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Aims and Hypothesis: Giant intracranial aneurysms have a poor prognosis mainly due to their high risk of rupture. Because their incidence is low, clinical trial evidence for adequate treatment is lacking. The Giant Intracranial Aneurysm Registry is designed to document current treatment strategies in giant aneurysm care and to monitor the course of the disease over five-years. It aims to evaluate the hypothesis that all three possible branches of therapy (conservative/endovascular/surgical) lead to equal rupture rates., Design: The Giant Intracranial Aneurysm Registry is an interdisciplinary multicenter observational study. Each center recruits patients diagnosed with a giant intracranial aneurysm both prospectively and retrospectively. Primary outcome will be the aneurysm rupture rate at five-years of follow-up., Study Outcome: Patient enrollment has begun at 20 neurovascular centers throughout Germany, with 19 further centers applying for local ethics approval to take part in the study. The first nine months are designed as a pilot phase followed by the integration of study centers throughout the EU and the initiation of separate sub-studies., Discussion: Giant intracranial aneurysms have often been ignored or marginalized due to their low incidence. The Giant Intracranial Aneurysm Registry aims to lead to a better understanding of these complex lesions and to serve as a basis for the development of future clinical studies., (© 2011 The Authors. International Journal of Stroke © 2011 World Stroke Organization.)

Intracranial aneurysms may be treated by flow diverters, alternatively to stents and coils combination. Numerical simulation allows the assessment of the complex nature of aneurismal flow. Endovascular devices present a rather dense and fine strut network, increasing the complexity of the meshing. We propose an alternative strategy, which is based on the modeling of the device as a porous medium. Two patient-specific aneurysm data sets were reconstructed using conventional clinical setups. The aneurysms selection was done so that intra-aneurismal flow was shear driven in one and inertia driven in the other. Stents and their porous medium analog were positioned at the aneurysm neck. Physiological flow and standard boundary conditions were applied. The comparison between both approaches was done by analyzing the velocity, vorticity, and shear rate magnitudes inside the aneurysm as well as the wall shear stress (WSS) at the aneurysm surface. Simulations without device were also computed. The average flow reduction reaches 76 and 41% for the shear and inertia driven flow models, respectively. When comparing the two approaches, results show a remarkable similarity in the flow patterns and magnitude. WSS, iso-velocity surfaces and velocity on a trans-sectional plane are in fairly good agreement. The root mean squared error on the investigated parameters reaches 20% for aneurysm velocity, 30.6% for aneurysm shear rate, and 47.4% for aneurysm vorticity. It reaches 20.6% for WSS computed on the aneurysm surface. The advantages of this approach reside in its facility to implement and in the gain in computational time. Results predicted by the porous medium approach compare well with the real stent geometry model and allow predicting the main effects of the device on intra-aneurismal flow, facilitating thus the analysis.

Objective: The mechanisms by which smoking and hypertension lead to increased incidence of intracranial aneurysm (IA) formation remain poorly understood. The current study investigates the effects of these risk factors on wall shear stress (WSS) and oscillatory shear index (OSI) at the site of IA initiation., Methods: Two (n=2) IAs from two patients with history of smoking and hypertension were artificially removed with the help of software @neuFuse (Supercomputing Solutions, Bologna, Italy) and the vessel geometry reconstructed to mimic the condition prior to IA formation. Two computational fluid dynamics (CFD) analyses were performed on each data-set by using in turn the normal physiological values of blood viscosity (BV), and high BV values specific to smoking and hypertension, obtained from literature., Results: At normal BV, high WSS (>15 Pa) was observed at the site of IA initiation in both patients. When BV values specific to smoking and hypertension were used, both the areas affected by high WSS (>15 Pa) and the maximum WSS were increased whilst the magnitude and distribution of OSI showed no significant change., Conclusions: Long-term exposure to high WSS may result in an increased risk of IA development. An incremental increase in areas of high WSS observed secondary to smoking and hypertension may indicate a further increase in the risk of IA initiation. Interestingly, the relationship between BV and the area of increased WSS was not linear, reflecting the need for patient-specific CFD analysis., (Crown Copyright 2010. Published by Elsevier B.V. All rights reserved.)

Objectives: Hemodynamic changes in the cerebral circulation in presence of coarctation of aorta (CoA) and their significance in the increased intracranial aneurysms (IAs) formation in these patients remain unclear. In the present study, we measured the flow-rate waveforms in the cerebral arteries of a patient with CoA, followed by an analysis of different hemodynamic indices in a coexisting IA., Materials and Methods: Phase-contrast Magnetic Resonance (pc-MR) volumetric flow-rate (VFR) measurements were performed in cerebral arteries of a 51 years old woman with coexisting CoA, and five healthy volunteers. Numerical predictions of a number of relevant hemodynamic indices were performed in an IA located in sub-clinoid part of left internal carotid artery (ICA) of the patient. Computations were performed using Ansys(®)-CFX(™) solver using the VFR values measured in the patient as boundary conditions (BCs). A second analysis was performed using the average VFR values measured in healthy volunteers. The VFR waveforms measured in the patient and healthy volunteers were compared followed by a comparison of the hemodynamic indices obtained using both approaches. The results are discussed in the background of relevant literature., Results: Mean flow-rates were increased by 27.1% to 54.9% (2.66-5.44 ml/sec) in the cerebral circulation of patients with CoA as compared to healthy volunteers (1.2-3.95 ml/sec). Velocities were increased inside the IA by 35-45%. An exponential rise of 650% was observed in the area affected by high wall shear stress (WSS>15Pa) when flow-rates specific to CoA were used as compared to population average flow-rates. Absolute values of space and time averaged WSS were increased by 65%. Whereas values of maximum pressure on the IA wall were increased by 15% the area of elevated pressure was actually decreased by 50%, reflecting a more focalized jet impingement within the IA of the CoA patient., Conclusions: IAs can develop in patients with CoA several years after the surgical repair. Cerebral flow-rates in CoA patients are significantly higher as compared to average flow-rates in healthy population. The increased supra-physiological WSS (>15Pa), OSI (>0.2) and focalized pressure may play an important role in the etiopathogenesis of IAs in patients with CoA.

Objective: The importance of hemodynamics in the etiopathogenesis of intracranial aneurysms (IAs) is widely accepted. Computational fluid dynamics (CFD) is being used increasingly for hemodynamic predictions. However, alogn with the continuing development and validation of these tools, it is imperative to collect the opinion of the clinicians., Methods: A workshop on CFD was conducted during the European Society of Minimally Invasive Neurological Therapy (ESMINT) Teaching Course, Lisbon, Portugal. 36 delegates, mostly clinicians, performed supervised CFD analysis for an IA, using the @neuFuse software developed within the European project @neurIST. Feedback on the workshop was collected and analyzed. The performance was assessed on a scale of 1 to 4 and, compared with experts' performance., Results: Current dilemmas in the management of unruptured IAs remained the most important motivating factor to attend the workshop and majority of participants showed interest in participating in a multicentric trial. The participants achieved an average score of 2.52 (range 0-4) which was 63% (range 0-100%) of an expert user., Conclusions: Although participants showed a manifest interest in CFD, there was a clear lack of awareness concerning the role of hemodynamics in the etiopathogenesis of IAs and the use of CFD in this context. More efforts therefore are required to enhance understanding of the clinicians in the subject.

Percutaneous vertebroplasty (PVP) is carried out under fluoroscopic control in most centers. The exclusion of implant leakage and the assessment of implant distribution might be difficult to assess based on two-dimensional radiographic projection images only. We evaluated the feasibility of performing a follow-up examination after PVP with rotational acquisitions and volumetric reconstructions in the angio suite. Twenty consecutive patients underwent standard PVP procedures under fluoroscopic control. Immediate postprocedure evaluation of the implant distribution in the angio suite (BV 3000; Philips, The Netherlands) was performed using rotational acquisitions (typical parameters for the image acquisition included a 17-cm field-of-view, 200 acquired images for a total angular range of 180 degrees ). Postprocessing of acquired volumetric datasets included multiplanar reconstruction (MPR), maximum intensity projection (MIP), and volume rendering technique (VRT) images that were displayed as two-dimensional slabs or as entire three-dimensional volumes. Image evaluation included lesion and implant assessment with special attention given to implant leakage. Findings from rotational acquisitions were compared to findings from postinterventional CT. The time to perform and to postprocess the rotational acquisitions was in all cases less then 10 min. Assessment of implant distribution after PVP using rotational image acquisition methods and volumetric reconstructions was possible in all patients. Cement distribution and potential leakage sites were visualized best on MIP images presented as slabs. From a total of 33 detected leakages with CT, 30 could be correctly detected by rotational image acquisition. Rotational image acquisitions and volumetric reconstruction methods provided a fast method to control radiographically the result of PVP in our cases.

We developed a method to produce tubular in vitro models of the cerebral vessels from real patient data. Three-dimensional data sets obtained from patients undergoing rotational angiography were used for stereolithographic biomodeling by using rapid prototyping technology. In a second step, tubular reproductions of the cerebral vessels were obtained by using the lost-wax technique. These reproductions can be useful for hemodynamic research and for the development and preclinical evaluation of new endovascular treatment methods.

Purpose: To describe a new fluoroscopically guided technique for osteoplasty (or cementoplasty) of the superior and inferior pubic rami and ischial tuberosities and to provide information about the access routes and initial results on pain management after this technique., Materials and Methods: Twenty-three lytic metastases of the superior and inferior pubic rami and ischial tuberosities were treated in 14 consecutive patients. Percutaneous access of the bones was performed under fluoroscopy. All patients had pain refractory to radiation and narcotic therapy and were unsuitable candidates for surgery according to multidisciplinary consensus., Results: Technical success was achieved in all cases. Clinically, effective pain relief was obtained in 92% of patients. One intraarticular asymptomatic minor complication and one major complication resulting from leakage near the pudendal nerve were observed. The latter was subsequently treated by radiofrequency ablation., Conclusion: Pelvic osteoplasty appears to be a safe and highly effective palliative therapy for painful osteolytic malignant bone metastases.

Object: This study was designed to determine whether the frequency of shunt-dependent hydrocephalus in patients suffering from aneurysmal subarachnoid hemorrhage (SAH) differs when comparing surgical clip application with endovascular obliteration of ruptured aneurysms., Methods: In this prospective nonrandomized study, 245 patients with aneurysmal SAH treated using either surgical clip application or endovascular coil embolization were studied at our institution between September 1997 and March 2003. One hundred eighty patients underwent clip application and 65 had coil embolization. In those patients who underwent clip application of anterior circulation aneurysms, the lamina terminalis was systematically fenestrated. The occurrence of acute, asymptomatic, and shunt-dependent hydrocephalus was analyzed in both treatment groups. A subgroup analysis of patients with good clinical grade (World Federation of Neurosurgical Societies [WFNS] Grades I-III) and better Fisher Grade (1-3) and of patients with Fisher Grade 4 hemorrhage was performed. Acute hydrocephalus was observed in 19% of surgical cases and 46% of endovascular ones. The occurrence of asymptomatic hydrocephalus was similar in both treatment groups (p = 0.4). Shunt-dependent hydrocephalus occurred in 14% of surgical cases and 19% of endovascular cases. This difference did not reach statistical significance (p = 0.53). Logistic regression models controlling for patient age, WFNS grade, Fisher grade, and acute hydrocephalus in patients with good clinical grade and better Fisher grade revealed no significant difference in the rate of shunt-dependent hydrocephalus in both therapy groups (odds ratio [OR] 0.8, 95% confidence interval [CI] 0.2-2.65). Results of similar models indicated that among patients with intraventricular hemorrhage (IVH), surgical clip application carried a lower risk of shunt-dependent hydrocephalus (OR 0.32, 95% CI 0.14-0.75) compared with that for endovascular embolization., Conclusions: Shunt-dependent hydrocephalus was comparable in the two treatment groups, even in patients with better clinical and radiological grades on admission. Only patients in the endovascular therapy group who had experienced IVH showed a higher likelihood of shunt-dependent hydrocephalus.

Background Context: Transpedicular vertebroplasty is an effective procedure to reduce pain and stabilize osteoporotic vertebral fractures. It is, however, difficult to perform after transpedicular instrumentation because the pedicle screws are in the way., Purpose: To determine if vertebroplasty can be performed in patients who have previously undergone osteosynthesis pedicle-screw fixation., Study Design: We postulate that an alternate transdiscal route can be used in cases with instrumentation in order to successfully perform vertebroplasty., Methods: We report the case of a 73-year-old male patient presenting with a fresh osteoporotic fracture of L2 and L3 6 weeks after having undergone a dorsal operative stabilization between L3 and L5., Results: Vertebroplasty was performed using a transdiscal descending approach to treat the two adjacent vertebral levels. The patient reported a 50% decrease in pain and was able to walk with a stick at 3 months. At late follow-up at 18 months his walking had further improved and he experienced only sporadic lumbar pain., Conclusions: Vertebroplasty can be performed in patients having previously undergone transpedicular instrumentation. The transdiscal route represents such a new approach.

The purpose of this study was to describe a balloon-assisted double-lumen microcatheter technique to perform a controlled and tight coil packing of a vascular segment for vessel occlusion. This technique can be performed immediately after a test occlusion with the balloon kept in place and was, as illustrated in six cases, in our experience safe, straight forward to use and fast.

Summary: We introduce our training tools and system of neurovascular intervention. An in vitro cerebral vascular model was used for the young residents to understand the basic interventional techniques and devices. The model included several vascular lesions such as cerebral aneurysm, dural arterio-venous fistula, or carotid artery stenosis. Endovascular procedures in the model were performed under fluoroscopic or direct visual control, and consecutive haemodynamic changes were visualized by using digital subtraction angiography and direct observation. Thus, traineess could have an easy understanding of clinical conditions. New medical devices, such as platinum coils, were successfully implanted in the model under stable conditions. After the initial training using vascular model, the residents had started clinical experiences under the control of senior surgeons. Although it is difficult to describe usefulness of our clinical training, we believe that we provide enough good quality and quantity of clinical cases to the residents. Because our endovascular team has recently had150-200 interventional procedures every year, one resident can have experienced more than 100 cases per year. The qualification of a Board Certified Specialist of the Japanese Society of Intravascular Neurosurgery (JSIN) requires that the applicant must have experienced more than 100 cases for four years. So our residents can have enough case materials to qualify the board examination.

Background: Cerebral vasospasm is the most common cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (SAH). This study is designed to determine whether the incidence of symptomatic vasospasm and the overall clinical outcome differ between patients treated with surgical clipping compared with endovascular obliteration of aneurysms., Methods: In this prospective study, 98 patients with aneurysmal SAH were treated. Seventy-two patients underwent surgery and clipping and 26 had coil embolization. The incidence of symptomatic vasospasm, permanent neurologic deficit due to vasospasm and clinical outcome were analyzed. Patients with better clinical and radiological grades (World Federation of Neurological Surgeons grades I-III and Fisher grades I-III) were analyzed separately., Results: Symptomatic vasospasm occurred in 22% of the patients; 25% in the surgical group and 15% in the endovascular group. Nine percent of the patients in the surgical group and 7% in the endovascular group suffered ischemic infarction with permanent neurological deficit. These differences did not reach statistical significance (p = 0.42). For patients with better clinical and radiological grades, no significant difference was found for the rate of symptomatic vasospasm; 23% in the surgical and 12% in the endovascular group (p = 0.49). The overall clinical outcome was comparable in both groups, with no difference in the likelihood of a Glasgow Outcome Scale score of 3 or less (15% in the surgical and 16% in the endovascular group; p = 0.87). The same results for outcome were obtained for the subgroup of patients with better clinical grades on admission., Conclusion: Symptomatic vasospasm and ischemic infarction rate seem comparable in both groups, even for patients with better clinical and radiological admission grades. There is no significant difference in the overall clinical outcome at the long-term follow-up between both groups., (Copyright 2004 S. Karger AG, Basel)

Summary: Atheromatous stenoses at the carotid bifurcation were treated by angioplasty and Wallstenting with cerebral protection obtained in most cases by temporary occlusion of the internal carotid artery. 287 carotid stenoses were treated in 233 patients. The stenosis was symptomatic in 79% of cases. All patients presented either a stenosis of >70% with significant impairment of the cerebral circulation (281 cases) or a symptomatic ulcerated plaque (six cases). A self-mounted protection system was used in 177 cases, the Percusurge Guardwire protection device in 98 cases an EPI filter in 12 cases. There was a contralateral internal carotid occlusion in 13% of cases. A combined stenting (vertebral, siphon, subclavian) was performed in 14% of cases. A Rolling membrane Wallstent was used in 84 patients, a first generation Easy Wallstent in 38 cases, a "Carotid" Easy Wallstent 35 in 55 cases and monorail 14 in 110 cases. Full opening of the stenosis was obtained in 98% of patients with correction of the arterial curve and improvement of the cerebral vascular supply. There were 0.7% cases with transient symptomatic neurological complications and 2% with permanent sequelae mainly related to avoidable inadequacy in flushing or to the insufficient radial force of the first generation Easy Wallstent. There were no per and one post-procedural cardiac complication (0.6%) in the s165 cases performed with the "Carotid" Easy Wallstent. Follow-up angiograms showed 0.7% of restenoses. Still in evolution, endovascular treatment of atheromatous stenoses at the carotid bifurcation with cerebral protection and stenting is a promising alternative technique to surgery. The association of Carotid Easy Wallstent 14 monorail and Percusurge Guardwire appears to be currently satisfactory.

The purpose of this study was to evaluate the potential of high quality computed tomographic angiography (CTA) to replace digital subtraction angiography (DSA) in cases of ruptured saccular aneurysms and perform early surgical clipping or coiling on the basis of CTA alone. In a prospective study, 100 patients with aneurysmal subarachnoid haemorrhage (SAH) diagnosed by computed tomography underwent CTA. CTA revealed a total of 118 aneurysms including all ruptured aneurysms. A decision of direct surgical clipping, endovascular coiling or therapeutic abstention was made in 89 cases (89%) on the basis of CTA alone. Sixty-one direct surgical procedures were performed after CTA. Twenty-six cases underwent DSA for immediate endovascular treatment of the ruptured aneurysm. In 11 cases (11%), a DSA was performed prior to the therapeutic decision because of unclear aneurysm. Four cases were not treated because of initial poor clinical grade. The surgical findings were compared with CTA data and were considered accurate in all but one case. All patients underwent postoperative DSA within 10 days after SAH. The sensitivity and the specificity of CTA for the detection of all aneurysms, as compared with postoperative DSA, were 95.1 and 100%, respectively. A total of six unruptured aneurysms were missed initially, but were visible retrospectively on CTA in all but one case and were found in patients with multiple aneurysms in whom the ruptured aneurysm was detected by CTA. Current quality CTA allows reliable pretreatment planning for the majority of cases of aneurysmal subarachnoid haemorrhage and diminishes the pretreatment evaluation time critically. Complementary pretreatment DSA is required in situations where CTA characteristics of the ruptured aneurysm is unsatisfactory.

Artificial models of cerebral aneurysms for medical training and testing of medical devices were constructed from corrosion casts of the main cerebral arteries of a human specimen. Three aneurysms with a variety of shapes were simulated at typical locations. Rigid and soft models were made of silicone using the "lost wax" technique. The transparent silicone models were anatomically accurate and reproducible copies of human vascular casts. These models could be connected in a closed circuit that used an electric pump to simulate pulsatile flow. Endovascular procedures and surgical clip application were performed under fluoroscopic or direct visual control. Surgical clipping, endoluminal coil manipulation, and consecutive hemodynamic changes were visualized by digital subtraction angiography and direct observation. The model provides trainee surgeons with an understanding of clinical conditions. New medical devices, such as platinum coils, would be experimentally implanted in the model under stable conditions. These anatomically accurate and reproducible models of cerebral vasculature and aneurysms are valuable for medical testing, training, and research.

Study Design: Technical note., Objective: To describe a technique for performing percutaneous vertebroplasty of C1 for treatment of osteolytic metastatic disease involving the lateral portions of the atlas in which precautions are taken to protect the vertebrobasilar arterial supply and a posterior access route is used for cement delivery., Summary of Background Data: Percutaneous vertebroplasty (PVP) has proved to be efficient for the treatment of painful osteolytic vertebral disease. Good clinical experience with this technique suggested its extension to stabilize a painful osteolytic lesion of the atlas., Methods: A patient with known parotid cancer presented with neck pain refractory to conservative treatment. On computed tomography, osteolytic destruction of the atlas that mainly involved the right lateral mass and surrounded the vertebral artery was found. On digital subtraction angiography, the lesion was shown to be highly vascularized and supplied mainly by direct branches of the ipsilateral vertebral artery. To avoid the risk of cement reflux from the tumor vascular bed to the involved vertebral artery, coil occlusion of the involved V3 segment was performed before vertebroplasty. Percutaneous vertebroplasty was then carried out using a percutaneous posteroanterior direction access route., Results: Satisfactory filling of the osteolytic lesion with cement was achieved radiologically. Three days after the intervention and at a 9-month follow-up examination, the patient was free of pain., Conclusions: Vertebroplasty used to treat an osteolytic lesion of the atlas involving the lateral mass was performed by a posterior percutaneous approach. To prevent vertebrobasilar embolism, the involved vertebral artery was occluded before polymer injection.

Non-aqueous solvents have long been used in subcutaneous or intramuscular pharmaceutical formulations to dissolve water-insoluble drugs. In recent years, the need for these vehicles was increased since the drug discovery process has yielded many poorly water-soluble drugs. Besides, preparations containing embolic materials dissolved in undiluted non-aqueous water-miscible solvents have been proposed for the intravascular treatment of aneurysms, arteriovenous malformations, or tumors. These organic solvents, regarded as chemically and biologically inert, may show pharmacological and toxicological effects. Therefore, knowledge of tolerance and activity of non-aqueous solvents is essential before they can be administered, especially when given undiluted. This paper focuses on thirteen organic solvents reported as possible vehicles for injectable products and details toxicological data when they have been administered intravascularly. These solvents can be subdivided into three groups according to their description in the literature either for intravenous pharmaceutical parenterals or for intravascular embolic liquids: well-documented organic solvents (propylene glycol, polyethylene glycols, ethanol), solvents described in specific applications (dimethyl sulfoxide, N-methyl-2-pyrrolidone, glycofurol, Solketal, glycerol formal, acetone), and solvents not reported in intravascular applications but potentially useful (tetrahydrofurfuryl alcohol, diglyme, dimethyl isosorbide, ethyl lactate). This review of the literature shows that toxicity data on intravascular organic solvents are insufficient because they concern solvents diluted with water and because of the lack of comparative evaluation using the same methodologies.

Using carotid bifurcation phantom models with different degrees of stenoses, we evaluated the accuracy of vessel lumen representation on MR images obtained from the inverse Fourier transform of different k-space percentages. Our results show that the lower thresholds of truncated k-space sampling are dictated by the severity of luminal narrowing. The defined thresholds may help improve efficiency of 3D MR imaging of the carotid arteries while maintaining adequate luminal representation.

Here we describe an anatomic structure that takes the form of a venous channel (VC) within the two layers of the lateral wall of the cavernous sinus (CS). Colored gelatin was injected in both superficial middle cerebral veins (SMCV) of 29 human specimens. When a SMCV terminated into the CS, the latter was dissected giving particular attention to its lateral wall. The termination of the VC and its eventual communications with the CS and adjacent venous structures were studied. A VC in the lateral wall of the CS was found in 14 of 58 lateral walls (24.1%). It was in continuation with the SMCV in 13 cases, with the uncal vein in one case. The VC drained into the superior petrosal sinus (71.4%), the pterygoid plexus (21.4%), or the posterior part of the CS (7.2%). Two alternate drainage pathways for the SMCV were observed, toward the anterosuperior aspect of the CS (13.8%) or through a paracavernous sinus located along the floor of the middle cranial fossa (32.8%). These different pathways were not observed to occur concomitantly. SMCV were absent in 29.3%. Despite its close topographic relation with the CS, the VC in the lateral wall can be considered as an anatomic entity with potential clinical relevance. We propose to call it the laterocavernous sinus.

The authors report the complications that occurred in their experience with performing recanalization procedures in the internal carotid artery and present their treatment strategies. The complications can be classified into those that were periprocedural and those that were postprocedural. The former include complications related to the vascular-approach access site of and those associated with the dilation and stenting procedure. Other complications observed included embolic events, dissection, vascular spasm, bradycardia, inappropriate dilation, occlusion of the external carotid artery, and rare, unusual complications such as the occurrence of iatrogenic cavernous carotid fistula. Postprocedure complications occurred in the hours and days following the procedure in the form of embolic and occlusive events, and hypotension and bradycardia were seen as late complications in the months following the procedure. The authors discuss how such complications occur and provide suggestions on how to avoid them. The role of stent placement and the potential use of protective devices are explored. Overall, adequate use of currently available systems allows for safe application of endovascular treatment techniques that avoid altogether or treat these potential complications. A reduced incidence of complications related to the initial individual learning curve may be obtained with preclinical training, in which use of invitro models should be considered. Surgical standby no longer seems required; however, early posttreatment surveillance in intensive care unit is mandatory to avoid the remaining primary complications.

Purpose: To assess the effectiveness, initial and long term, of embolization using polyvinyl alcohol particles (PVA) particles in patients with spinal dural arteriovenous fistulas (SDAVF)., Methods: The initial treatment in 14 patients with SDAVF was embolization with PVA particles. Postembolization occlusion of the SDAVF was documented angiographically in all cases., Results: All 14 patients initially showed an improvement in clinical symptoms, but the neurologic status of 11 patients subsequently deteriorated. Of the 11 patients who had recurrence of symptoms, nine had angiographically proven recurrences of their SDAVF while two had negative follow-up of spinal angiography. PVA embolization is ineffective for the treatment of SDAVF and is not without risk., Conclusion: On the basis of a literature review of the other two alternative treatments (operation or liquid adhesive embolization) available for SDAVF and our preliminary experience with N-butyl cyanoacylate (NBCA) embolization, we suggest that NBCA embolization be the initial treatment of choice for SDAVF; if that procedure is not possible, or is unsuccessful, then operation is recommended.

Twenty-seven patients with 14 aneurysms and 17 vascular malformations were each examined with both time-of-flight (TF) and phase-contrast (PC) magnetic resonance angiography of the head. Three-dimensional (3D) PC imaging depicted the patent lumen of the aneurysms, while 3D TF imaging depicted the patent lumen and a subacute thrombus if present. The 3D PC techniques were superior to 3D TF methods in depicting aneurysms larger than 15 mm. PC angiography allowed velocity resolution of vascular lesions and yielded functional flow information by directly depicting collateral flow to vascular lesions. Artifacts present on TF images were due to substances with short T1, hemosiderin, and surgical clips. Artifacts present on PC images were due to flow-related aliasing. The results showed that PC techniques have specific advantages over TF techniques, including identification of large aneurysms, velocity resolution of vascular lesions, depiction of flow direction about the circle of Willis, and less degradation by artifacts.

Atherosclerotic plaques that develop in the extracranial circulation are usually extensively vascularized by vasa vasorum. However, human vasa vasorum associated with intracranial atherosclerosis has not been adequately addressed. Anterior and posterior circulation specimens from fresh autopsy material were studied under the magnification of a dissecting microscope and proliferative vasa vasorum was found to be frequently associated with intrinsic atheromatous plaques. Vasa vasorum associated with an incidental large aneurysm supports the radiological literature demonstrating that many large and giant thick-walled aneurysms exhibit vascularized walls on contrast computed tomography scans. This information may aid in the preoperative assessment and possible repair of these aneurysms.

The group of six patients in this study experienced delayed visual loss following head trauma. Visual loss occurred from 1 day to 13 years after the initial injury. All patients suffered indirect trauma to the internal carotid artery resulting in formation of either an aneurysm or pseudoaneurysm or a carotid-cavernous fistula. Review of the radiologic and clinical findings was performed in six patients. The diagnosis was established by computed tomography, magnetic resonance imaging, and angiography. All patients had follow-up clinical evaluation and imaging studies. Treatment by neurosurgical or interventional neuroradiologic procedures resulted in significant visual improvement in five patients. Different pathophysiologic mechanisms could be correlated with the delayed visual loss produced by the two types of lesions. The pathologic changes associated with the aneurysms/pseudoaneurysms included direct compression of optic nerves and/or chiasm and intracranial hematoma. A carotid-cavernous fistula caused delayed visual loss by either hematoma at the orbital apex or compression of the chiasm and/or optic nerves by saccular dilatation of the cavernous sinus. The delayed onset of decreased vision following head trauma should alert the physician to the possibility of a traumatic aneurysm/pseudoaneurysm or a carotid-cavernous fistula. Different neuro-ophthalmologic symptoms can usually be correlated with the pathologic changes demonstrated by neuroimaging procedures.