Magnetic resonance angiography compared to intra-arterial digital subtraction angiography in patients with subarachnoid haemorrhage

Summary In order to evaluate the sensitivity and specificity of magnetic resonance angiography (MRA) in spontaneous subarachnoid haemorrhage, 14 patients with recent haemorrhage verified by CT or lumbar puncture were investigated with both selective intra-arterial digital subtraction angiography (IA-DSA) and MRA by two independent teams, each having the same preangiographic information. The results were compared with each other and whenever possible (all positive cases except one) with those of surgical intervention. Seven patients were identified by MRA and IA-DSA as having a single aneurysm on the circle of Willis, 1 an aneurysm of the posterior inferior cerebellar artery 1 an aneurysm of the internal carotid artery (siphon) and 2 patients with two aneurysms on the circle of Willis. MRA and IA-DSA both failed to demonstrate aneurysms in 2 cases. Three patients had negative results on both methods and no surgical intervention was attempted. The aneurysms ranged from 0.3 to 1.5 cm in size. In most cases there was agreement between MRA and DSA, leading us to believe that, if the proper protocols are followed, MRA is a powerful alternative to other established methods in the detection of intracranial aneurysms. At this stage it will not replace IA-DSA prior to surgery, but the ability to obtain various projections using 3D MRA may improve surgical planning.     

Magnetic resonance imaging and angiography in hemifacial spasm

Summary We used magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) to investigate 14 patients with unilateral hemifacial spasm (HS) and 20 controls. The relationship of the seventh and eighth cranial nerves to adjacent vessels was best visualized on the contiguous flow sensitive 3D-FISP images. Reconstruction of projectional MRA was helpful to assess the complex architecture of the vertebrobasilar system. Neurovascular contact in the facial nerve root exit zone was present in 4 of 20 controls and in 12 of 14 patients, in whom it predicted the affected side. These results support previous findings of surgical and electrophysiological investigations that local irriation of the facial nerve is the most possible explanation for HS. MRI and MRA provide vascular and brain tissue diagnosis in a single non-invasive examination and should be recommended as primary neuroradiological procedure in HS.     

Magnetic resonance imaging and angiography of the brain in embolic left atrial myxoma

Summary A case of left atrial myxoma presenting exclusively with neurological symptoms, studied with magnetic resonance imaging (MRI) combined with cerebral angiography and computed tomography (CT) is reported. Typical angiographic findings suggested the diagnosis of myxoma. MRI showed multiple ischemic lesions disseminated throughout the entire brain, some of which had been clinically asymptomatic. Because of its sensitivity in identifying small cerebral infarcts, MRI should prove in the future to be a first-choice technique in the evaluation of the presence of and extent of cerebral involvement in embolic left atrial myxoma.     

烟雾病的MRI、MRA诊断价值

 目的探讨MRI、MRA对烟雾病(Moyamoya病)的诊断价值.方法对11例Moyamoya病患者行MRI和MRA检查,MRI包括横轴位和矢状位T1WI、T2WI、FLAIR;MRA采用3D TOF法,3例行增强MRA.结果MRI表现为:(1)Moyamoya血管:双侧3例,单侧8例;(2)脑梗死和脑软化灶11例;(3)局部脑萎缩3例.MRA表现为3例双侧颈内动脉狭窄,双侧大脑中、前动脉闭塞,大脑后动脉形成异常血管网;6例右侧颈内动脉、大脑中动脉狭窄;2例左侧颈内动脉、大脑中动脉狭窄.结论MRI能良好的显示脑内病变,MRA能较完整的显示异常血管,MRI与MRA相结合可作为烟雾病诊断的首选检查方法.     

Magnetic resonance angiography of intracranial aneurysms: comparison with intra-arterial digital subtraction angiography

Summary Magnetic resonance angiography (MRA) with flow rephased gradient-echo sequences is a new non-invasive method for vascular imaging. We compared MRA and intra-arterial digital subtraction angiography in 18 patients with intracranial aneurysms to test whether MRA presently provides an alternative to cerebral angiography for the diagnosis of these anomalies. MRA showed 19 of the 22 aneurysms detected (86.4%). However, problems, especially with turbulent or slow flow, resulted in 6 studies (27.3%) with limited and 2 with questionable demonstration of an aneurysm, and 1 false negative study. At present, MRA is definitely inferior to angiography for the demonstration of intracranial aneurysms, due to its lower resolution and other limitations.     

Magnetic resonance tomographic angiography in the investigation of hemifacial spasm

Magnetic resonance angiography (MRA), combined with submillimeter magnetic resonance tomographic angiographic sections (MRTA) showed vascular compression of the 7th cranial nerve or its root exit zone (REZ) in the brain stem in 24 of 37 patients (64.86%) with hemifacial spasm. MRA alone was positive for REZ compression in only 19 (51.4%) cases, while conventional MRI was even less revealing, only 10 (27%) cases being positive.     

Magnetic resonance angiography in meningovascular syphilis

Meningovascular neurosyphilis (MN) is an unusual cause of stroke in young adults. The clinical manifestations include prodromal symptoms weeks or months before definitive stroke. The diagnosis is based on clinical findings and examination of the serum and cerebrospinal fluid. We report a case of MN with basilar artery irregularities demonstrated by magnetic resonance angiography.     

Magnetic resonance angiography and selective angiography following extra-intracranial bypass operations

Magnetic resonance angiography (MRA) was compared with conventional angiography in 14 patients following extra-intracranial arterial anastomosis. In 13 patients the bypass was shown by MRA and confirmed by conventional angiography. In five of these, the anastomosed vessels, in particular the superficial temporal artery, was of the same calibre or smaller than the same vessels on the contralateral, healthy side. In one patient no anastomosis could be shown by MRA, and occlusion of the bypass was confirmed by conventional angiography. Absence of dilatation of the anastomotic vessels may indicate insufficient bypass function due to stenosis or an incorrect indication for surgery.     

颅内动脉溶栓联合机械碎栓治疗急性脑梗死

目的探讨动脉溶栓联合机械碎栓治疗急性脑梗死的可行性和安全性。方法通过对9例急性脑梗死患者实施动脉内尿激酶溶栓联合机械性碎栓介入治疗(其中大脑前动脉A1段栓塞1例、大脑中动脉M1段栓塞6例、颈内动脉C1段狭窄1例、颈内动脉主干栓塞1例;起病距介入治疗时间3 h内2例,3～6 h 5例,>24 h 2例。结果7例6 h以内急性脑梗死患者主要栓塞血管得到100%开通,2例大于24 h患者症状得到改善(颈内动脉C1段狭窄1例、颈内动脉主干栓塞1例)。结论超选择局域性动脉内尿激酶溶栓联合机械碎栓治疗6 h以内急性脑梗死,能使闭塞的血管尽快开通,是一种安全有效的介入治疗术式。     

Magnetic resonance angiography of cerebral developmental venous anomalies: its role in differential diagnosis

Summary CT, MRI and contrast angiography of 20 patients with 21 developmental venous anomalies (DVAs), so-called venous angiomas, were compared with magnetic resonance angiography employing a two-dimensional time-of-flight technique (2D-MRA). MRA was diagnostic in 17 DVAs, when both the primary 2D slices and the maximum-intensity-projection images were read. Contrast angiography still provides the best visualization of both DVA components: dilated medullary veins and transcerebral draining vein; however, it is an invasive procedure and delivers no information about brain parenchyma. We regard MRI as necessary in cases with a suspected DVA because of the high rate of association with cavernomas: 33% in this study. Acute neurological symptoms were caused by haemorrhage from an associated cavernoma and not from the DVA in 4 such cases. Thus MRA combined with MRI obviates angiography in most cases and offers a noninvasive diagnostic strategy adequate for DVAs.     

Magnetic resonance angiography (MRA) in renally impaired patients: when and how

Magnetic resonance angiography (MRA) and NSF in renally impaired patients have a close relationship due to the frequent coincidence of vascular and renal pathologies, the relatively large amount of contrast media applied and the delayed excretion. The date of the first NSF cases described in literature falls into the development of multi-stationary MRA—an investigation that requested multiple bolus injections or one large bolus of the contrast agent. It is therefore easily understood that NSF was regarded initially as possible complication of MRA.

A review on the history of MRA is presented and various techniques for MRA are described. While many neuroradiological indications can be solved by native MRA, most angiographic indications throughout the body rely on the application of intravenous contrast agents.

The paper discusses options for alternative methods in vascular imaging and offers guidelines for patients with renal impairment. NSF must always be balanced versus the outcome of an investigation, respectively versus the outcome of a denied MRA. Moreover, in patients with chronic kidney disease (CKD) and a proper justification for a vascular investigation, neither CT angiography nor DSA should replace MRA. Restrictions in contrast media dose for CKD patients are mandatory and obviously reduce the risk of NSF. Gadolinium-based contrast agents with lower stability are now contraindicated in patients with reduced renal function. The role of blood pool agents is under evaluation.

Since the awareness of the new disease grew over the last year, radiologists were able to reduce the number of newly diagnosed NSF cases by more careful consideration of contrast application and agent in renally impaired patients, which gives hope that NSF can be avoided by respecting some easy rules.     

脑灌注MRI与脑血管造影在评价脑缺血病变中的价值

目的 通过对脑缺血性疾病患者的脑动脉血管造影和脑灌注ＭＲＩ对照，评价脑缺血性疾病中侧支循环建立情况，并试图鉴别脑缺血性病变的性质。     

Magnetic resonance imaging of dorsolateral medullary infarction in Wallenberg's syndrome

In a case of Wallenberg's syndrome, infarction of the dorsolateral medulla was shown to be caused by thrombosis of the left vertebral artery, as demonstrated by T1-weighted magnetic resonance imaging, magnetic resonance angiography and conventional angiography.     

Magnetic resonance angiography (MRA) of the circle of Willis: a prospective comparison with conventional angiography in 54 subjects

We prospectively correlated the findings of magnetic resonance angiography (MRA) with those of transfemoral four-vessel angiography in 54 patients to investigate the direction of flow within the circle of Willis. Our primary goal was to assess the direction of flow using the size of the vessel and signal intensity, without saturation techniques. Analysis of the circle of Willis, especially the communicating arteries, was performed double-blind by two groups of two radiologists. Three types of arteries were identified: high flow or cross-cerebral circulation, patent and nonvisualised arteries. Cerebral angiography was the standard for comparison between the two methods. MRA did not reveal any arteries invisible on angiography, thus providing a specificity of 100%. The sensitivity of MRA was 89.2% for the anterior and 81.3% for the posterior communicating arteries, and 100% for the anterior, middle and posterior cerebral arteries. MRA was shown to be a useful technique for the assessment of patency of the circle of Willis.     

Magnetic resonance angiography of supratentorial tumours: comparison with selective digital subtraction angiography

We compared magnetic resonance angiography (MRA) and intra-arterial digital subtraction angiography (IADSA) in the study of brain tumours and assessed the utility of gadolinium-enhanced MRA. We studied 17 patients with supratentorial brain tumors. The entire brain was imaged with multiple overlapping thin volume acquisitions. After IV injection of gadolinium-DTPA, a single thick-slab MRA acquisition was performed. Standard three-dimensional (3D-TOF) acquisitions (in six patients) and 3D-TOF with magnetization transfer prepulse and tilted optimisation nonsaturing radiofrequency excitation pulses (in 11 patients) were used. Displacement of the anterior cerebral artery, main stem and insular branches of the middle cerebral artery was seen well on unenhanced and contrast-enhanced MRA. Displacement of the lenticulostriate and anterior choroidal arteries was seen only once, after Gadolinium. Tumour encasement of the middle cerebral artery was demonstrated in one patient. Tumour vessels were seen in 2 of 8 cases before and 3 of 8 after gadolinium; Tumour hypervascularity was seen only after gadolinium, in 3 of 8 cases. Study of the veins was possible only on gadolinium-enhanced MRA. Displacement of the venous angle was seen in 4 of 7 patients in the frontal, and in all of 8 patients on the lateral projections. Early venous drainage was not seen. Patency of the dural venous sinuses was demonstrated in all patients, but in one neoplastic occlusion of a cortical vein was recognised.     

Magnetic resonance angiography of extracranial carotid and vertebral arteries,including their origins: comparison with digital subtraction angiography

Summary Although carotid bifurcation stenoses are not the only lesions of the extracranial cerebral arteries, magnetic resonance angiographic (MRA) studies to date have concentrated on the carotid bifurcation. We compared digital subtraction angiography of the extracranial portions of the cerebral arteries with MRA using an ordinary body coil, the time-of-flight method, and multiple transverse slabs which covered the arteries down to the aortic arch. Twenty-two patients (15 with arteriosclerotic diseases, 4 with aortitis, and 3 with tumours) had MRA using a 1.5 T magnet system with a three-dimensional fast imaging with steady state precession (FISP) technique. Thirty-nine carotid and 39 vertebral arteries were assessed by three radiologists with regard to stenoses or occlusions, graded as normal, mild (<30%), moderate (30–60%) or severe (>60%) stenosis, or occluded. Grading corresponded well in 81%; stenoses appeared more marked on MRA in 14% and were seen less clearly on MRA in 5%. When 26 carotid bifurcations were assessed separately, grading corresponded well in 95%. MRA is the only method which can display the whole course of the extracranial carotid and vertebral arteries non-invasively and satisfactorily.     

Magnetic resonance tomographic angiography: diagnostic value in trigeminal neuralgia

A combination of MRI, MR angiography and MR tomographic angiography (MRTA) was used to study the relationship to the root exit zone of the trigeminal nerve to surrounding vascular structures in seven patients with trigeminal neuralgia (TN) and ten patients with no evidence at a lesion in this region. MRTA is the technique for showing the relationship between vessels, cranial nerves and brain stem. MRTA clearly demonstrated the presence of a vessel at the root exit zone of the trigeminal nerve in all patients with TN. In the ten other patients, examination of 20 trigeminal nerves revealed that only one nerve (5%) was in contact with a vessel at the root exit zone. This study supports vascular compression of trigeminal nerves as a cause of TN, and demonstrates the value of MRTA as noninvasive technique for demonstrating compression.     

造影增强MR血管成像对急性缺血性中风患者血管状况的评估价值

目的:探讨CE-MRA在急性缺血性中风患者血管状况评估中的可行性。方法:27例大脑中动脉供血区急性缺血性中风患者在发病后6h内进行了TOF-MRA和CE-MRA检查,根据随访结果,对TOF-MRA和CE-MRA在急性缺血性中风患者血管状况的评估价值进行了对比分析。结果:①在27例患者中,有11例患者在TOF-MRA上表现为大脑中动脉完全闭塞而在CE-MRA上仍可见残余血流,随访结果与CE-MRA结果一致;②CE-MRA的扫描时间明显短于TOF-MRA;③CE-MRA可以在不增加扫描时间的情况下对颈部动脉和颅内动脉同时成像。结论:CE-MRA能够及时、准确地对急性缺血性中风患者血管状况进行评估,优于常规的TOF-MRA,由于急性缺血性中风患者需要紧急处理,在应用MR评估血管状况时CE-MRA应为首选。     

糖尿病人脑血管病发生时的磁共振血管成像特征

目的：对43例Ⅱ塑糖尿病患者头颅MRA及临床进行分析，以探讨Ⅱ型糖尿病患者脑血管改变与病程、临床及预后的关系。方法：全部病例均行头颅MRI和MRA检查(Elseirlt2．0)，采用自旋回波序列，T1、T2加权轴位、矢状位和冠状位平扫及加认检查。结果：43例中发现加认异常27例，主要改变：①颅内动脉主干的单发和多发性狭窄；②血管主干的完全性闭塞；③颅内特定部位的血管稀疏区和血管分支的减少；④慢性闭塞后的侧枝血管增加；⑤动脉粥样硬化造成的血管僵直样改变；⑥血管限局性膨大样改变。随病程年限增加加认异常率亦有上升，但临床症候的轻重与MRA有一定关系。结论：糖尿病患者魔用MRA检查有助于对脑血管受损程度进行评估，对预防脑卒中有重要价值。