Giant Intracranial Aneurysms Research Articles

A systematic review of pipeline embolization device for giant intracranial aneurysms.

The experience with respect to the treatment of giant intracranial aneurysms with flow-diversion devices is limited. The aim of the present systematic review was to evaluate the effect of the pipeline embolization device (PED) on giant intracranial aneurysms. Eligible related articles were identified by searching the PubMed, Web of Science, Springer, ScienceDirect, and OVID databases using "giant aneurysm" and "pipeline" as the search items. The date of the last search was November 20, 2015. This systematic review adopted the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. In a total of 9 eligible studies with 200 patients and 215 aneurysms, 40 (18.6%) giant (aneurysm diameter >25mm) intracranial aneurysms treated with PED were analyzed. During a 6 to 34 month follow-up, complete occlusion was achieved in 23 (57.5%) cases. Seven patients (17.5%) developed intracranial hemorrhage, 5 developed ischemic attack (12.5%), and 13 (32.5%) developed a mass effect after PED treatment. The complication rate was 77.8% in PED for giant vertebrobasilar artery aneurysms. The cumulative mortality rate for giant paraclinoid carotid artery and middle cerebral artery aneurysms was 13.3% and increased up to 50% for giant vertebrobasilar artery aneurysms. The complete obliteration rate of PED for giant intracranial aneurysms was approximately 60%. Mass effect is the most mechanism of complications. Complication and mortality rates associated with PED for giant vertebrobasilar artery aneurysms are still extremely high.

Elderly female presenting with "lazy" giant intracranial aneurysm

Multiple aneurysms of anterior intracranial circulation including a giant one are rare; progressing slowly, these “little pulsatile bumps” often present with ocular and neurological symptoms. This case reports a 70-year-old hypertensive female with multiple small and a single giant intracranial aneurysm, diagnosed on basis of ophthalmological manifestations 3 years back, and the patient still survives with these unruptured vascular deformations.

A Pipeline Embolization Device for the Treatment of Large and Giant Intracranial Aneurysms: Initial Experience at a Single Center

A Pipeline Embolization Device for the Treatment of Large and Giant Intracranial Aneurysms: Initial Experience at a Single Center

Випадок комбінованого хірургічного лікування нерозірваної гігантської мішкоподібної аневризми супракліноїдного відділу правої внутрішньої сонної артерії

We tried to determine the optimal tactics of endovascular occlusion of a giant saccular aneurysm supraclinoid part of the right internal carotid artery, which moves right middle cerebral artery on the background of hypoplasia and stenosis of the right internal carotid artery (ICA) in petrous segment in conjunction with stenosis in the M1-segment of right middle cerebral artery (MCA) and deconstruction clinoid part of the right ICA using coils with maintaining adequate perfusion in right MCA. We analyzed the results of surgical treatment endovascular embolization of giant intracranial unruptured aneurysms, on the background of concomitant stenosis of the ICA (2 similar cases in my own practice). In all cases, regardless of the degree of ICA stenosis performed a stand-alone coiling of aneurysms occlusion. Stenting of the stenotic part of the ICA was not performed. The results of the combined 3-stage of surgical treatment (bypass, endovascular coiling-aneurysm occlusion of the ICA, deconstruction ICA) patient with a giant saccular aneurysm supraclinoid part of right ICA, from which departs right MCA, against the background of hypoplasia and stenosis of right ICA in the petrous segment in conjunction with stenosis in the M1-segment of right MCA. After 3 months the patient's condition by somatic satisfactory. Neurologically: remained moderate paresis of the abducens nerve on the right. The patient is recommended dynamic observation with conducting magnetic resonance imaging of the brain and cerebral angiography at 6 and 12 months. The analysis of the result of combined surgical treatment in the combined pathology of the cerebral vessels (saccular aneurysm, stenosis of right ICA, stenosis of right MCA). Showed that surgical tactics was justified and can be used as a method of treating this pathology.

The Utility of Ultrasound and Angio-Sonography in Management of Intracranial Giant Aneurysm

The Utility of Ultrasound and Angio-Sonography in Management of Intracranial Giant Aneurysm

When flow diverters fail: short review and a case illustration of a device failure

Abstract The ultimate aims of treatment of the intracranial aneurysms are reconstruction the vessel wall and correcting the hemodynamic disturbance. A flow diverter (FD) is a stent placed inside lumen of the parent artery with aim to blood flow reduction into the aneurysms sac to the extent of almost stagnation leading to gradual onset of progressive thrombosis and neointimal lining of arterial wall remodeling to maintain blood outflow into perforators the side and branches. Flow diverter is considered as an effective treatment for fusiform, wide-necked, large and giant intracranial unruptured aneurysms. However, FD implantation may also be associated with growth and rupture of residual aneurysms. The most frequent complication of endovascular aneurysms management is thromboembolic events and less common are intra and postoperative hemorrhagic aneurysmal rupture. Authors report a case where a lack of operation of the device as illustration is presented to demonstrate the shortcomings of this new type of devices.

Carotid-Cavernous Fistula Due to Giant Aneurysm in a Postpartum Woman

A carotid-cavernous fistula (CCF) is an abnormal communication between the venous cavernous sinus and the carotid artery. The rupture of an intracavernous aneurysm is usually caused by trauma, but spontaneous rupture can also occur, with pregnancy being a contributing factor. We report a case of direct CCF due to rupture of a giant aneurysm in a postpartum woman. Key Words: Carotid-cavernous fistula, Giant intracranial aneurysm, Postpartum

Pipeline embolization device for the treatment of intracranial aneurysms: a preliminary experience

Objective To investigate the clinical application value and technical characteristics of pipeline embolization device(PED)for the treatment of intracranial aneurysms. Methods From December 2014 to December 2015, the clinical data of 20 patients with intracranial aneurysm treated with PED at the Department of Neurosurgeries, Shanghai Punan Hospital of Pudong New District and Donglei Brain Surgeon Group were analyzed retrospectively. Fifteen patients had one aneurysm and 5 had multiple aneurysms. The diameters of 28 aneurysms were 2-33 mm(15.2±9.9 mm). The aneurysm necks of all patients were covered with 1 PED, and 8 of them were treated with the combined aneurysm coil embolization. Results The release of PEDs in all 20 patients was completed successfully. The coverage of aneurysm necks was satisfactory. PEDs were found well adhering to the wall. Immediately after surgery, it showed that contrast agents in aneurysm cavities were obviously detained. Three patients had complications of cerebral hemorrhage after procedure, including 1 died and 1 had hemiparesis at discharge. Eight patients were followed up by digital subtraction angiography(DSA)6 months later, 6 were cured completely, the aneurysm of 1 case was nearly completely occluded, and the size of a large aneurysm did not have obvious change. Two patients had asymptomatic anterior cerebral artery stenosis. The head MRI follow-up revealed that the mass effect of the large and giant intracranial aneurysms were significantly relieved or disappeared. The remaining 11 cases had to be followed up. Conclusions The efficacy of PED for the treatment of large and giant intracranial aneurysms, tandem multiple small aneurysms and intracranial blood blister-like aneurysms is satisfactory. This device has just begun to be applied in clinical practice in China. The complications and long-term efficacy of the large sample case analysis and research are needed. Key words: Intracranial aneurysm; Embolization, therapeutic; Pipeline embolization device

Wall enhancement on high-resolution magnetic resonance imaging may predict an unsteady state of an intracranial saccular aneurysm.

The aneurysm wall has been reported to play a critical role in the formation, development, and even rupture of an aneurysm. We used high-resolution magnetic resonance imaging (HRMRI) to investigate the aneurysm wall in an effort to identify evidence of inflammation invasion and define its relationship with aneurysm behavior. Patients with intracranial aneurysms who were prospectively evaluated using HRMRI between July 2013 and June 2014 were enrolled in this study. The aneurysm's wall enhancement and evidence of inflammation invasion were determined. In addition, the relationship between aneurysm wall enhancement and aneurysm size and symptoms, including ruptured aneurysms, giant unruputred intracranial aneurysms (UIAs) presenting as mass effect, progressively growing aneurysms, and aneurysms associated with neurological symptoms, was statistically analyzed. Twenty-five patients with 30 aneurysms were available for the current study. Fourteen aneurysms showed wall enhancement, including 6 ruptured and 8 unruptured aneurysms. Evidence of inflammation was identified directly through histological studies and indirectly through intraoperative investigations and clinical courses. The statistical analysis indicated no significant correlation between aneurysm wall enhancement and aneurysm size. However, there was a strong correlation between wall enhancement and aneurysm symptoms, with a kappa value of 0.86 (95% CI 0.68-1). Aneurysm wall enhancement on HRMRI might be a sign of inflammatory change. Symptomatic aneurysms exhibited wall enhancement on HRMRI. Wall enhancement had a high consistent correlation of symptomatic aneurysms. Therefore, wall enhancement on HRMRI might predict an unsteady state of an intracranial saccular aneurysm.

Long-Term Effect of Flow Diversion on Large and Giant Aneurysms: MRI-DSA Clinical Correlation Study

The long-term effect of flow diversion (FD) on aneurysms has not been well studied. We aimed to assess the effect of the Pipeline embolization device (Covidien, Irvine, California, USA) on large and giant intracranial aneurysms with magnetic resonance imaging (MRI) and digital subtraction angiography (DSA) and then correlate with clinical follow-up. We conducted a retrospective analysis of aneurysms treated solely with Pipeline without adjunctive therapy. The largest aneurysm diameters were compared with pretreatment and post treatment MRI and correlated with DSA and clinical symptoms. Twelve patients harboring large and giant saccular unruptured aneurysms, treated with Pipeline, were included. Mean follow-up times were as follows: MRI 22.8 months (range 1-57), DSA 18.2 months (range 1-33), and clinical 29 months (range 1-48). Ten (83%) of 12 treated aneurysms decreased in size on MRI, which was first seen at an average of 17 months (range 4-57). In 70% of patients the change was noted on MRI ≤1 year after treatment, at an average of 9.1 months (range 4-12). MRI reduction was more likely in angiographically occluded aneurysms. Five aneurysms with complete occlusion on early angiogram showed size reduction on MRI only at ≥12 months. Mean aneurysm size reduction was 57% (range 19.6-94.2), which correlated well with improvement of cranial neuropathies in 75% and headaches in 100% of patients. Most aneurysms treated with Pipeline decreased in size, correlating with clinical improvement. Some aneurysms remained unchanged on MRI until a later time point despite early DSA occlusion. It may be reasonable to eliminate early postprocedural imaging and start follow-up only as late as 1 year after FD treatment in clinically stable, asymptomatic patients.

PMD37 - COST-EFFECTIVENESS ANALYSIS OF PIPELINE® EMBOLIZATION DEVICE (PED) FOR THE TREATMENT OF UNRUPTURED INTRACRANIAL ANEURYSMS VERSUS STANDARD ENDOVASCULAR TREATMENT IN THE MEXICAN PUBLIC HEALTH CARE SYSTEM

The Pipeline Embolization Device (PED) is a flow diverter system designed to treat intracranial aneurysms. This study focuses on unruptured, wide neck, giant intracranial aneurysm, and aims at identifying the cost-effectiveness of PED compared with current standard therapies available in the Mexican public healthcare system. To predict clinical endpoints and costs over a 15-year time horizon, a decision analytic model (Markov) was developed. The model has a short-term component with three health states based on major radiologic outcomes: complete occlusion, residual neck, and residual aneurysm; and a long-term component with three health states: reintervention, rupture and death. The endovascular procedures of coiling and stent assisted coiling were identified as comparators. Clinical efficacy was measured using radiological outcomes; all clinical trials used the same assessment tools facilitating comparison. Costs were taken from public available sources considering direct medical costs only. Results were presented as incremental cost per life years gained in national currency. PED showed to have an ICER of $103,839.34 versus coiling, 117,043.87 when compared to stent-assisted coiling and $20,711.69 when compared with the no intervention strategy in a 15-year temporal horizon scenario. PED obtained an ICER below Mexican GDP threshold per life years gained, versus the rest of the competitors in the mentioned timeline. Other ICERs for different time horizons will be shown in the sensitivity analysis. PED represents a cost-effective strategy for the treatment of this particular type of aneurysmal lesions when compared with the current available endovascular treatment options in the Mexican public healthcare system.

Hemodynamic Effect of Flow Diverter and Coils in Treatment of Large and Giant Intracranial Aneurysms

This study aimed to investigate the hemodynamic changes induced by a flow diverter (FD) and coils in the treatment of internal carotid artery aneurysms, as well as to evaluate the effect of this treatment by using angiographic follow-up data. Six large and giant aneurysms were treated by the Tubridge FD and loose packing coils between June 2013 and May 2015. Patient-specific models were constructed and analyzed using a computational fluid dynamics (CFD) method. The virtual FD deployment method was used to implant the Tubridge stent into a 3-dimensional digital subtraction angiographic image of the aneurysms, and the coils were simulated by a porous medium model. Tubridge FD alone can significantly reduce the intra-aneurysmal flow velocity (0.17 ± 0.05 m/s-0.11 ± 0.06 m/s, P < 0.001) and wall shear stress (WSS, 1.39 ± 0.29 Pa-0.77 ± 0.34 Pa, P= 0.001) and increase the low wall shear area (LSA, 6.38% ± 1.49%-34.60% ± 28.90%, P= 0.047). Coils, as a supplementary measure, further reduced the velocity (0.11 ± 0.06 m/s-0.08 ± 0.05 m/s, P= 0.03) and WSS (0.77 ± 0.34 Pa-0.47 ± 0.35 Pa, P= 0.04) and increased the LSA (34.60% ± 28.90%-63.33% ± 34.82%, P= 0.044). Aneurysm with sustained strong inflow after treatment (case 3, 25% reduction in velocity, 12% reduction in WSS, and 16% increment in LSA) showed partial patency, whereas others with a weaker inflow jet (mean 56% reduction in velocity, 74% reduction in WSS, and 1081% increment in LSA) showed complete occlusion at follow-up. On the basis of using the CFD method, adjunctive coiling with the Tubridge FD placement may significantly reduce intra-aneurysmal flow velocity and WSS, promoting thrombosis formation and occlusion of aneurysms.

Abstract TP94: Effect of Flow Diversion on Large and Giant Aneurysms: an MRI-DSA Correlation Follow-up Study

Background: There is sparse literature on the effect of flow diversion (FD) on large or giant intracranial aneurysms. We assessed the effects of FD with Pipeline stent on aneurysm sac size using MRI follow-up Methods: All patients at our institution who underwent FD for treatment of intracranial aneurysms were retrospectively identified. Aneurysms with maximum dimension &gt; 20mm, with pre and post treatment MRI were selected. These aneurysms were not previously treated, and did not receive adjunctive devices for current treatment. The largest diameter in 2-dimensions was measured on the MRI sequence that best demonstrated the aneurysm sac, and compared on serial scans. MRI changes were compared to DSA where aneurysm occlusion was graded by the O'Kelly-Marotta (OKM) scale. Results: Between 6/2011-4/2015, 87 patients with 96 aneurysms were treated with FD. Eighteen patients had aneurysm &gt;20mm. Pre and post treatment MRI were available in 12/18 (67%) patients. This included 9 (75%) females, with mean age 65.5 years. All aneurysms were unruptured and symptomatic. Nine (75%) patients had cavernous/ophthalmic aneurysms, and 3 had basilar aneurysms. Average largest aneurysm diameter was 26.7 (range 21-37) mm. Pipeline was used in all patients (mean 1.9, range 1-5 stents), with 8 (67%) requiring &gt; 1 stent. At the first MRI follow-up (median 4, range 1-18 months), 4 (33%) aneurysms decreased in size, 6 (50%) remained stable, 1 (8%) increased in size. The stent thrombosed in the last patient. At the last MRI follow-up (median 10.5, range 1-48 months), 9 (75%) aneurysms decreased in size and 2 (16%) remained stable from baseline. No aneurysm completely resolved. DSA follow-up was available in 10 (83%) patients (median 9, range 1-25 months). Patients with decreased size on MRI had OKM grade C2, C3 or D, while aneurysms with stable size had OKM grade B3. The one patient with initial increased size on MR had corresponding OKM grade D (no filling). Conclusion: Majority (75%) of large aneurysms decrease in size on serial MRIs after FD treatment. This corresponds with no filling or early remnant on DSA. Rare aneurysms increase in size despite no filling on DSA, which suggests caution when using only DSA follow-up post treatment. These findings require further study.

Outcome of Surgical or Endovascular Treatment of Giant Intracranial Aneurysms, with Emphasis on Age, Aneurysm Location, and Unruptured Aneuryms - A Systematic Review and Meta-Analysis

Background: Designing treatment strategies for unruptured giant intracranial aneurysms (GIA) is difficult as evidence of large clinical trials is lacking. We examined the outcome following surgical or endovascular GIA treatment focusing on patient age, GIA location and unruptured GIA. Methods: Medline and Embase were searched for studies reporting on GIA treatment outcome published after January 2000. We calculated the proportion of good outcome (PGO) for all included GIA and for unruptured GIA by meta-analysis using a random effects model. Results: We included 54 studies containing 64 study populations with 1,269 GIA at a median follow-up time (FU-T) of 26.4 months (95% CI 10.8-42.0). PGO was 80.9% (77.4-84.4) in the analysis of all GIA compared to 81.2% (75.3-86.1) in the separate analysis of unruptured GIA. For each year added to patient age, PGO decreased by 0.8%, both for all GIA and unruptured GIA. For all GIA, surgical treatment resulted in a PGO of 80.3% (95% CI 76.0-84.6) compared to 84.2% (78.5-89.8, p = 0.27) after endovascular treatment. In unruptured GIA, PGO was 79.7% (95% CI 71.5-87.8) after surgical treatment and 84.9% (79.1-90.7, p = 0.54) after endovascular treatment. PGO was lower in high quality studies and in studies presenting aggregate instead of individual patient data. In unruptured GIA, the OR for good treatment outcome was 5.2 (95% CI 2.0-13.0) at the internal carotid artery compared to 0.1 (0.1-0.3, p < 0.1) in the posterior circulation. Patient sex, FU-T and prevalence of ruptured GIA were not associated with PGO. Conclusions: We found that the chances of good outcome after surgical or endovascular GIA treatment mainly depend on patient age and aneurysm location rather than on the type of treatment conducted. Our analysis may inform future research on GIA.

Results of deconstructive endovascular surgery in treatment of large and giant intracranial aneurysms

To clarify the indications for deconstructive endovascular surgery in patients with large and giant intracranial aneurysms and to evaluate short-term and long-term postoperative outcomes. The study was based on a retrospective analysis of the treatment results in 50 patients with large (15-25 mm) and giant (more than 25 mm) intracranial aneurysms, aged from 18 to 75 years, who were treated at the Burdenko Neurosurgical Institute in 2002-2014. The patients underwent a balloon occlusion test (BOT) in various modifications before stationary occlusion of the carrier artery. For vascular occlusion, we used detachable latex balloon catheters (33 cases) and microcoils (17 cases). The condition of patients in the pre- and postoperative period was assessed by using the modified Rankin Scale. There were no deaths due to occlusion of the internal carotid artery (37 patients). Postoperative complications occurred in 5 patients. On the basis of BOT, revascularization surgery involving placement of an extra-intracranial microanastomosis (EICMA) was performed in 6 cases. In more 4 cases, EICMA was placed in the early postoperative period due to developing signs of ischemia. Two of 7 patients underwent occlusion of both vertebral arteries (VAs) in the vertebrobasilar basin, which led to fatal outcomes. One more patient died of aggravation of brainstem compression after VA occlusion. There was no worsening of neurological symptoms among survivors. There were no deaths and persistent neurological disorders upon occlusion of branches of the main cerebral arteries, starting with the first order arteries (6patients). Thirty one patients (66%) were followed-up in the period from 1 to 104 months. There were no deaths associated with artery occlusion. Two patients experienced delayed ischemic disorders. Occlusion of the carrier artery should be performed in a carefully selected group of BOT-negative patients. This surgery can be indicated for aneurysms with a complicated configuration, the topographic and anatomical features of which exclude reconstructive surgery.

Treatment of ruptured complex and large/giant ruptured cerebral aneurysms by acute coiling followed by staged flow diversion.

OBJECT Flow-diversion treatment has been shown to be associated with high rates of angiographic obliteration; however, the treatment is relatively contraindicated in the acute phase following subarachnoid hemorrhage (SAH) as these patients require periprocedural dual antiplatelet therapy. Acute coiling followed by flow diversion has emerged as an intriguing and feasible treatment option for ruptured complex and giant aneurysms. In this study the authors report outcomes and complications of patients with ruptured aneurysms undergoing coiling in the acute phase followed by planned delayed flow diversion. METHODS This case series includes patients from 2 institutions. All patients underwent standard endovascular coiling in the acute phase after SAH with the intention and plan to proceed with flow diversion at a later date. Outcomes studied included angiographic occlusion, procedure-related complications, and long-term clinical outcome as measured using the modified Rankin Scale. RESULTS A total of 31 patients underwent coiling in the acute phase with the intention to undergo flow diversion at a later date. The mean aneurysm size was 15.8 ± 7.9 mm. Of the 31 patients undergoing coiling, 4 patients could not undergo further flow-diverter therapy: 3 patients (9.7%) died of complications of subarachnoid hemorrhage and 1 patient had permanent morbidity as a result of perioperative ischemic stroke (3.1%). Twenty-seven patients underwent staged placement of flow diverters after adequate recovery. The median time to treatment was 16 weeks. There was one case of aneurysm rebleeding following coil treatment. There were no cases of permanent morbidity or mortality resulting from flow-diverter treatment. Twenty-four patients underwent imaging follow-up; 18 of these patients had aneurysms that were completely or nearly completely occluded (58.1% on an intent-to-treat basis). At last follow-up (mean 18.3 months), 25 patients had mRS scores ≤ 2 (80.6% on an intent-to-treat basis). CONCLUSIONS Staged treatment of ruptured complex and giant intracranial aneurysms with coiling in the acute phase and flow-diverter treatment following recovery from SAH is both safe and effective. In this series, no cases of rebleeding occurred during the interval between coiling and flow diversion. This strategy should be considered as a valid option in patients presenting with these challenging ruptured aneurysms.

Giant Intracranial Aneurysms at 7T MRI.

Giant intracranial aneurysms are rare vascular pathologies associated with high morbidity and mortality. The purpose of this in vivo study was to assess giant intracranial aneurysms and their wall microstructure by 7T MR imaging, previously only visualized in histopathologic examinations. Seven giant intracranial aneurysms were evaluated, and 2 aneurysms were available for histopathologic examination. Six of 7 (85.7%) showed intraluminal thrombus of various sizes. Aneurysm walls were depicted as hypointense in TOF-MRA and SWI sequences with excellent contrast ratios to adjacent brain parenchyma (range, 0.01-0.60 and 0.58-0.96, respectively). The triple-layered microstructure of the aneurysm walls was visualized in all aneurysms in TOF-MRA and SWI. This could be related to iron deposition in the wall, similar to the findings in 2 available histopathologic specimens. In vivo 7T TOF-MRA and SWI can delineate the aneurysm wall and the triple-layered wall microstructure in giant intracranial aneurysms.

Treatment of Giant Intracranial Aneurysms: a Review Based on Experience from 286 Cases

Aneurysms are classified as giant when their largest diameter is equal to or greater than 25 mm, which represents approximately 5–7% of intracranial aneurysms. Severe disease with poor natural history presents with 68% mortality in two years and 85% in five years for untreated cases. Thus, in the majority of cases, the patients require treatment, despite the risks of therapeutic options. We discuss the epidemiology, natural history, diagnosis, and treatment of giant aneurysms based on the experience of 286 operations and literature data.

An automatic CFD-based flow diverter optimization principle for patient-specific intracranial aneurysms

The optimal treatment of intracranial aneurysms using flow diverting devices is a fundamental issue for neuroradiologists as well as neurosurgeons. Due to highly irregular manifold aneurysm shapes and locations, the choice of the stent and the patient-specific deployment strategy can be a very difficult decision.To support the therapy planning, a new method is introduced that combines a three-dimensional CFD-based optimization with a realistic deployment of a virtual flow diverting stent for a given aneurysm. To demonstrate the feasibility of this method, it was applied to a patient-specific intracranial giant aneurysm that was successfully treated using a commercial flow diverter. Eight treatment scenarios with different local compressions were considered in a fully automated simulation loop. The impact on the corresponding blood flow behavior was evaluated qualitatively as well as quantitatively, and the optimal configuration for this specific case was identified.The virtual deployment of an uncompressed flow diverter reduced the inflow into the aneurysm by 24.4% compared to the untreated case. Depending on the positioning of the local stent compression below the ostium, blood flow reduction could vary between 27.3% and 33.4%. Therefore, a broad range of potential treatment outcomes was identified, illustrating the variability of a given flow diverter deployment in general.This method represents a proof of concept to automatically identify the optimal treatment for a patient in a virtual study under certain assumptions. Hence, it contributes to the improvement of virtual stenting for intracranial aneurysms and can support physicians during therapy planning in the future.

Interobserver variability in the characterization of giant intracranial aneurysms with special emphasis on aneurysm diameter and shape

The Giant Intracranial Aneurysm Registry is a multicenter observational trial exclusively focusing on giant intracranial aneurysms (GIA). As no data exist on the interobserver variability in the radiological description of GIA, there is some uncertainty concerning the reliability of the GIA characteristics included in the registry. We have therefore designed a study to test the interobserver variability in the description of the specific GIA characteristics that are examined in the GIA registry. Six different raters analyzed imaging of five GIA concerning GIA location, GIA size, GIA shape, GIA thrombosis, and the presence of perianeurysmal edema. Interobserver variability was examined using intraclass correlation and Fleiss' kappa analysis. The intraclass correlation coefficient was 0.99 (95 % CI 0.97-1.0) for the largest GIA diameter and 0.98 (95 % CI 0.94-1.0) for the largest GIA diameter in an axial imaging slice. We found perfect interobserver agreement (Fleiss' kappa 1.00) in the characterization of GIA location and the presence of perianeurysmal edema and almost perfect interobserver agreement for GIA thrombosis (Fleiss' kappa 0.86, 95 % CI 0.63-1.00). Only moderate interobserver agreement was found in the description of GIA shape (Fleiss' kappa 0.50, 95 % CI 0.27-0.73). While GIA size, location, thrombosis, and the presence of perianeurysmal edema showed excellent interobserver agreement, the description of GIA shape was achieved with only moderate agreement. Data on GIA shape in multicenter studies, like the GIA registry, should therefore be discussed with caution and potentially reassessed in a centralized fashion.