Topographic anatomy of paraclinoid carotid artery aneurysms: usefulness of MR angiographic source images

We evaluated the usefulness of magnetic resonance angiography (MRA) for showing the topography of paraclinoid carotid artery aneurysms in 27 patients with 30 paraclinoid aneurysms undergoing conventional angiography, three-dimensional time-of-flight MRA and surgery. The anatomy shown on the axial MRA source images was consistent with that found at surgery. The neck of the aneurysm could always be identified on the source images, while it could not be analysed exactly on conventional angiography in 3 cases (10 %). The optic nerves, including those displaced by the aneurysm, were recognised in all patients. The anterior clinoid process was shown as a low-intensity rim or area contiguous with the cortical bone. The source images were of great value in understanding the topography of paraclinoid carotid artery aneurysms. Received: 11 April 1996 Accepted: 12 August 1996     

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。     

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.     

脑动脉瘤的MR血管造影与IA—DSA的对照研究

对经手术证实的２０例脑动脉瘤的ＭＲＡ和ＩＡ－ＤＳＡ的影像进行了对照分析研究，经ＭＲＡ检出１９例（９５％）动脉瘤，１０ｍｍ以下的动脉瘤９例，最小的为４ｍｍ，与ＤＳＡ检出率（１９／２０）相仿。ＭＲＡ的定位符合率为８４％，低于ＤＳＡ（９５％）。１３／１９例（６８％）在ＭＲＡ图象上能显示动脉瘤的瘤颈。作者认为ＭＲＡ是一种新的非侵入性的血管影像方法，可作为脑动脉瘤高危病例的筛选检查，随着ＭＲＡ技术的进一步完善，ＭＲＡ有望在神经外科领域替代部分侵入性血管造影检查。     

Three-dimensional display of the orifice of intracranial aneurysms: a new potential application for magnetic resonance angiography

Our aim was to demonstrate the orifice of intracranial aneurysms by magnetic resonance angiography (MRA). The aneurysmal orifice is that part of its lumen that communicates with the parent vessel. We studied 12 patients with 17 intracranial aneurysms using three-dimensional display (3DD) MRA; 15 of the aneurysms had previously been shown by digital subtraction angiography (DSA). The overall image quality of 3DD MRA was excellent in 10 patients. The orifice was clearly demonstrated in 13 aneurysms (76%) providing unique information about its size, shape and orientation. The orifice of 2 aneurysms (12%) was not demonstrated. Two aneurysms (12%) were not detected on MRA. Although 3DD MRA has limitations this study suggests that it can accurately define the orifice of aneurysms and could be used to provide information crucial for endovascular treatment.     

Intracranial aneurysms: evaluation by MR angiography

The purpose of this study was to compare the accuracy of a volume gradient-echo MR angiography (MRA) technique with that of intraarterial digital subtraction angiography (IA DSA) in the identification of intracranial aneurysms. The intracranial vasculature was examined in 47 patients by MRA and compared with IA DSA findings in 19 of these patients who had saccular or giant intracranial aneurysms. The remaining 28 patients, in whom no aneurysm was found, served as a control group. MRA was performed with the use of a velocity-compensated gradient-echo sequence (TR = 40-50/TE = 7-15) with a 15 degrees flip angle. The sensitivity and specificity were calculated for the evaluation of the cine 3D reconstructions (cine MRA) only, cine MRA + inspection of the individual partitions, and cine MRA + individual partitions + spin-echo studies. Of 21 aneurysms, of which three were missed in two patients, the sensitivity varied from 67% for cine MRA only to 86% for the cine MRA + partitions + spin-echo studies; of the 19 patients, among whom it was assumed that the diagnosis of any one aneurysm in a patient would lead to angiography and detection of additional aneurysms, the sensitivity varied from 73% for the cine MRA only to 95% for the cine MRA + partitions + spin-echo studies. The results of this study suggest that MRA can define the circle of Willis sufficiently to allow detection of intracranial aneurysms as small as 3-4 mm. MRA holds promise as a truly noninvasive screening examination of intracranial vasculature in patients at risk for aneurysms.     

Intracranial aneurysms: evaluation by MR angiography

The purpose of this study was to compare the accuracy of a volume gradient-echo MR angiography (MRA) technique with that of intraarterial digital subtraction angiography (IA DSA) in the identification of intracranial aneurysms. The intracranial vasculature was examined in 47 patients by MRA and compared with IA DSA findings in 19 of these patients who had saccular or giant intracranial aneurysms. The remaining 28 patients, in whom no aneurysm was found, served as a control group. MRA was performed with the use of a velocity-compensated gradient-echo sequence (TR = 40-50/TE = 7-15) with a 15 degree flip angle. The sensitivity and specificity were calculated for the evaluation of the cine 3D reconstructions (cine MRA) only, cine MRA + inspection of the individual partitions, and cine MRA + individual partitions + spin-echo studies. Of 21 aneurysms, of which three were missed in two patients, the sensitivity varied from 67% for cine MRA only to 86% for the cine MRA + partitions + spin-echo studies; of the 19 patients, among whom it was assumed that the diagnosis of any one aneurysm in a patient would lead to angiography and detection of additional aneurysms, the sensitivity varied from 73% for the cine MRA only to 95% for the cine MRA + partitions + spin-echo studies. The results of this study suggest that MRA can define the circle of Willis sufficiently to allow detection of intracranial aneurysms as small as 3-4 mm. MRA holds promise as a truly noninvasive screening examination of intracranial vasculature in patients at risk for aneurysms.     

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.     

Preliminary evaluation of volume-rendered three-dimensional display of time-of-flight MR angiography in the diagnosis of intracranial aneurysms

We assessed the value of the volume-rendering method of displaying images of three-dimensional (3D) time-of-flight MR angiography (MRA) in the diagnosis of intracranial aneurysms. We obtained three-dimensional volume-rendered MRA from 21 patients with intracranial aneurysms. The images were evaluated in comparison with maximum-intensity-projection images (in 21 patients), conventional angiograms (in 21 ) and CT angiography (in nine). In 17 patients, 3D volume-rendered images were thought to show morphological features most clearly. They were superior to the other methods for demonstrating the precise location of the aneurysm in three patients and in showing the shape of the bleb in another three. 3D volume-rendered MRA can be effectively added to conventional imaging techniques for diagnosis of intracranial aneurysms. Received: 12 October 2000 Accepted: 12 December 2000     

Time-of-Flight Magnetic Resonance Angiography for Follow-Up of Coil Embolization with Enterprise Stent for Intracranial Aneurysm: Usefulness of Source Images

Objective

The aim of this study was to determine the interobserver and intermodality agreement in the interpretation of time-of-flight (TOF) MR angiography (MRA) for the follow-up of coiled intracranial aneurysms with the Enterprise stent.

Materials and Methods

Two experienced neurointerventionists independently reviewed the follow-up MRA studies of 40 consecutive patients with 44 coiled aneurysms. All aneurysms were treated with assistance from the Enterprise stent and the radiologic follow-up intervals were greater than 6 months after the endovascular therapy. Digital subtraction angiography (DSA) served as the reference standard. The degree of aneurysm occlusion was determined by an evaluation of the maximal intensity projection (MIP) and source images (SI) of the TOF MRA. The capability of the TOF MRA to depict the residual flow within the coiled aneurysms and the stented parent arteries was compared with that of the DSA.

Results

DSA showed stable occlusions in 25 aneurysms, minor recanalization in 8, and major recanalization in 11. Comparisons between the TOF MRA and conventional angiography showed that the MIP plus SI had almost perfect agreement (κ = 0.892, range 0.767 to 1.000) and had better agreement than with the MIP images only (κ = 0.598, range 0.370 to 0.826). In-stent stenosis of more than 33% was observed in 5 cases. Both MIP and SI of the MRA showed poor depiction of in-stent stenosis compared with the DSA.

Conclusion

TOF MRA seemed to be reliable in screening for aneurysm recurrence after coil embolization with Enterprise stent assistance, especially in the evaluation of the SI, in addition to MIP images in the TOF MRA.     

Magnetic resonance angiography in the management of aneurysmal subarachnoid haemorrhage: a study of 51 cases

We report preliminary experience with the use of magnetic resonance angiography (MRA) in the assessment of intracranial aneurysms. The aims of the study were to confirm that aneurysms could be detected and to assess the quality of the images with a view to early surgery if clinically indicated. We studied 51 patients with recent spontaneous subarachnoid haemorrhage with MRA, using a three-dimensional time-of-flight technique. The results of MRA were subsequently confirmed on intra-arterial digital subtraction angiography (IA-DSA) for anatomical correlation, and were considered satisfactory in 38 patients (74.5 %). In 20 patients early surgical obliteration of their aneurysm was possible on the MRA results without recourse to IA-DSA. A total of 37 aneurysms were identified in 32 patients, while the remaining 6 patients did not have an aneurysm. MRA was misinterpreted in 4 patients (7.9 %), and in 9 other patients (17.6 %) MRA was unsatisfactory due to movement artefacts. Received: 1 September 1994 Accepted: 12 May 1995     

Three-dimensional time-of-flight MR angiography for evaluation of intracranial aneurysms after endosaccular packing with Guglielmi detachable coils: comparison with 3D digital subtraction angiography

The sensitivities and specificities of three-dimensional time-of-flight MR angiography (3D-TOF MRA) and 3D digital subtraction angiography (3D-DSA) were compared for evaluation of cerebral aneurysms after endosaccular packing with Guglielmi detachable coils (GDCs). Thirty-three patients with 33 aneurysms were included in this prospective study. 3D-TOF MRA and 3D-DSA were performed in the same week on all patients. Maximal intensity projection (MIP) and 3D reconstructed MRA images were compared with 3D-DSA images. The diameters of residual/recurrent aneurysms detected on 3D-DSA were calculated on a workstation. In 3 (9%) of 33 aneurysms, 3D-TOF MRA did not provide reliable information due to significant susceptibility artifacts on MRA. The sensitivity and specificity rates of MRA were 72.7 and 90.9%, respectively, for the diagnosis of residual/recurrent aneurysm. The diameters of residual/recurrent aneurysms that could not be detected by MRA were significantly smaller than those of detected aneurysms (mean 1.1 vs mean 2.3 mm). In one aneurysm of the anterior communicating artery (ACoA), the relationship between the residual aneurysm and the ACoA was more evident on MRA than DSA images. MRA can detect the recurrent/residual lumen of aneurysms treated with GDCs of up to at least 1.8 mm in diameter. 3D-TOF MRA is useful for follow-up of intracranial aneurysms treated with GDCs, and could partly replace DSA.     

三维动态增强MR血管造影对颅内动脉瘤的诊断价值

目的 评价三维动态增强磁共振血管造影(3D DCE-MRA)在颅内动脉瘤诊断中的价值。方法 对54例高度怀疑有颅内动脉瘤的病人行3D DCE-MRA检查，随后行DSA造影及可行的血管内栓塞治疗。3D DCE-MRA用超快速三维梯度回波序列(3D FISP)(钆喷替酸葡甲胺0．2mmol／kg,1次扫描时间10s)，工作站上三维重建，比较3D DCE-MRA及常规DSA在显示动脉瘤、瘤颈及与载瘤动脉关系上的优劣，及对血管内栓塞治疗的价值。结果 39例脑动脉瘤患者共45个动脉瘤，3D DCE-MRA对动脉瘤的敏感度为96％，特异度73％，准确度90％。3D DCE-MRA对动脉瘤细节及瘤颈的显示明显优于常规DSA，尤其是颈内动脉海绵窦部及椎动脉近小脑后下动脉的动脉瘤，可指导DSA显示动脉瘤方向及预先制定治疗方案。但对周边部及动脉分岔处小动脉瘤的诊断应谨慎。结论3D DCE-MRA能无创有效地诊断颅内动脉瘤，所提供的三维信息对治疗方案的制定具有极大帮助。当诊断有怀疑时，应结合DSA检查。     

Diagnostic accuracy of 3D time-of-flight MR angiography compared with digital subtraction angiography for follow-up of coiled intracranial aneurysms: influence of aneurysm size

BACKGROUND AND PURPOSE: 3D time-of-flight MR angiography (3D TOF MRA) may be used as noninvasive alternative to digital subtraction angiography (DSA) for the follow-up of patients with intracranial aneurysms treated with Guglielmi detachable coils (GDCs). We aimed to determine the influence of aneurysm size and location on diagnostic accuracy of 3D TOF MRA for follow-up of intracranial aneurysms treated with GDCs. MATERIALS AND METHODS: Two hundred and one 3D TOF MRAs in 127 consecutive patients with 136 aneurysms were compared with DSA as standard of reference. Sensitivity and specificity of 3D TOF MRA for detection of residual or reperfusion of the aneurysms was calculated with regard to aneurysm size and location. RESULTS: Overall sensitivity and specificity of MRA was 88.5% and 92.9%, respectively. Sensitivity was lower for aneurysms 相似文献   

Magnetic resonance angiography in the selection of patients suitable for neurosurgical intervention of ruptured intracranial aneurysms

This study was aimed at establishing whether magnetic resonance angiography (MRA) can be applied to planning and performing surgery on ruptured intracranial aneurysms, especially in the early phase, without recourse to intra-arterial digital subtraction angiography (IA-DSA). From February 1998 to August 2001, in all patients presenting with a subarachnoid hemorrhage, MRA was performed first. A three-dimensional time-of-flight MRA protocol with T2-weighted coronal and axial images was used. If MRA demonstrated an aneurysm, surgery was undertaken. IA-DSA was limited to patients with negative or inconclusive MRA findings. We compared MRA images with operative findings in positive patients and with IA-DSA in negatives. IA-DSA was considered the gold standard when MRA findings were inconclusive. In this study, 205 consecutive patients (mean age 52.7 years, 69% women) were included. In 133 patients (64.9%) MRA demonstrated an aneurysm, directly followed by neurosurgical intervention. In 33 patients (16.1%) MRA findings were categorized as inconclusive. In 39 patients (19.0%) MRA results were negative. No false-negative ruptured aneurysms were selected by MRA. In only one patient surgical intervention was performed based on false-positive MRA findings. MRA can replace IA-DSA as a first diagnostic modality in the selection of patients suitable for surgical treatment of ruptured intracranial aneurysms.This paper was presented in whole at the following meetings: ECR Vienna March 2003; RSNA Chicago December 2002; and CIRSE Lucerne October 2002     

颅内动脉瘤 3D DCE-MRA与DSA对照研究

目的 探讨三维动态增强MR血管造影(3D DCE-MRA)在颅内动脉瘤诊断中的价值. 资料与方法 对39例临床拟诊动脉瘤和常规MRA可疑动脉瘤的患者行3D DCE-MRA,随后行DSA,比较两种方法 对颅内动脉瘤的显示情况. 结果 34例动脉瘤患者中共有动脉瘤41个,3D DCE-MRA对动脉瘤诊断的敏感性为95%,特异性为80%,准确性为85%,3D DCE-MRA与DSA比较,差异无统计学意义(P>0.05). 结论 3D DCE-MRA是一项无创、安全、简便和可靠的诊断颅内动脉瘤的方法,对于颅内较大血管的动脉瘤的显示,可以取代DSA.     

3D TOF turbo MR angiography for intracranial arteries: phantom and clinical studies

This work investigated whether turbo magnetic resonance angiography (MRA) can replace conventional MRA in screening examination of intracranial arteries. A phantom was used to evaluate the effect of the zero-filling interpolation (ZFI) technique on spatial resolution and partial volume effect. Thirty-one consecutive patients underwent both turbo MRA with a slice thickness of 0.7 mm (data were measured as 1.33 mm sections) and conventional MRA with 1.0 mm sections. In the phantom studies, ZFI did not improve the spatial resolution, but the partial volume effect was somewhat reduced. In the clinical evaluation, turbo MRA showed better signal-to-noise and contrast-to-noise ratios of the intracranial major vessels than conventional MRA. The lesions included cerebral aneurysms less than 3 mm in diameter, occlusive vascular disease, arteriovenous malformations, and arteriovenous fistulas. These were all depicted on both turbo MRA and conventional MRA. Turbo MRA is a useful screening procedure because of its capability of delineating lesions in approximately half the usual imaging time. J. Magn. Reson. Imaging 1999;10:939-944.     

The non-invasive detection of intracranial aneurysms: are neuroradiologists any better than other observers?

Can non-neuroradiologists detect intracranial aneurysms as well as neuroradiologists, using CT and MR angiography? Sixty patients undergoing intra-arterial digital subtraction angiography (IADSA) to detect aneurysms also underwent computed tomographic angiography (CTA) and time-of-flight magnetic resonance angiography (MRA). Consensus review of IADSA by two neuroradiologists was the reference standard. Two neuroradiologists, a neurosurgeon, a neuroradiographer and a general radiologist blinded to IADSA, plain CT and clinical data, independently reviewed hard-copy base and reconstructed maximum intensity projection images of the CTA and MRA studies. Thirty patients had a total of 63 aneurysms, 71.4% were 相似文献   

Characterisation of intracranial aneurysms with MR angiography

The purpose of this study was to compare the accuracy of 3D time-of-flight (TOF) acquisitions in the characterisation of intracranial aneurysms. Fourteen patients with aneurysms proven on intra-arterial angiography were first studied with a 3D TOF acquisition. When the aneurysms were incompletely demonstrated, additional MR angiography (MRA) acquisitions were performed, including black-blood MRA, 2D TOF, phase-contrast and contrast-enhanced TOF. 3D TOF MRA was sufficient for detection of the aneurysm in 13 of 14 cases and characterisation of the aneurysm was possible in 6. All the initial shortcomings of the TOF technique could be analysed and explained by means of additional MRA techniques. This study suggests that the combination of different MRA techniques offers new possibilities for noninvasive investigation of intracranial aneurysms.     

Acute subarachnoid Haemorrhage: 3D time-of-flight MR angiography versus intra-arterial digital angiography

To evaluate the efficacy and reliability of 3D time-of-flight MR angiography (TOF MRA) as a noninvasive procedure, 27 patients with acute subarachnoid haemorrhage (SAH) were studied with MRA immediately before or after intra-arterial digital subtraction angiography (DSA). 3DTOF MRA was performed with an axial slab of 60 mm centred on the circle of Willis and isotropic voxels. DSA showed 22 aneurysms and 1 dural arteriovenous fistula in 21 patients; the aneurysms ranged in size from 2 to 8 mm. MRA failed to show 2 small aneurysms, at the origin of the posterior and anterior communicating arteries. The 3D display of the intracranial vessels obtained with maximum intensity projection (MIP) or targetted MIP sometimes rendered the aneurysms better than DSA. However, due to its high spatial resolution, DSA more clearly defined the overall anatomy of the walls of the normal and abnormal vessels.1992 Scientific Award of the ESNR