULTS: Although the visualization of draining veins represents an important prerequisite in the surgical and radiosurgical treatment planning of cerebral AVM, there exist limitations of the technique in regions where strong induced static field inhomogeneities are present. CONCLUSIONS: Due to its high sensitivity the method may be of special importance in the early detection and assessment of small AVM which are difficult to diagnose with other MR methods.     

Size determination of supratentorial arteriovenous malformations by MR,CT and angio

Summary Twenty patients with high-flow supratentorial arteriovenous malformations (AVMs) were studied by magnetic resonance imaging (MR), computed tomography (CT), and selective cerebral angiography. The size of the malformation measured on MR was found, in general, to be smaller than the size determined from angiographic films. This discrepancy increased as the size of the AVM increased. AVM size on CT and angiography was found to be essentially equivalent. The reason for these differences between MR and CT or angiography was the ability to separate out the draining veins by MR, whereas this was difficult on projection films and contrast enhanced CT. Calcification was more easily detected by CT than by MR. MR better detected hemorrhage, which could be mistaken for old infarction on CT. Foci of cystic change within the nidus of the AVM were equally evident on MR and CT. Due to its sensitivity in discriminating between AVM nidus and adjacent draining veins and MR's ability to show the AVM in three planes, MR appeared to be more accurate in defining the AVM nidus than either CT or cerebral angiography. Such accurate delineation is crucial in patients prior to stereotactic radiosurgery.     

De novo cerebral arteriovenous malformation: case report and literature review

We describe a rare case of a de novo cerebral arteriovenous malformation (AVM) in a 9-year-old girl. MR imaging at 6 years of age demonstrated band heterotopia. Follow-up MR imaging 3 years later demonstrated a new 3.5-cm AVM in the left parietol-occipital region, confirmed by conventional angiography. This report, along with limited previous reports, suggests that AVMs can be acquired lesions and that AVM development is a dynamic process extending into the postnatal period.