Internal Carotid Artery Aneurysm Research Articles

A synthetic model simulator for intracranial aneurysm clipping: validation of the UpSurgeOn AneurysmBox.

In recent decades, the rise of endovascular management of aneurysms has led to a significant decline in operative training for surgical aneurysm clipping. Simulation has the potential to bridge this gap and benchtop synthetic simulators aim to combine the best of both anatomical realism and haptic feedback. The aim of this study was to validate a synthetic benchtop simulator for aneurysm clipping (AneurysmBox, UpSurgeOn). Expert and novice surgeons from multiple neurosurgical centres were asked to clip a terminal internal carotid artery aneurysm using the AneurysmBox. Face and content validity were evaluated using Likert scales by asking experts to complete a post-task questionnaire. Construct validity was evaluated by comparing expert and novice performance using the modified Objective Structured Assessment of Technical Skills (mOSATS), developing a curriculum-derived assessment of Specific Technical Skills (STS), and measuring the forces exerted using a force-sensitive glove. Ten experts and eighteen novices completed the task. Most experts agreed that the brain looked realistic (8/10), but far fewer agreed that the brain felt realistic (2/10). Half the expert participants (5/10) agreed that the aneurysm clip application task was realistic. When compared to novices, experts had a significantly higher median mOSATS (27 vs. 14.5; p < 0.01) and STS score (18 vs. 9; p < 0.01); the STS score was strongly correlated with the previously validated mOSATS score (p < 0.01). Overall, there was a trend towards experts exerting a lower median force than novices, however, these differences were not statistically significant (3.8 N vs. 4.0 N; p = 0.77). Suggested improvements for the model included reduced stiffness and the addition of cerebrospinal fluid (CSF) and arachnoid mater. At present, the AneurysmBox has equivocal face and content validity, and future versions may benefit from materials that allow for improved haptic feedback. Nonetheless, it has good construct validity, suggesting it is a promising adjunct to training.

No Delayed Ruptures on Long-Term Follow-Up of a Case Series of Persistently Filling Saccular Internal Carotid Artery Aneurysms After Flow Diversion With the Pipeline Embolization Device.

Flow diversion of intracranial aneurysms results in high occlusion rates. However, 10% to 20% remain persistently filling at 1 year. Often, these are retreated, but benefits of retreatment are not well established. A better understanding of the long-term rupture risk of persistently filling aneurysms after flow diversion is needed. Our institutional database of 974 flow diversion cases was queried for persistently filling saccular aneurysms of the clinoidal, ophthalmic, and communicating segments of the internal carotid artery treated with the pipeline embolization device (PED, Medtronic). Persistent filling was defined as continued flow into the aneurysm on 1 year catheter angiogram. The clinical record was queried for retreatments and delayed ruptures. Clinical follow-up was required for at least 2 years. Ninety-four persistent aneurysms were identified. The average untreated aneurysm size was 5.6 mm. A branch vessel originated separately in 55% of cases from the body of the aneurysm in 10.6% of cases and from the neck in 34% of cases. Eighteen percent of aneurysms demonstrated >95% filling at 1 year, and 61% were filling 5% to 95% of their original size. The mean follow-up time was 4.9 years, including 41 cases with >5 years. No retreatment was undertaken in 91.5% of aneurysms. There were no cases of delayed subarachnoid hemorrhage. Among saccular internal carotid artery aneurysms treated with PED that demonstrated persistent aneurysm filling at 1 year, there were no instances of delayed rupture on long-term follow-up. These data suggest that observation may be appropriate for continued aneurysm filling at least in the first several years after PED placement.

Difference in the cumulative incidence of aneurysmal occlusion by Flow Re-direction Endoluminal Device and Pipeline Embolization Device in the treatment of unruptured internal carotid artery aneurysms: a propensity score-matched cohort study.

The introduction of flow diverters (FDs) has represented a paradigm shift in the management of unruptured cerebral aneurysms (UCA). Flow Re-direction Endoluminal Devices (FREDs) and Pipeline Embolization Devices (PEDs) have gained widespread popularity. We aimed to investigate the cumulative incidence of aneurysm occlusion. A total of 195 patients with 199 UCAs were analyzed retrospectively. The outcomes were aneurysmal occlusion during the follow-up, a modified Rankin Scale score of 0-2 at 90days, additional treatment, major stroke, and steno-occlusive events of FD. Propensity score-matched analysis was performed, controlling for age, sex, aneurysmal size, and location of the internal carotid artery (ICA) aneurysm. Non-ICA aneurysms were excluded from matching. During the follow-up period (median, 366days), complete and satisfactory aneurysmal occlusions were observed in 128 (68%) and 148 (78%) of 189 UCAs in the unmatched cohort. The 142 (71 each) propensity score-matched cohort was complied. The FRED group had a higher cumulative incidence of ICA aneurysm occlusion (complete: HR 2.7, 95% CI 1.4-5.1, p = 0.0025; satisfactory: HR 2.4, 95% CI 1.1-5.2, p = 0.025). The proportion of additional treatment was significantly smaller in the FRED group (OR 0.077, 95% CI 0.010-0.57, p = 0.0007). Other outcomes showed no significant differences. Propensity score-matched analysis indicated that FRED might have a higher cumulative incidence of aneurysmal occlusion in the treatment of unruptured ICA aneurysms. Whether a cumulative incidence of aneurysmal occlusion may differ by the type of FDs warrants further investigation.

Pipeline embolization device versus Atlas stent assisted coiling for intracranial aneurysm treatment: a retrospective, propensity score matched study with a focus on midterm outcomes and hospital costs

BackgroundStent assisted coiling (SAC) and flow diverters (FDs) are common endovascular treatments for wide necked cerebral aneurysms, but studies comparing the new generation Atlas SAC and FDs are scarce. We...

Crisis parciales como presentación atípica de aneurisma gigante

Los aneurismas gigantes suelen manifestarse en forma de hemorragia subaracnoidea o cefalea. La presentación clínica de un aneurisma gigante intracraneal como epilepsia parcial es inusual, como lo indican los pocos casos recogidos en la literatura.&#x0D; Se presenta el caso de un aneurisma gigante intracraneal de arteria carótida interna derecha, que debuta con crisis focales del lóbulo temporal, manteniéndose sin otra manifestación a lo largo de años a pesar de las llamativas dimensiones.

Letter: Transradial Flow-Diverting Stent Placement Through an Arteria Lusoria: 2-Dimensional Operative Video.

To the Editor: We read with great interest the article “Transradial Flow-Diverting Stent Placement Through an Arteria Lusoria: 2-Dimensional Operative Video” by Hackett et al.1 The authors present a case of a patient with an arteria lusoria who received effective flow-diverting stent therapy for a large left internal carotid artery (ICA) aneurysm using a large bore guide catheter through right transradial access (TRA). Diagnostic angiography showed that the left ICA could be accessed through the right TRA. A 6F radial sheath was introduced into the right radial artery, and the sheath was then exchanged over a 0.035″ guidewire for an 8F 90-cm guide catheter (Infinity; Stryker Neurovascular). After navigating a 5F 130-cm Simmons catheter into the left common carotid artery through the arteria lusoria, the 8F guide catheter was delivered into the left ICA using the telescoping technique. The large left ICA-ophthalmic artery aneurysm was successfully treated with a pipeline embolization device (Medtronic). The importance of evaluating transradial diagnostic angiography to determine whether a catheter system can safely track into the target supra-aortic vessels is critical for successful transradial neurointervention in patients with arteria lusoria, and we wholeheartedly concur with the authors' conclusion on this point. Cannulation into the supra-aortic vessels through right TRA can be extremely challenging in patients with arteria lusoria because of unfavorable catheter trajectory.2 In addition, the right TRA can cause fatal arteria lusoria dissection.3 Therefore, transfemoral access is frequently employed as first-line access if neurointerventionalists encounter arteria lusoria.2 Previous study reported that left TRA is a technically feasible alternative in neurointerventions for patients with arteria lusoria.4 Nevertheless, a guide catheter may result in a failed TRA that necessitates a crossover to transfemoral access because of a failed cannulation, a kinked catheter, or an unstable system. We have used transradial access as the first-line access for neurointerventions.5-18 The first-line TRA using a 6F preshaped Simmons guiding sheath (outer diameter, 2.70 mm; inner diameter, 0.088″; usable length, 90 cm; 6F Axcelguide Stiff-J; Medikit) offers a large bore working channel and a high procedural success rate without catheter kinking or system instability even in patients with an unfavorable steep supra-aortic take-off.5-7,13 The 6F Simmons guiding sheath is fully engaged into the target common carotid artery with a pull-back maneuver (the pull-back technique) after reforming the Simmons curve within the ascending aorta. The Simmons curve can be reformed by anchoring the 6F Simmons guiding sheath to the descending aorta (the descending aorta anchoring technique) or contralateral subclavian artery (the subclavian artery anchoring technique) through the left TRA. Transradial carotid cannulation with the pull-back technique is technically simple and promising. As a result, left TRA with the 6F Simmons guiding sheath can be a beneficial treatment choice for performing anterior circulation procedures in patients with arteria lusoria. Finally, we would like to express our appreciation to the authors for their interesting article that advances the transradial neurointerventional method.

Combined Double-Barrel Superficial Temporal Artery to M4 Bypass and Parent Artery Occlusion for the Treatment of Complex Intracranial Aneurysms in Internal Carotid Artery and Middle Cerebral Artery: A Retrospective Case Series.

Very little research has been conducted to assess the efficacy of combined double-barrel superficial temporal artery (STA) to M4 bypass and parent artery occlusion (PAO) in the treatment of complex intracranial aneurysms. To determine whether this operation could become a reasonable flow replacement therapy and have longer-term benefits. A series of double-barrel STA-M4 bypasses performed between 2016 and 2021 were reviewed. Preoperative digital subtraction angiography (DSA), computed tomography angiography (CTA), computed tomography perfusion (CTP), and balloon test occlusion were routinely performed for a thorough evaluation of individual benefits and risks. After bypass, the proximal end of the parent artery was permanently occluded with the coil. Augmentation and patency of STA were reassessed by postoperative DSA, CTA, and CTP. The blood flow volume of STA was measured by ultrasound at admission and a 3-month follow-up. This study included 12 consecutive patients (5 males, 7 females) who successfully underwent double-barrel STA-M4 bypass, including 8 complex aneurysms in the internal carotid artery (ICA) and 4 in the middle cerebral artery (MCA). Postoperative angiography and CTP suggested that all the STAs were patent, and there was a significant improvement in perfusion after the operation ( P < .05). Ultrasonic measurement at the 3-month follow-up showed that the blood flow provided by STA was 76.3 to 190.5 mL/min. Postoperative ischemia was found in 1 patient, but she recovered after treatment. Double-barrel STA to M4 bypass can provide adequate flow for the parent artery area, which may be a reasonable flow replacement therapy for some complex intracranial aneurysms in ICA and MCA.

Endoscope-assisted microsurgical clipping and reduction of post-clipping cerebral infarction: historical comparison using diffusion-weighted images

Endoscopic assistance for aneurysm clipping and its possible benefits have been suggested in previous studies, but its clinical significance has not been fully elucidated. This study aimed to present the efficacy of endoscopy-assisted clipping in reducing post-clipping cerebral infarction (PCI) and clinical outcomes via a historical comparison of patients in our institution from January 2020 to March 2022. A total of 348 patients were included, 189 of whom underwent endoscope-assisted clipping. The overall incidence of PCI was 10.9% (n = 38); it was 15.7% (n = 25) before applying endoscopic assistance and decreased to 6.9% (n = 13) after endoscope application (p = 0.010). The application of a temporary clip (odds ratio [OR]: 2.673, 95% confidence interval [CI]: 1.291-5.536), history of hypertension (OR: 2.176, 95% CI: 0.897-5.279), history of diabetes mellitus (OR: 2.530, 95% CI: 1.079-5.932), and current smoker (OR: 3.553, 95% CI: 1.288-9.802) were independent risk factors of PCI, whereas endoscopic assistance was an independent inverse risk factor (OR: 0.387, 95% CI: 0.182-0.823). Compared to the location of the unruptured intracranial aneurysms, internal carotid artery aneurysms showed a significant decrease in the incidence of PCI (5.8% vs. 22.9%, p = 0.019). In terms of clinical outcomes, PCI was a significant risk factor for longer admission duration, intensive care unit stay, and poor clinical outcomes. However, endoscopic assistance itself was not a significant risk factor for clinical outcomes on the 45-day modified Rankin Scale. In this study, we noted the clinical significance of endoscope-assisted clipping in preventing PCI. These findings could reduce the incidence of PCI and improve the understanding of its mechanisms of action. However, a larger and longer-term study is required to evaluate the benefits of endoscopy on clinical outcomes.

Reduction of rupture risk in ICA aneurysms by endovascular techniques of coiling and stent: numerical study

The initiation, growth, and rupture of cerebral aneurysms are directly associated with Hemodynamic factors. This report tries to disclose effects of endovascular technique (coiling and stenting) on the quantitative intra-aneurysmal hemodynamic and the rupture of cerebral aneurysms. In this paper, Computational Fluid Dynamic are done to investigate and compare blood hemodynamic inside aneurysm under effects of deformation (due to stent) and coiling of aneurysm. The blood stream inside the sac of aneurysm as well as pressure and OSI distribution on the aneurysm wall are compared in nine cases and results of two distinctive cases are compared and reported. Obtained results specifies that the mean WSS is reduced up to 20% via coiling of the aneurysm while the deformation of the aneurysm (applying stent) could reduce the mean WSS up to 71%. In addition, comparison of the blood hemodynamic shows that the blood bifurcation occurs in the dome of aneurysm when endovascular technique for the treatment is not applied. It is found that the bifurcation occurs at ostium section when ICA aneurysm is deformed by the application of stent. The impacts of coiling are mainly limited since the blood flow entrance is not limited in this technique and WSS is not reduced substantial. However, usage of stent deforms the aneurysm angle with the orientation of parent vessel and this reduces blood velocity at entrance of the ostium and consequently, WSS is decreased when deformation of the aneurysm fully occurs. These qualitative procedures provide a preliminary idea for more profound quantitative examination intended for assigning aneurysm risk of upcoming rupture.

Transient Cortical Blindness Following Cerebral Angiography: A Case Report (P2-5.015)

<h3>Objective:</h3> We would like to report a case of Transient cortical blindness following cerebral angiography <h3>Background:</h3> Transient cortical blindness (TCB) is a rare complication following cerebral angiography. Its pathophysiology remains uncertain. We would like to report a case of TCB in a patient during follow up cerebral angiogram for post coil embolization of left internal carotid aneurysm. <h3>Design/Methods:</h3> 50-year-old woman with history of hypertension presents with bilateral vision loss during follow up cerebral angiography for ruptured left internal carotid artery aneurysm status post coiling. This was associated with headache, nausea, and emesis. No associated neurologic deficits. Review of symptoms was otherwise negative. CT Head and CTA showed no acute abnormalities. MRI done on admission showed no evidence of abnormalities. Ophthalmology saw the patient and exam was unrevealing. After 24 hours her vision gradually improved and was back to baseline after 48 hours with no intervention. <h3>Results:</h3> Transient Cortical Blindness is a rare but dramatic complication of cerebral angiogram. It is characterized by loss of perceived vision, normal fundi, normal papillary reflexes, and intact extraocular movements. Symptoms can occur at the start of the cerebral angiography procedure or until serval hours after. The recovery of normal vision may start within the first few hours, but may take as long as 5 days. Two hypothesis exist: could be due to a neurotoxic effect of contrast agent causing osmotic disruption of blood-brain barrier or could be the result of posterior reversible leukoencephalopathy syndrome leading to perivascular edema. There is no known treatment known to improve the condition. <h3>Conclusions:</h3> In summary, we reported a case of TCB following vertebral angiography, a rare but dramatic complication of cerebral angiography. Radiologists and clinicians should be aware of this complication. When it occurs, one should reassure the patient about the excellent prognosis of this condition. <b>Disclosure:</b> Dr. Gomez has nothing to disclose. Dr. Harris has nothing to disclose.

Widespread Aneurysms Secondary to Myosin Light-Chain Kinase Gene Mutation Leading to Multifocal Right Hemispheric Stroke (P3-5.001)

<h3>Objective:</h3> Familiarize providers with the presence of the Myosin Light-Chain Kinase (MYLK) and the possible vascular manifestations in individuals carrying this autosomal dominant gene mutation. <h3>Background:</h3> Myosin Light-Chain Kinase is a ubiquitously expressed kinase involved in the physiological contraction of smooth muscle cells within hollow organs. Variations in the Myosin Light-Chain Kinase (MYLK) gene lead to decrease in phosphorylation of 20kDa regulatory light-chain leading to a reduction in smooth muscle contractile function. MYLK gene mutations have been associated with autosomal dominant thoracic aortic aneurysms and dissections, however there are limited studies mentioning the involvement of other vascular structures containing these dysfunctional smooth muscle cells. In this report, we present a case of a 43-year-old individual who presented to the hospital for quadrantanopia, hearing loss and headache who was subsequently found to have an acute stroke of multiple foci involving the right ACA and MCA territories. Past medical history was significant for hemochromatosis, early onset coronary artery disease in self and close family members. Etiology workup revealed a right internal carotid artery aneurysm measuring 10cm. Complains of abdominal pain led to imaging revealing focal dissection of the abdominal aorta, a right common iliac artery 2.3cm aneurysm as well as a proximal celiac artery 1.7cm aneurysm. On outpatient genetic testing, the patient was found to be a carrier of the MYLK (p.Val509Met) gene mutation; variance was of unclear significance, however familial thoracic aneurysms/dissections have been reported in the Clinical Variance Database. The patient has since been managed with dual anti-platelet therapy and was instructed to follow closely with neurological and vascular surgery for close monitoring. <h3>Design/Methods:</h3> NA <h3>Results:</h3> NA <h3>Conclusions:</h3> This case highlights the MYLK gene mutation and its possible relationship with widespread malformations in the carotid, celiac, and mesenteric vasculature to familiarize practitioners with manifestations and clinical sequelae of individuals affected with this gene. <b>Disclosure:</b> Dr. Hamzoian has nothing to disclose. Dr. Abdelmasih has nothing to disclose. Dr. Ditamo has nothing to disclose. Dr. Kahila has nothing to disclose.

Multi-angled simultaneous biplane High-Speed Angiography (HSA) of patient-specific 3D-printed aneurysm phantoms using 1000 fps CdTe Photon-Counting Detectors (PCD's).

1000 fps HSA enables visualization of flow details, which may be important in accurately guiding interventional procedures; however, single-plane imaging may lack clear visualization of vessel geometry and flow detail. The previously presented high-speed orthogonal biplane imaging may overcome these limitations but may still result in foreshortening of vessel morphology. In certain morphologies, acquiring two non-orthogonal biplane projections at multiple angles can provide better flow detail rather than a standard orthogonal biplane acquisition. Flow studies of aneurysm models were performed, where simultaneous biplane acquisitions at various angles separating the two detector views allowed for better evaluation of morphology and flow. 3D-printed, patient-specific internal carotid artery aneurysm models were imaged with various non-orthogonal angles between the two high-speed photon-counting detectors (7.5 cm x 5 cm FOV) to provide frame-correlated simultaneous 1000-fps image sequences. Fluid dynamics were visualized in multi-angled planes of each model using automated injections of iodine contrast media. The resulting dual simultaneous frame-correlated 1000-fps acquisitions from multiple planes of each aneurysm model provided improved visualization of complex aneurysm geometries and flow streamlines. Multi-angled biplane acquisitions with frame correlation allows for further understanding of aneurysm morphology and flow details: additionally, the ability to recover fluid dynamics at depth enables accurate analysis of 3D flow streamlines, and it is expected that multiple-planar views will enable better volumetric flow visualization and quantification. Such better visualization has the potential to improve interventional procedures.

Determining 3D Distributions of Pulsatile Blood Flow Using Orthogonal Simultaneous Biplane High-Speed Angiography (SB-HSA) with 1000 fps CdTe Photon Counting Detectors for 3D X-ray Particle Image Velocimetry (3D-XPIV) compared to Results Using Computational Fluid Dynamics (CFD).

3D hemodynamic distributions are useful for the diagnosis and treatment of aneurysms. Detailed blood-flow patterns and derived velocity maps can be obtained using 1000 fps High Speed Angiography (HSA). The novel orthogonal Simultaneous Biplane High-Speed Angiography (SB-HSA) system enables flow information to be quantified in multiple planes, and with additional components of flow at depth, accurate 3D flow distributions are available. Computational Fluid Dynamics (CFD) is the current standard for derivation of volumetric flow distributions, but obtaining solution convergence is computationally expensive and time intensive. More importantly, matching in-vivo boundary conditions is non-trivial. Therefore, an experimentally derived 3D flow distribution method could offer realistic results with less computation time. Using SB-HSA image sequences, 3D X-Ray Particle Image Velocimetry (3D-XPIV) was explored as a new method for assessing 3D flow. 3D-XPIV was demonstrated using an in-vitro setup, where a patient-specific internal carotid artery aneurysm model was attached to a flow loop, and an automated injection of iodinated microspheres was used as a flow tracer. Two 1000 fps photon-counting detectors were placed orthogonally with the aneurysm model in the FOV of both planes. Frame-synchronization of the two detectors made correlation of single-particle velocity components at a given timepoint possible. With frame-rates of 1000 fps, small particle displacements between frames resolved realistic time varying flow, where accurate velocity distributions depended on near-instantaneous velocities. 3D-XPIV velocity distributions were compared to CFD velocity distributions, where the simulation boundary conditions matched the in-vitro setup. Results showed similar velocity distributions between CFD and 3D-XPIV.

Comparison of pulsatile flow dynamics before and after endovascular intervention in 3D-printed patient-specific internal carotid artery aneurysm models using 1000 fps photon-counting detectors for Simultaneous Biplane High Speed Angiography (SB-HSA).

A significant challenge regarding the treatment of aneurysms is the variability in morphology and analysis of abnormal flow. With conventional DSA, low frame rates limit the flow information available to clinicians at the time of the vascular intervention. With 1000 fps High-Speed Angiography (HSA), high frame rates enable flow details to be better resolved for endovascular interventional guidance. The purpose of this work is to demonstrate how 1000 fps biplane-HSA can be used to differentiate flow features, such as vortex formation and endoleaks, amongst patient-specific internal carotid artery aneurysm phantoms pre- and post-endovascular intervention using an in-vitro flow setup. The aneurysm phantoms were attached to a flow loop configured to a carotid waveform, with automated injections of contrast media. Simultaneous Biplane High-Speed Angiographic (SB- HSA) acquisitions were obtained at 1000 fps using two photon-counting detectors with the respective aneurysm and inflow/ outflow vasculature in the FOV. After x-rays were turned on, the detector acquisitions occurred simultaneously, during which iodine contrast was injected at a continuous rate. A pipeline stent was then deployed to divert flow from the aneurysm, and image sequences were once again acquired using the same parameters. Optical Flow, an algorithm that calculates velocity based on spatial-temporal intensity changes between pixels, was used to derive velocity distributions from HSA image sequences. Both the image sequences and velocity distributions indicate detailed changes in flow features amongst the aneurysms before and after deployment of the interventional device. SB-HSA can provide detailed flow analysis, including streamline and velocity changes, which may be beneficial for interventional guidance.

Combined Transarterial and Inferior Ophthalmic Vein Approach to a Direct Carotid-Cavernous Fistula: Technical Note

We describe our rescue technique for direct puncture of the inferior ophthalmic vein (IOV) for transvenous access of a direct, high-flow carotid-cavernous fistula (CCF). The CCF was caused by rupture of a large internal carotid artery aneurysm. Aneurysm and fistula embolization solely via the transarterial approach did not appear promising due to partial aneurysm thrombosis. Also, transvenous access via the facial vein failed due to extensive vessel tortuosity. Instead, the engorged and arterialized IOV was accessed by direct puncture with an 18-gauge venous cannula. After a small skin incision of the medial aspect of the lower eyelid and further transseptal puncture, the cannula was advanced stepwise between the maxillary bone and the bulbus oculi and below the medial rectus muscle to the IOV under repeated biplane roadmap guidance in 2 planes. Thereafter, the fistula and the aneurysm dome could be embolized with coils via a low-profile microcatheter. Hereby, a protective flow diverter was implanted via the arterial route into the internal carotid artery to seal the parent artery, prevent coil protrusion, and ensure permanent aneurysm occlusion. At 1-month follow-up, the aneurysm and CCF were completely occluded. Direct puncture of the IOV represents a feasible and minimally invasive approach for venous CCF access. The proposed method needs to be validated by further reports.

Endovascular treatment strategies and a new classification for multiple aneurysms of the ipsilateral ophthalmic segment of the internal carotid artery

ObjectiveAneurysms occurring in the ophthalmic segment (C6) of the internal carotid artery (ICA) have complex anatomy. This poses a challenge for the use of traditional open surgery, which is gradually being replaced by endovascular treatment (EVT). However, multiple aneurysm (MA) EVT, especially in MAs occurring ipsilaterally, has not been specifically described or discussed. The present study aimed to propose a more concise clinical classification standard for ipsilateral C6 ICA MAs and report on the clinical experience with EVT. MethodsThe cases of 18 patients with ipsilateral C6 ICA MAs treated with EVT were retrospectively reviewed. The treatment results and procedure-related complications were recorded, and clinical and angiographic follow-ups were performed at least six months after surgery. ResultsA total of 38 ipsilateral C6 ICA aneurysms were treated during the study period and classified into four main types and six total subtypes based on anatomical features. There was a failure to coil through the stent in one aneurysm, while the remaining 37 were successfully treated using various EVT methods. Of these, 36 were completely concluded. One aneurysm had a size reduction, and one had no changes during the angiographic follow-up. All Tubridge flow diverter stents were patent. All patients achieved satisfactory clinical outcomes and were independent at the final follow-up. ConclusionEVT may be safe and feasible for the treatment of C6 ICA MAs. Traditional stent-assisted coiling methods, the Willis covered stent, and the double-layered low-profile visualized intraluminal support stent all achieved favorable results. The flow diverter stent is also considered a safe and efficient option for selected aneurysms, but the visual deficit risk should be considered. The present study introduces a new EVT classification option based on the anatomical features of an aneurysm.

348 Risk of Rupture and Treatment Outcomes of Giant Pediatric Aneurysms: Multi-Institutional Case Series and Meta-Meta-Analysis

INTRODUCTION: Giant pediatric aneurysms are vascular malformations that can cause significant neurologic morbidity and mortality. Their rarity has precluded large cohort studies to inform their management. METHODS: Multi-institutional cohort study of cases from Boston Children’s Hospital (BCH) and the Barrow Neurologic Institute (BNI) along with systematic review and meta-analysis of previously reported cases. RESULTS: A total of 15 patients were included in the multi-institutional cohort, and an additional 88 patients were included from 14 series to yield 103 patients within the meta-analysis. Amongst the BCH patients, male sex was associated with giant size (OR .2; 95% CI 1.2-162.0).The most common aneurysm locations were in the MCA (38%), ICA (25%), vertebral artery (VA; 11%), and VBJ (8%). Within 69 reports containing radiographic data within the meta-analysis, 38% of aneurysms were saccular. Twenty-eight cases presented with rupture (28%). 0% of cavernous ICA aneurysms, 26% of other anterior circulation aneurysms, and 44% of posterior circulation aneurysms presented with rupture. Increasing age (OR 1.2; 95% CI 1.0-1.4) and saccular morphology (OR 5.3, 95% CI 1.5-18.9) were associated with presentation with rupture, while posterior location trended towards an association (OR 3.1, 95% CI 0.9-11.0). The majority of cases in the systematic review were treated (97%) rather than observed (3%). Endovascular and open treatments were utilized in 40 and 56% of cases. Survival was 97% for unruptured aneurysms and 82% for ruptured aneurysms. A favorable neurologic outcome occurred in 80% of unruptured cases and 54% of ruptured cases. Unruptured presentation (OR 3.7, 95% CI 1.3-11.1) and endovascular treatment modality were associated with a favorable outcome (OR 5.0; 95% CI 1.6-15.8). CONCLUSIONS: Giant pediatric aneurysms are unlikely to be discovered incidentally and often merit treatment. Increasing age and saccular morphology are r predict rupture, and should elevate the concern for semi-urgent treatment.

565 Delayed Rupture Risk of Persistently Filling Saccular ICA Aneurysms Following Flow Diversion with the Pipeline Embolization Device

INTRODUCTION: Flow diversion of intracranial aneurysms results in high occlusion rates. However, 10-20% of aneurysms remain persistently filling on one year angiography. Often, these are retreated, but risks and benefits of retreatment are not well established. Calculating benefit requires a better understanding of rupture risk of persistently filling flow diverted aneurysms, which is not sufficiently established. METHODS: Our single institution database of 1000 flow diversion cases was queried for persistently filling saccular aneurysms of the clinoidal, ophthalmic, and communicating segments of the internal carotid artery treated with Pipeline Embolization Device or Pipeline Flex. Persistent filling was defined as continued contrast flow into the aneurysm on catheter angiogram one year after treatment. The clinical record was queried for occurrences of retreatment and delayed subarachnoid hemorrhage. Only cases with at least two years of follow up were included. RESULTS: Ninety-four persistent aneurysms were identified. The average size was 6 mm. The branch vessel originated separately from the aneurysm in 55% of cases, from the body of the aneurysm in 10.6% of cases, and from the neck in 34% of cases. Eighteen percent of aneurysms demonstrated &gt;95% filling at one year and 61% were filling 5-95% of their original size. Average follow up time was 4.9 years, including 23 cases with &gt;5 years follow up. No retreatment was undertaken in 91.5% of aneurysms. There were no cases of delayed subarachnoid hemorrhage. CONCLUSIONS: In our cohort of saccular ICA aneurysms treated with Pipeline flow diversion that demonstrated persistent aneurysm filling at one year, there were no instances of delayed rupture during the study period. This data suggests that observation may be appropriate for continued aneurysm filling at least in the first several years following Pipeline placement.

Will improved neuroradiology facilities debunk the reported rarity of intracranial aneurysms in Sub-Saharan Africa?

Intracranial aneurysms (IAN) are rare in the Sub-Saharan Africa unlike other parts of the world. The debate is whether the low frequency might be apparent because of the scarcity of advanced neuroimaging services, or real. This study investigated if improved imaging facilities would debunk the rarity of IAN in our subregion. This is a retrospective cohort study of prospectively recorded data of patients with subarachnoid hemorrhage (SAH) and IAN managed over 19 years (2003-2021), at the study center with a catchment population of over 47 million. The center witnessed progressive improvements in neuroimaging facilities: 2-Slice, 8-slice, and 64-slice computed tomography (CT) and 0.35T, 1.5T magnetic resonance imaging (MRI) during the period. There were 241 cases of SAH, but only 166 aneurysms were confirmed in 158 patients. Between 2003 and 2008, only 27 IAN patients (4.5 IAN/year) were diagnosed. After introduction of CT angiography/magnetic resonance angiography MRA using 8-slice CT/0.35T magnetic resonance imaging (MRI), between 2009 and 2014, the frequency of IAN increased to 8/year. Between 2015 and 2018 after installation of a 64-slice CT in 2014, the IAN remained the same (8/year). MRI 1.5T was added in 2018, the frequency doubled to 17 cases/year. The females were more (67.7%), the mean age was 46.3 years, but peak incidence was the sixth decade. Internal carotid artery aneurysms including posterior communicating artery were the most common (43%) followed by ACA with anterior communicating artery (24%) and middle cerebral artery (20%). Multiple aneurysms were seen in ten patients. Improved neuroimaging between 2003 and 2021 did not debunk the rarity of IAN in our region.

180-degre carotid bifurcation with an internal carotid artery aneurysm.

Internal carotid artery (ICA) aneurysm is a rare pathology. In the clinical case we present, the patient had an ICA aneurysm as well as a rare anatomical variant of the carotid bifurcation. We present the case of a 45year old man, who had two episodes of TIA revealed by loss of mind. Computed tomography revealed the fusiform aneurysm of a left ICA in the first segment with maximal diameter of 16mm. There were no thrombotic mass in the dilated area. The carotid bifurcation angle was 180 degree. Although the aneurysm did not contain a thrombus mass, it was considered the source of the TIA because of turbulent blood flow. Distal and proximal ligation was performed. A 5-cm long graft from the great saphenous vein was used for ICA revascularization from common carotid artery. In our case, geometry of carotid bifurcation may have contributed to the ICA aneurysm, although there is no evidence for this correlation.