Endovascular treatment of head and neck arteriovenous malformations.

INTRODUCTION: Head and neck arteriovenous malformations (H&N AVM) are associated with considerable clinical and psychosocial burden and present a significant treatment challenge. We evaluated the presentation, response to treatment, and outcome of patients with H&N AVMs treated by endovascular means at our institution. METHODS: Patients with H&N AVMs treated by endovascular means from 1984 to 2012 were evaluated retrospectively. These included AVMs involving the scalp, orbit, maxillofacial, and upper neck localizations. Patient's clinical files, radiological images, catheter angiograms, and surgical reports were reviewed. RESULTS: Eighty-nine patients with H&N AVMs (46 females, 43 males; 48 small, 41 large) received endovascular therapy. The goals of treatment were curative (n = 30), palliative (n = 34), or presurgical (n = 25). The total number of endovascular treatment sessions was 244 (average of 1.5 per patient). The goal of treatment was met in 92.1 % of cases. Eventual cure was achieved in 42 patients accounting for 58.4 % (52/89) of all patients who underwent treatment for any goal. Twenty-eight of these patients were cured by embolization alone (28/89, 31.4 %) of which 18 were single-hole AVFs. Twenty-four were cured by planned surgical excision after presurgical embolization (24/89, 27 %). Seven patients (7/89, 7.2 %) suffered transient and two (2/89, 2.2 %) permanent endovascular treatment complications. CONCLUSION: Endovascular treatment is effective for H&N AVMs and relatively safe. It is particularly effective for symptom palliation and presurgical aid. Embolization is curative mostly in small lesions and single-hole fistulas. In patients with large non-curable H&N AVMs, endovascular therapy is often the only palliative option.

Ticagrelor versus Clopidogrel in the Dual Antiplatelet Regimen for Intracranial Stenting or Flow-Diverter Treatment for Unruptured Cerebral Aneurysms: A Single-Center Cohort Study.

BACKGROUND AND PURPOSE: Ticagrelor is a novel P2Y12 antagonist, and little is known about its efficacy and safety in the endovascular treatment of aneurysms. This study evaluated the efficacy and safety of ticagrelor versus clopidogrel for stent-assisted coiling or flow-diversion treatment in patients with unruptured cerebral aneurysms. MATERIALS AND METHODS: From November 2003 to February 2019, two hundred one patients (mean age, 57.5 years; 156 women) with 233 unruptured aneurysms underwent stent-assisted coiling or flow-diversion treatment. All patients received antiplatelet therapy of aspirin plus clopidogrel (clopidogrel group, 121 patients with 140 aneurysms) or aspirin plus ticagrelor (ticagrelor group, 80 patients with 93 aneurysms). The clinical and radiologic data in each group were retrospectively reviewed and compared. RESULTS: Two hundred thirty-six procedures were performed, including stent-assisted coiling (n = 101) and flow diversion (n = 135). At 90 days, the primary outcome-a composite of any stroke and death-occurred in 9.9% of the clopidogrel group and 8.6% of the ticagrelor group (P = .822). Ischemic stroke occurred in 10 (7.0%) of the clopidogrel group and 7 (7.5%) of the ticagrelor group (P > .999). Disabling stroke occurred in 4 (2.8%) in the clopidogrel group and in 4 (4.3%) in the ticagrelor group (P = .716). Ninety-day death occurred in 3 (2.1%) in the clopidogrel group and 1 (1.1%) in the ticagrelor group (P > .999). Any bleeding at 90 days occurred in 13 (9.2%) in the clopidogrel group and 6 (6.5%) in the ticagrelor group (P = .479). CONCLUSIONS: Ticagrelor appears to be as effective and safe as clopidogrel in stent-assisted coiling or flow-diversion treatment for unruptured cerebral aneurysms.

Facial Venous Malformations Are Associated with Cerebral Developmental Venous Anomalies.

BACKGROUND AND PURPOSE: A number of studies have demonstrated the existence of segmental vascular disorders affecting soft tissues of the head and neck along with the intracranial vasculature. The purpose of this study was to determine whether there is an association between cerebral developmental venous anomalies and venous malformations of the face, head, and neck. MATERIALS AND METHODS: A consecutive series of patients with head and neck venous malformations who underwent MR imaging of the brain with postcontrast T1- or T2*-weighted imaging were included. Developmental venous anomaly prevalence in this patient population was compared with an age- and sex-matched control group without venous malformations at a ratio of 1:2. All images were interpreted by 2 neuroradiologists. Data were collected on venous malformation location, developmental venous anomaly location, developmental venous anomaly drainage pattern, and metameric location of venous malformations and developmental venous anomalies. Categoric variables were compared using χ2 tests. RESULTS: Forty-two patients with venous malformations were included. The mean age was 38.1 ± 11.1 years, and 78.6% of patients were female. The prevalence of developmental venous anomalies in this patient population was 28.6%. The control population of 84 patients had a mean age of 40.0 ± 5.9 years, and 78.6% of patients were female. The prevalence of developmental venous anomalies in this patient population was 9.5% (P = .01). In 83.3% of cases, developmental venous anomalies were ipsilateral to the venous malformation, and in 75% of cases, they involved the same metamere. CONCLUSIONS: Our case-control study demonstrated a significant association between brain developmental venous anomalies and superficial venous malformations. These findings suggest that there may be a similar pathophysiologic origin for these 2 entities.

Endovascular Management of Acute Stroke in the Elderly: A Systematic Review and Meta-Analysis.

BACKGROUND: Acute ischemic stroke occurs more frequently, presents with more severe symptoms, and has worse outcomes in elderly patients. The safety and efficacy of endovascular therapy for acute stroke in this age group has not been fully established. PURPOSE: We present the results of a systematic review and meta-analysis examining clinical, procedural, and radiologic outcomes of endovascular therapy for acute stroke in patients older than 80 years of age. DATA SOURCES: We searched PubMed, MEDLINE, and EMBASE from 1992 to week 35 of 2017 for studies evaluating endovascular therapy for acute stroke in the elderly. STUDY SELECTION: Two independent reviewers selected studies and abstracted data. The primary end point was good functional outcome at 3 months defined as modified Rankin Scale score of ≤2. DATA ANALYSIS: Data were analyzed using random-effects meta-analysis. DATA SYNTHESIS: Seventeen studies reporting on 860 patients were included. The rate of good functional outcome at 3 months was 27% (95% CI, 21%-32%). Mortality at 3 months was 34% (95% CI, 23%-44%). Successful recanalization was achieved in 78% of patients (95% CI, 72%-85%). Procedure-related complications occurred in 11% (95% CI, 4%-17%). The incidence of intracranial hemorrhage was 24% (95% CI, 15%-32%), and for symptomatic intracranial hemorrhage, it was 8% (95% CI, 5%-10%). The mean time to groin was 251 minutes (95% CI, 224-278 minutes). Procedure time was 99 minutes (95% CI, 67-131 minutes). LIMITATIONS: I2 values were above 50% for all outcomes, indicating substantial heterogeneity. CONCLUSIONS: Good functional recovery in octogenarians treated with endovascular therapy for acute stroke can be achieved in a high proportion of patients despite the higher incidence of comorbidity in this cohort. Outcomes are inferior to those reported for younger patients; however, endovascular therapy can allow at least 1 in 4 patients older than 80 years of age to regain independent function at 3 months. More research is required to improve patient selection in the elderly, but age should not be a discriminator when deciding to offer endovascular therapy for patients with acute stroke.

The venous distension sign: a diagnostic sign of intracranial hypotension at MR imaging of the brain.

BACKGROUND AND PURPOSE: Patients with intracranial hypotension (IH) demonstrate intracranial venous enlargement with a characteristic change in contour of the transverse sinus seen on routine T1-weighted sagittal imaging. In IH, the inferior margin of the midportion of the dominant transverse sinus acquires a distended convex appearance; we have termed this the venous distension sign (VDS). This is distinct from the normal appearance of this segment, which usually has a slightly concave or straight lower margin. This sign is introduced, and its performance as a test for the presence of this disease is evaluated. MATERIALS AND METHODS: The transverse sinuses on T1-weighted sagittal imaging of 15 patients with IH and 15 control patients were independently assessed in a blinded fashion by 3 readers for the presence of a VDS. A present or absent VDS was determined for each patient by each reader, and a consensus result for each patient was determined by unanimity or majority rule. RESULTS: Using the VDS, the readers correctly identified 93% (14 of 15) of the IH patients and similarly 93% (14 of 15) of the control patients. There was a high rate of agreement among the readers for the interpretation of the VDS (multirater kappa = 0.82). The overall sensitivity of the VDS for the diagnosis of intracranial hypotension was 94%. Specificity was also 94%. CONCLUSION: The VDS appears to be an accurate test for the presence or absence of IH and may be helpful in the evaluation of these patients.

High-Resolution Vessel Wall Magnetic Resonance Imaging in Angiogram-Negative Non-Perimesencephalic Subarachnoid Hemorrhage.

PURPOSE: Standard magnetic resonance imaging (MRI) rarely identifies the cause of hemorrhage in patients with an angiogram-negative, non-perimesencephalic subarachnoid hemorrhage (SAH). Yet up to 10 % of these patients have recurrent hemorrhage. The aim of the study was to explore the potential role of high-resolution contrast-enhanced 3-Tesla vessel wall-MRI in patients with angiogram-negative SAH. METHODS: We performed intracranial vessel wall-MRI of the circle of Willis using a 3-Tesla scanner in consecutive patients presenting with a spontaneous, angiogram-negative, non-perimesencephalic SAH. Vessel wall-MRI included T1-, T2-, and gadolinium-enhanced T1-weighted two-dimensional black-blood sequences in multiple planes (voxel size 0.4 × 0.4 × 2.0 mm). Two neuroradiologists independently scored abnormalities of the arterial wall. RESULTS: In all, 11 patients (mean age 59 years) underwent vessel wall-MRI. A total of seven patients had vessel wall abnormalities despite normal catheter angiography. Two patients had focal abnormalities contiguous with the outer margin of the basilar artery wall for which we considered a differential of ruptured blood blister aneurysm, thrombosed aneurysm, and loculated extramural blood from elsewhere. Two patients had arterial wall enhancement involving multiple arteries, possibly secondary to SAH. Three patients had arterial wall enhancement at sites of dural penetration, remote from the SAH, likely related to age and atherosclerotic risk factors. Vessel wall-MRI did not alter patient management in this cohort. CONCLUSION: Vessel wall-MRI showed abnormalities in seven patients with angiogram-negative SAH. These findings did not alter patient management, but the findings may be useful for other physicians who choose to perform vessel wall-MRI in this patient population.

Neuroimaging in the diagnosis of idiopathic intracranial hypertension.

Traditionally, the primary role of imaging in the diagnosis of idiopathic intracranial hypertension (IIH) has been to exclude other conditions that can cause increased intracranial pressure (ICP) and papilledema. Over the years multiple attempts have been made to define objective signs on cross-sectional imaging as well as on cerebral angiography that would actually identify IIH patients rather than only exclude other underlying conditions. There was also hope that mechanism-derived' imaging techniques such as magnetic resonance venography (MRV) and diffusion weighted imaging would potentially provide insight into the still unknown underlying etiology of this disease. It was recently shown in a double blind controlled study that flattening of the posterior aspect of the globe is the only sign on cross-sectional imaging that, if present, strongly suggests the diagnosis of IIH. In addition, evaluation of extra-luminal and intra-luminal narrowing of the transverse and sigmoid dural sinuses with contrast enhanced MRV using a simple grading system provides a highly sensitive and specific test for identifying patients with IIH. Unfortunately none of the imaging based studies published to date can explain the pathogenesis of IIH whether it be a primary vascular venous disorder causing the increase in ICP or rather the disorder itself secondarily affecting the cerebral veins.

Abnormal liver cholesteryl ester storage in a strain of golden hamsters. Possible model for studies on cholesterol metabolism.

Very high values of hepatic cholesteryl esters were found in a strain of golden hamsters isolated in our laboratory: 2 g/100 g in animals kept at 22 degrees C and more than 10 g/100 g in starved cold-adapted animals. The rate of incorporation of labelled mevalonate was not increased, but the esterification of the newly-synthetized cholesterol was markedly stimulated.

Cerebral arteriovenous fistulas induced by dural arteriovenous shunts.

Dural arteriovenous shunts and pial arteriovenous fistulas are uncommonly associated. Their etiology, pathogenesis, and natural history are still unclear and are likely different. We present three cases of high-flow dural arteriovenous shunts associated with pial arteriovenous fistulas and discuss their pathogenesis, anatomic association, and angioarchitecture. We propose that venous steal effect in the dural sinus secondary to the high-flow dural arteriovenous shunt induced the pial arteriovenous fistulas. Treatment of the high-flow dural arteriovenous shunts and the induced pial arteriovenous fistulas are discussed.

An extra-adrenal action of adrenocorticotrophin: physiological induction of lipolysis by secretion of adrenocorticotrophin in obese rabbits.

The effect of minor stressful stimuli (saline infusions or venepunctures) on lipid mobilization (estimated by plasma free fatty acids (FFA) and glycerol levels) was studied in two strains of conscious rabbits of various ages. Infusions of 0.9% (w/v) NaCl solution induced a prompt increase of FFA levels in naturally obese rabbits while this effect was absent in younger lighter animals. Administration of propranolol (a beta-adrenoceptor blocking drug) beforehand did not prevent lipid mobilization. Adipose tissue in vitro was completely unresponsive to the lipid mobilizing action of adrenaline. The initial output of ACTH induced by stressful stimuli was quickly followed by the increase in the plasma concentration of FFA. A highly significant correlation (r = 0.84 or 0.85; P less than 0.01) existed between plasma ACTH and FFA levels 30 and 60 min after the start of stress. Dexamethasone completely prevented lipid mobilization while adipose tissue in vivo and in vitro responded strongly to ACTH. Consequently the lack of response of plasma FFA concentrations in corticosteroid-treated rabbits seemed to be linked to the failure of the pituitary gland to mobilize ACTH rather than to the unresponsiveness of adipose tissue to the pituitary hormone. Our data indicate that in the rabbit, under conditions of stress, ACTH is of greater physiological importance than catecholamines in the control of lipolysis.

Endoscopic sphenoid sinus drainage in Lemierre syndrome.

Lemierre syndrome is a rare condition arising from an invasive oropharyngeal infection, which leads to septic thrombophlebitis of the internal jugular vein and multi-organ septic embolization. Intracranial complications are rare but serious, including subdural empyema, cavernous sinus thrombosis, and internal carotid artery aneurysms. We report a patient with Lemierre syndrome with multiple intracranial complications despite aggressive antimicrobial therapy. The patient eventually required transsphenoidal endoscopic drainage of the sphenoid sinus to help eradicate the infectious source. We postulate that in patients with Lemierre syndrome with evidence of infection in the paranasal sinuses, endoscopic sinus drainage can be an adjunct to antimicrobial therapy in achieving infection control.

Enhancing brain lesions after endovascular treatment of aneurysms.

Complications of endovascular therapy of aneurysms mainly include aneurysm rupture and thromboembolic events. The widespread use of MR imaging for follow-up of these patients revealed various nonvascular complications such as aseptic meningitis, hydrocephalus, and perianeurysmal brain edema. We present 7 patients from 5 different institutions that developed MR imaging-enhancing brain lesions after endovascular therapy of aneurysms, detected after a median time of 63 days. The number of lesions ranged from 4-46 (median of 10.5), sized 2-20 mm, and were mostly in the same vascular territory used for access. Three patients presented with symptoms attributable to these lesions. After a median follow-up of 21.5 months, the number of lesions increased in 2, was stable in 1, decreased in 3, and disappeared in 1. The imaging and clinical characteristics suggested a foreign body reaction. We could find no correlation to a specific device, but a possible source may be the generic hydrophilic coating.

CE-MRA for follow-up of aneurysms post stent-assisted coiling.

This study compared the accuracy of contrast-enhanced MR angiography (CE-MRA) to intra-arterial cerebral angiography (IA-DSA) for assessment of intracranial aneurysms after stent-assisted coiling and to check if the presence of a stent in the parent artery diminishes the accuracy of CE-MRA. Consecutive patients with cerebral aneurysms treated by stent-assisted coiling were evaluated retrospectively. Matching follow-up CE-MRA and IA-DSA were evaluated separately. Evaluation included the presence of aneurysmal remnant, patency and stenosis of parent artery. Twenty-seven patients with 28 aneurysms and 33 matched CE-MRA and IA-DSA studies were evaluated. Nineteen aneurysmal remnants were seen on CE-MRA and 16 on IA-DSA. CE-MRA diagnosed three aneurysmal remnants not appreciated on IA-DSA. Five other remnants were larger on CE-MRA than IA-DSA. None of the remnants were missed on CE-MRA. Parent arteries were patent on both modalities. CE-MRA showed false stenosis of the stented artery in six cases and exaggerated stenosis in two. In 18 cases, CE-MRA showed a short focal "pseudo-stenosis" where the stent's marker bands were located. This was noted whenever the stent's marker bands were located in an artery with luminal diameter ≤2 mm and was called "marker band effect". CE-MRA is an accurate technique for follow-up of aneurysms post stent-assisted coiling with excellent depiction of remnants in spite of the presence of a stent. Apparent stenosis of the stented parent artery on CE-MRA is often false or exaggerated. "Marker band effect" should be recognized as an artifact that appears when stent's marker bands are in a small artery.

Salvage of the carotid artery with covered stent after perforation with dialysis sheath. A case report.

We present a rare case of carotid tear caused by iatrogenic erroneous insertion of a dialysis sheath into the common carotid artery (CCA). This was treated by placement of a covered stent-graft in the CCA over the puncture site. This treatment achieved hemostasis while preserving the carotid artery with good outcome. The technical details are presented and the relevant literature regarding treatment of carotid blowout syndrome is discussed. This case suggests that placement of a covered stent-graft is a good option not only for the "usual" blowout syndrome due to head and neck tumors, but also for treatment of iatrogenic injury to the carotid artery.

Recanalization rates after endovascular coil embolization in a cohort of matched ruptured and unruptured cerebral aneurysms.

The aim of this study was to retrospectively assess the recanalization rate, factors associated with and time taken for recanalization to occur in a matched ruptured and unruptured aneurysm population that were treated with endovascular coiling.Ruptured and unruptured aneurysms treated between 2002 and 2007 were matched for aneurysm location, diameter and neck size. Recanalization rate, time to recanalize, re-treatment rate and clinical outcome were analysed. Ninety-eight matched ruptured and unruptured aneurysms (49 aneurysms in each group) were studied. 46.8% of aneurysms in the ruptured group achieved complete obliteration on the initial post treatment angiogram versus 34.7% in the unruptured group. The ruptured group had a higher rate of recanalization (40.4% versus 20.4%). 25.5% of aneurysms had significant recanalization in the ruptured group versus 6.1% in the unruptured group (p=0.009). The retreatment rate was higher in the ruptured group (21.3% versus 6%). Ruptured aneurysms took a shorter time to recanalize with a mean time of 5.3±3.8 months versus 12.4±7.7months (p=0.003). Multivariate logistic regression analysis found neck size (p=0.0098), wide neck morphology (p=0.0174), aneurysm diameter (p< 0.0001) and ruptured aneurysms (p=0.0372) were significant predictors of recanalization. The majority of patients in both groups had a good outcome with GOS=5 (85.7% and 83.7%) but two deaths occurred in the ruptured group.Ruptured and unruptured aneurysms showed significant differences in rate, degree and timing of recanalization, thus requiring different protocols for imaging follow-up post endovascular treatment. Earlier and more frequent imaging follow-up is recommended for ruptured aneurysms.

Osteogenesis imperfecta, multiple intra-abdominal arterial dissections and a ruptured dissecting-type intracranial aneurysm.

We describe an adult patient with a ruptured dissecting-type superior cerebellar artery aneurysm and known osteogenesis imperfecta. He was successfully treated with coil embolization and intentional parent vessel sacrifice. During his hospital admission, he also suffered from abdominal distension. An incidental note was made of multiple intra-abdominal arterial dissections. These were managed conservatively. We review the rare association of osteogenesis imperfecta and intracranial aneurysms, as well as discuss management implications.

Percutaneous sclerotherapy for facial venous malformations: subjective clinical and objective MR imaging follow-up results.

BACKGROUND AND PURPOSE: Venous malformations are the most common of all vascular anomalies, 40% of which are found in the head and neck. We discuss results of percutaneous sclerotherapy using bleomycin for facial VMs by using subjective clinical assessment and objective changes on MR imaging. MATERIALS AND METHODS: Thirty-seven patients with facial VMs were treated by percutaneous sclerotherapy with bleomycin. Of these, 31 patients with 32 lesions had pre- and posttreatment MR imaging. Each lesion received between 1 and 9 sclerotherapy sessions (average, 3.5). MR findings and clinical results of treatment were retrospectively reviewed. Clinical results were based on the physician's physical examination and interview of the patient; these were classified as worse, unchanged, or better. Objective results on MR imaging were classified as worse, no change, minor improvement (<50% decrease in size), marked improvement (>or=50% decrease), or cure. Objective and subjective results were compared. RESULTS: Twenty-one lesions showed objective improvement on MR imaging. Of these, 10 showed minor decrease in size and 11 showed marked decrease. Eleven lesions showed no change on MR imaging. No VMs were worse or completely cured. Subjectively, 29 patients and 30 clinicians thought that lesions improved. Four of 32 (12.5%) patients suffered minor transient complications. CONCLUSIONS: Percutaneous sclerotherapy by using bleomycin is a safe technique to objectively decrease size and subjectively alleviate symptoms of facial VMs. Subjective clinical improvement is not always associated with visual size reduction on MR imaging. Minimal size reduction or partial fibrosis of the lesion may be enough to achieve subjective clinical improvement.

Negative CT angiography findings in patients with spontaneous subarachnoid hemorrhage: When is digital subtraction angiography still needed?

BACKGROUND AND PURPOSE: CTA is becoming the frontline modality to reveal aneurysms in patients with SAH. However, in about 20% of SAH patients no aneurysm is found. In these cases, intra-arterial DSA is still performed. Our aim was to evaluate whether negative findings on CTA can reliably exclude aneurysms in patients with acute SAH. MATERIALS AND METHODS: We conducted a retrospective analysis of all negative findings on CTAs performed from 2005 to 2009 in patients with spontaneous SAH. Findings were compared with DSA. CTAs were performed with a 64-section multidetector row CT scanner. RESULTS: One hundred ninety-three patients with SAH and negative findings on CTA who underwent subsequent DSA were identified. The distribution of blood on unenhanced CT was the following: PMH in 93 patients, diffuse aneurysmal pattern in 50, no blood on CT (xanthochromic LP) in 32, and peripheral sulcal distribution in 18. All patients with PMH had negative findings on DSA. One patient with no blood on CT had vasculitis on DSA. Six of 18 (33%) patients with peripheral blood had vasculitis on DSA. Three of these were also diagnosed by CTA. All except 1 patient with diffuse aneurysmal blood had negative findings on DSA. One patient was diagnosed with an aneurysm on DSA (1/50, 0.5%). Repeat delayed DSA performed in 28 of these patients revealed a small aneurysm in 4 (14%). Five patients had a complication of DSA (2.6%); 1 was a clinical stroke (0.5%). CONCLUSIONS: In patients with SAH, negative CTA findings are reliable in ruling out aneurysms in the PMH pattern or no blood on CT. DSA is indicated in the diffuse aneurysmal pattern of SAH, and repeat delayed DSA is required if the initial DSA findings are negative. When the blood is peripheral, CTA should be scrutinized for vasculitis and DSA is recommended for confirmation.

Bare, bio-active and hydrogel-coated coils for endovascular treatment of experimentally induced aneurysms. Long-term histological and scanning electron microscopy results.

Endovascular treatments of cerebral aneurysms with bare platinum coils have a higher rate of recurrence compared to surgical clipping. This may be related to failed vessel wall reconstruction since histological and scanning electron microscopy results following embolization failed to demonstrate neoendothelialization over the aneurysm neck. The present study tried to elucidate whether the use of modified coils resulted in a better rate of reconstructing the vessel wall over the aneurysm neck in experimental aneurysms. Aneurysms were created in 20 rabbits by intraluminal elastase incubation of the common carotid artery. Five animals each were assigned to the following groups: untreated, bare platinum coils, bioactive coils with polyglycolic/polylactic acid coating, and hydrogel-coated platinum coils. After 12 months, angiography, histology and scanning electron microscopy was performed. No neoendothelial layer was visualized in the bioactive and bare coil groups with a tendency to an increased layering of fibroblasts along the bioactive coils at the aneurysm fundus. However, at the aneurysm neck perfused clefts were present and although a thin fibrinous layer was present over some coils, no bridging neointimal or neoendothial layer was noted over different coils. Following loose Hydrogel coiling, a complete obliteration of the aneurysm was present with neoendothelialization present over different coil loops. The study demonstrates that with surface coil modifications complete and stable aneurysm obliteration may become possible. A smooth and dense surface over the aneurysm neck may be necessary for endothelial cells to bridge the aneurysm neck and to lead to vessel wall reconstruction.