Endovascular treatment of high-flow carotid cavernous fistulas by stent-assisted coil placement

BACKGROUND AND PURPOSE: Endovascular techniques are the methods of choice for the treatment of patients with carotid cavernous fistulas. We report our experience using stent-assisted coil placement for treatment of patients with high-flow fistulas that are associated with severe laceration of the internal carotid artery. METHODS: In a retrospective review of an internal endovascular therapy database covering the interval between October 2001 and October 2003, we identified a total of 5 patients presenting with 6 high-flow type A carotid cavernous fistulas (one had a bilateral fistula) that were associated with severe laceration of the internal carotid artery. All were treated first with stenting of the injured segment of the internal carotid artery followed by transarterial (3/6) and/or transvenous (4/6) obliteration of the fistula with detachable platinum coils. In 2 cases, a liquid adhesive was also used. In all instances, a compliant balloon was inflated within the stented arterial segment during coil deposition to avoid extension of coils into the parent artery. RESULTS: All 6 fistulas were obliterated, and each internal carotid artery was successfully reconstructed. Except for posttraumatic cranial nerve dysfunction in 1 patient, clinical outcome was very good. Follow-up angiograms in 3 of the 6 patients obtained at intervals between 3 and 6 months (mean, 4.5 months) revealed no fistula recurrence and no evidence of intimal hyperplasia within the stent. CONCLUSION: In this series of patients with high-flow carotid cavernous fistula associated with severe injury to the internal carotid artery, stent-assisted coil placement offered a safe and effective treatment. Stent-assisted coil placement may increase the ability to successfully treat fistulas with severe injury to the internal carotid artery with preservation of the parent artery.     

Assessment of collateral supply by two-coil continuous arterial spin labeling after coil occlusion of the internal carotid artery

A patient undergoing coil occlusion of a left internal carotid artery aneurysm was investigated by continuous arterial spin labeling MR imaging to evaluate perfusion territory mapping. Labeling was restricted to the left- or right-sided carotid artery by use of a separate neck coil. Before embolization, perfusion contrast was largely restricted to the labeled hemisphere. After embolization, perfusion contrast was created symmetrically in both hemispheres on labeling the right side, verifying sufficient collateral supply.     

Persistent primitive trigeminal artery associated with aneurysm: report of two cases and review of the literature

We present two cases of persistent primitive trigeminal artery (PPTA) associated with a giant aneurysm originating at the opening of the PPTA on the internal carotid artery (ICA). In one case, opening of the PPTA occurred 4 months after balloon occlusion of the ICA, when a giant aneurysm located at the cavernous segment of the ICA was being treated. The PPTA was occluded successfully using a Guglielmi detachable coil (GDC). A vertebral artery approach was taken. This is the first report of the opening of a PPTA associated with contrast filling of the aneurysm after balloon occlusion of the parent artery. The possibility of contrast filling of the aneurysm via potential PPTA should therefore be considered in the event of an ICA aneurysm with parent artery occlusion.     

MR angiography of the extracranial carotid arteries using a two-slab oblique 3-D acquisition.

PURPOSE: To describe an oblique, two-slab 3-D acquisition technique for MR angiography of the extracranial carotid arteries, an approach chosen to minimize saturation effects when the body coil is used as transmitter, as is often the situation when a dedicated neck coil is used as receiver. SUBJECTS: Five healthy subjects and 17 patients in whom carotid artery disease was suspected underwent MR angiography using the above technique. RESULTS: Flow contrast was much better than in direct sagittal acquisition. Comparisons between multislab transverse 3-D acquisition and the oblique approach showed that a greater length of the carotid arteries was depicted and scan time was less for oblique acquisitions. CONCLUSIONS: Use of oblique imaging is a simple and effective solution to the problem of coil-related saturation effects.     

Increased vessel depiction of the carotid bifurcation with a specialized 16‐channel phased array coil at 3T

The purpose of this work was to design and construct a multichannel receive‐only radiofrequency coil for 3T magnetic resonance imaging of the human carotid artery and bifurcation with optimized signal‐to‐noise ratio (SNR) in the carotid vessels along the full extent of the neck. A neck phantom designed to match the anatomy of a subject with a neck representing the body habitus often seen in subjects with carotid arterial disease was constructed. Sixteen circular coil elements were arranged on a semirigid fiberglass former that closely fit the shape of the phantom, resulting in a 16‐channel bilateral phased array coil. Comparisons were made between this coil and a typical 4‐channel carotid coil in a study of 10 carotid vessels in five healthy volunteers. The 16‐channel carotid coil showed a 73% average improvement in SNR at the carotid bifurcation. This coil also maintained an SNR greater than the peak SNR of the 4‐channel coil over a vessel length of 10 cm. The resulting increase in SNR improved vessel depiction of the carotid arteries over an extended field of view, and demonstrated better image quality for higher parallel imaging reduction factors compared to the 4‐channel coil. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.     

Three-dimensional time-of-flight MR angiography with a specialized gradient head coil

A gradient head coil has been developed, incorporating two independent gradients within the conventional body coil of the magnetic resonance (MR) system, with reduced rise times (200 μsec) and maximum amplitudes of 37 and 18 mT/m in the z and y directions, respectively. This gradient coil was systematically evaluated by testing two-dimensional (2D) and three-dimensional (3D) time-of-flight (TOF) MR angiography sequences applied to a pulsatile flow phantom simulating a carotid stenosis and the intracranial vasculature. When standard 2D and 3D TOF MR angiography techniques were used to image the carotid stenosis model, dramatic signal loss in the stenotic segment and a large flow void distal to the stenosis were seen. The shorter (3.8 msec) absolute echo times (TEs) achievable with the gradient coil in 3D sequences substantially reduced the phase dispersion and associated signal loss in the region of stenosis. Shorter TEs alone (3.2 msec) did not minimize signal loss, and firstorder flow compensation in the read and section-select directions provided further improvements (despite slightly longer TEs). Reduction of TEs in 2D sequences yielded relatively poor results regardless of the refocusing scheme or TE. This study confirms the predicted benefits of a dedicated coil with improved gradient capabilities for 3D MR angiography. The study suggests the limitations of 2D TOF MR angiography in the evaluation of severe stenoses.     

低剂量对比剂在64排CT头颈部血管联合成像中的应用

目的 评价低剂量对比剂在头颈部CT血管联合成像中的动脉分级能力及图像质量效果.资料与方法 搜集1183例行64排CT头颈部血管联合成像患者的资料,按对比剂注射剂量不同将患者分为低剂量组(n=708)和常规剂量组(n=475).观察容积重建图像上患者颈总动脉、颈内动脉颈段、颈内动脉岩骨段至颅内段、大脑前动脉及其主要分支血管的显示情况,根据最大密度投影上血管质量评分判定图像质量.结果 两组头颈部动脉血管及脑内较大分支在容积重建图像上显示良好,且最大密度投影图像上多数血管显示清晰,边缘光滑锐利.低剂量组和常规剂量组各段血管的显示率及图像质量评分差异均无统计学意义(P＞0.05).结论 低剂量对比剂在CT头颈部联合成像上可以很好地显示颅内血管,且具有较高的图像质量.     

血管内栓塞治疗颅内动脉瘤

目的 总结血管内栓塞治疗颅内动脉瘤经验。方法 股动脉Seldinger穿刺,先后应用MagicBD,Tracker-16,Tracker-10和Cordis 3F/2.5F微导管,送入球囊、不同长度的国产、进口游离微弹簧圈,配用MDS、GDC系统送入不同长度微弹簧圈、治疗颅内动脉海绵窦段动脉瘤5例、后交通动脉瘤1例、颈内动脉C2段动脉瘤3例、椎动脉颅内段动脉瘤3例、大脑后动脉瘤P2段动脉瘤1例,治疗颅内动脉C3－4段假性动脉瘤5例。结果 本组无1例死亡。球囊闭塞颈内动脉海绵窦段动脉瘤5例均痊愈,无并发症;微弹簧圈栓塞治疗动脉瘤栓塞达100％者9例、95％者2例,其中1例因血管痉挛遗留轻瘫,1例因MDS到位后不能顺利解脱导致部分脱垂于颈内动脉和大脑中动脉2cm,遗留轻瘫;5例假性动脉瘤完全治愈;闭塞载瘤动脉及动脉瘤的2例椎动脉完全治愈。结论 颈内动脉海绵窦段动脉瘤只要前、后交通动脉侧支循环代偿良好,可脱球囊闭塞载瘤动脉是安全有效的。微弹簧圈栓塞治疗颅内动脉瘤是一种有发展前途的治疗方法。     

Simultaneous subarachnoid hemorrhage and carotid cavernous fistula after rupture of a paraclinoid aneurysm during balloon-assisted coil embolization.

We describe an iatrogenic perforation of a paraclinoid aneurysm during balloon-assisted coil embolization that resulted in simultaneous subarachnoid contrast extravasation and a carotid cavernous fistula. The causative factors specifically related to the balloon-assisted method that led to aneurysm rupture are discussed as well as strategies for dealing with this complication.     

Geometrical optimization of a phased array coil for high-resolution MR imaging of the carotid arteries.

The geometry of an RF phased-array receiving coil for high-resolution MRI of the carotid artery, particularly the bifurcation, was optimized with respect to signal-to-noise ratio (SNR). A simulation tool was developed to determine homogeneity, sensitivity, and SNR for a given imaging situation. The algorithm takes into account the coil geometry, the parameters of the measured object, and the imaging parameters of the pulse sequence. The coil with the optimum geometry was implemented as a receive-only coil for 1.5 T and comparative SNR measurements with different coils were performed. The experimental SNR measurements verified the simulations. The optimized carotid artery phased array offered the best SNR over the desired field of view. In vivo high-resolution MRI of the carotid arteries of healthy volunteers and patients with known stenosis was conducted with the optimized phased array coil. The capability of the phased array coil for resolving components within the carotid artery walls is demonstrated. Magn Reson Med 50:439-443, 2003.     

Retrieval of an embolization coil from the internal carotid artery using the Amplatz Microsnare Retrieval System

An unusual case of unintentional release of an embolization coil into the proximal internal carotid artery is reported. The coil migrated and lodged distally in the petrous portion of the internal carotid artery during initial removal attempts using a regular nitinol loop snare. The coil was retrieved with the Amplatz Nitinol Microsnare system.     

Quadrature coil design for high-resolution carotid artery imaging scores better than a dual phased-array coil design with the same volume coverage

PURPOSE: To evaluate the ability of a custom-built coil design to provide improved signal-to-noise ratio (SNR) and less signal drop with increasing depth at the carotid artery. MATERIALS AND METHODS: Phased-array surface coils can provide a high SNR to image the carotid vessel wall. However, given the required field-of-view (FOV) and penetration depth, these coils show either a fast signal drop with increasing depth or a moderate SNR at increased coil size. A quadrature surface coil (a butterfly coil in conjunction with a linear single-loop coil) was compared with a phased-array coil in phantom and human studies. RESULTS: The phantom studies showed that the quadrature coil has better SNR over the required FOV than a standard phased-array coil (26% at 3 cm depth). CONCLUSION: The quadrature coil enables better image quality to be achieved.     

MR-Angiographie der supraaortalen Gefäße

PURPOSE: To compare high resolution contrast-enhanced MR angiography (MRA) and digital subtraction angiography (DSA) in the assessment of supraaortic vessel stenosis. METHODS: 14 patients with suspicion of cerebrovascular disease or upper limb ischemia underwent selective DSA and high resolution contrast enhanced MRA employing a new Panoramic-Array coil. Stenosis assessment in comparison to DSA followed NASCET criteria. Additionally signal-/noise ratios (SNR) were evaluated to assess contrast enhancement. RESULTS: Diagnostic image quality was achieved in all patients. Sensitivity and specificity for assessing high-grade stenosis of the supraaortic vessels were 100% and 96% respectively. In the assessment of high-grade common or internal carotid artery stenosis sensitivity and specificity was 100%. CONCLUSION: High resolution contrast enhanced supraaortic MRA combined with new coil systems allow for a reliable assessment of stenoses along the whole vessel course including the aortic arch. Previous stent procedures limit its use in postinterventional follow-up.     

犬颈总动脉实验性虹吸段血管模型的建立

目的 探讨截取一侧颈总动脉节段与另一侧颈总动脉端端吻合建立颅底段颈内动脉（虹吸段）血管模型的可行性.方法 对8只成年家犬应用显微外科技术,将玻璃管制成“S”形,一侧颈总动脉（CCA）作为母体动脉,截取另一侧颈总动脉节段穿过玻璃管模型与对侧CCA端端吻合.2周后作血管造影（CTA/DSA）证实模型内血流通畅.结果 8只犬均成功地建成颅底段颈内动脉（虹吸段）血管模型.结论 应用犬一侧颈总动脉节段与另一侧颈总动脉端端吻合建立颅底段颈内动脉（虹吸段）血管模型切实可行.     

Neuroform支架辅助弹簧圈填塞治疗颅内宽颈动脉瘤

目的 探讨 Neuroform支架辅助弹簧圈填塞治疗颅内宽颈动脉瘤的技术,并评价临床疗效和并发症.方法 采用Neuroform支架辅助技术对31例颅内宽颈动脉瘤进行了弹簧圈填塞治疗.31例患者共有颅内动脉瘤43枚,均为破裂动脉瘤,其中39枚为宽颈动脉瘤,21枚颈:体≥1,18枚颈:体<1;4枚为宽颈动脉瘤患者合并的非宽颈动脉瘤.结果 31例患者共置入支架35枚,其中3例患者两侧颈内动脉各置入1枚支架,1例两侧大脑中动脉各置入1枚.43枚动脉瘤中41枚进行了不同程度的填塞,2枚末行填塞.2例宽颈动脉瘤患者置入支架后出现非动脉瘤破裂性出血,均可能由于输送导丝损伤大脑中动脉分支引起;1例后交通动脉瘤患者,弹簧圈飘至大脑中动脉M2段,引起相应脑缺血症状.获随访的29例中无死亡病例和再次出血病例,28例生存良好,1例留有明显神经功能障碍.结论 支架辅助技术进行弹簧圈填塞治疗颅内宽颈动脉瘤是安全、有效的临床技术,可以拓宽颅内动脉瘤治疗的适应证.     

Embolization of experimentally created aneurysms with a laser-activated detachable coil device.

Our experimental study in dogs suggests that laser-activated detachable coil devices show promise in the embolization of carotid aneurysms, allowing the interventionalist greater control than possible with nonretractable coil systems and permitting detachment of the coil from the wire in seconds.     

Evaluation of a dedicated dual phased-array surface coil using a black-blood FSE sequence for high resolution MRI of the carotid vessel wall

PURPOSE: To investigate the ability of magnetic resonance imaging (MRI) to visualize the carotid vessel wall using a phased-array coil and a black-blood (BB) fast spin-echo (FSE) sequence. MATERIALS AND METHODS: The phased-array coil was compared with a three-inch coil. Images from volunteers were evaluated for artifacts, wall layers, and wall signal intensity. Signal intensity and homogeneity of atherosclerosis were assessed. Lumen diameter and vessel area were measured. RESULTS: Comparison between the phased-array coil and the three-inch coil showed a 100% increase in signal-to-noise ratio. BB-FSE imaging resulted in good delineation between blood and vessel wall. Most volunteers had a two-layered vessel wall with a hyperintense inner layer. MRI showed both homogeneous hyperintense and heterogeneous plaques, which consisted of a main hyperintense part with hypointense spots and/or intermediate regions. MRI lumen and area measurements were performed easily. CONCLUSION: High resolution MRI of carotid atherosclerosis is feasible with a phased-array coil and a BB-FSE sequence.     

Multislice perfusion and perfusion territory imaging in humans with separate label and image coils.

An arterial spin labeling technique using separate RF labeling and imaging coils was used to obtain multislice perfusion images of the human brain at 3 T. Continuous RF irradiation at a peak power of 0.3 W was applied to the carotid arteries to adiabatically invert spins. Labeling was achieved without producing magnetization transfer effects since the B1 field of the labeling coil did not extend into the imaging region or couple significant power into the imaging coil. Eliminating magnetization transfer allowed the acquisition of multislice perfusion images of arbitrary orientation. Combining surface coil labeling with a reduced RF duty cycle permitted significantly lower SAR than single coil approaches. The technique was also found to allow selective labeling of blood in either carotid, providing an assessment of the artery's perfusion territory. In normal subjects, these territories were well-defined and localized to the ipsilateral hemisphere.     

Isolated progressive visual loss after coiling of paraclinoid aneurysms

BACKGROUND AND PURPOSE: The proximity of the paraclinoid segment of the internal carotid artery to the visual pathways may result in visual deficits when patients present with aneurysms in this segment. Although surgical clip ligation of these aneurysms has been the standard of care for decades, the advent of coil embolization has permitted endovascular therapy in those aneurysms with favorable dome-to-neck ratios. Although immediate nonprogressive visual loss after coil embolization of paraclinoid aneurysms has been well described, isolated progressive visual loss immediately or shortly following coil embolization, to our knowledge, has not. We have identified 8 patients who experienced progressive loss of vision, unassociated with any other neurologic deficits, developing immediately or shortly after apparently uncomplicated coil embolization of a paraclinoid aneurysm. MATERIALS AND METHODS: This study is a retrospective case series of 8 patients seen at 4 separate academic institutions. Inpatient and outpatient records were examined to determine patient demographics, previous ocular and medical history, and ophthalmic status before endovascular embolization. In addition, details of the primary endovascular therapy and subsequent surgical and nonsurgical interventions were recorded. Follow-up data, including most recent best-corrected visual acuity, postoperative course, and duration of follow-up were documented. RESULTS: Eight patients developed progressive visual loss in 1 or both eyes immediately or shortly after apparently uncomplicated coiling of a paraclinoid aneurysm. MR imaging findings suggested that the visual loss was most likely caused by perianeurysmal inflammation related to the coils used to embolize the aneurysm, enlargement or persistence of the aneurysm despite coiling, or a combination of these mechanisms. Most patients experienced improvement in vision, 2 apparently related to treatment with systemic corticosteroids. CONCLUSION: Patients in whom endovascular treatment of a paraclinoid aneurysm is contemplated should be warned about the potential for both isolated nonprogressive and progressive visual loss in 1 or both eyes. Patients in whom progressive visual loss occurs may benefit from treatment with systemic corticosteroids.     

Routine MR imaging of the internal carotid artery siphon: angiographic correlation with cervical carotid lesions

This study correlates the appearance of the cavernous segment of the carotid artery on MR images with the presence of significant stenosis or occlusion of the cervical carotid artery as seen on angiograms in 100 patients who had brain MR imaging and arteriography within a 1-week period. Four patients demonstrated isointense signal within the carotid artery's cavernous segment; two of these findings correlated with complete carotid occlusion as seen angiographically, while partial compromise was seen angiographically in the other two. Four other patients had variable signal intensity and irregularity of the luminal outline in the carotid siphon, correlating with angiographic evidence of atheromatous disease in three patients and of dissection in one patient. The demonstration of normal signal void within a normal-appearing cavernous segment of the internal carotid artery in the remaining 92 patients correlated with absence of significant stenosis within the cervical segment in 86 patients. In the remaining six, significant disease of the internal carotid artery was found. Isointensity within the intracranial carotid artery can indicate either complete occlusion or very slow flow. Therefore, angiography is still necessary to completely exclude potentially treatable disease that produces very slow flow leading to isointensity. The presence of normal flow void in the intracranial segment does not exclude significant compromise of the cervical segment of the carotid artery.