Knowledge domain and emerging trends in the rupture risk of intracranial aneurysms research from 2004 to 2023

BACKGROUND Intracranial aneurysms(IAs)pose significant health risks,attributable to their potential for sudden rupture,which can result in severe outcomes such as stroke and death.Despite extensive research,the variability of aneurysm behavior,with some remaining stable for years while others rupture unexpectedly,remains poorly understood.AIM To employ bibliometric analysis to map the research landscape concerning risk factors associated with IAs rupture.METHODS A systematic literature review of publications from 2004 to 2023 was conducted,analyzing 3804 documents from the Web of Science Core Collection database,with a focus on full-text articles and reviews in English.The analysis encompassed citation and co-citation networks,keyword bursts,and temporal trends to delineate the evolution of research themes and collaboration patterns.Advanced software tools,CiteSpace and VOSviewer,were utilized for comprehensive data visualization and trend analysis.RESULTS Analysis uncovered a total of 3804 publications on IA rupture risk factors between 2006 and 2023.Research interest surged after 2013,peaking in 2023.The United States led with 28.97%of publications,garnering 37706 citations.Notable United States-China collaborations were observed.Capital Medical University produced 184 publications,while Utrecht University boasted a citation average of 69.62 per publication.“World Neurosurgery”published the most papers,contrasting with“Stroke”,the most cited journal.The PHASES score from“Lancet Neurology”emerged as a vital rupture risk prediction tool.Early research favored endovascular therapy,transitioning to magnetic resonance imaging and flow diverters.CONCLUSION This study assesses global IA research trends and highlights crucial gaps,guiding future investigations to improve preventive and therapeutic approaches.

Safety and Effectiveness of Stent-Assisted Coil Embolization for Ruptured Intracranial Aneurysm

Background: It has been conclusively established that intracranial aneurysms measuring a diameter below 7 mm pose a minimal risk of rupture. Conversely, those exhibiting irregular morphology or featuring the presence of a sac necessitate a more stringent and rigorous management approach. Objective: The primary aim of this study is to delve into the morphological features of ruptured aneurysms situated in distinct regions of the brain. Furthermore, we endeavor to assess the degree of safety and efficacy associated with stent-assisted embolization as a treatment modality for these ruptured aneurysms. Methods: This retrospective study encompassed a cohort of 467 patients who presented with intracranial ruptured aneurysms and were diagnosed through a combination of computed tomography (CT) and digital subtraction angiography (DSA) at Nanfang Hospital of Southern Medical University, spanning from January 2009 to December 2019. The following clinical parameters were meticulously recorded: aneurysm height, width, neck measurements, immediate Raymond grade assessments, and any perioperative complications experienced. Results: Within the study population, the average dimensions of ruptured aneurysms were found to be 4.26 ± 2.10 mm (width), 4.86 ± 2.38 mm (height), and 4.04 ± 1.87 mm (neck). Categorically, the most prevalent types of aneurysms were 170 cases of anterior communicating artery aneurysms (accounting for 36.4%), followed by 161 cases of posterior communicating artery aneurysms (34.5%), 56 cases of middle cerebral artery aneurysms (12.0%), 13 cases of anterior cerebral artery aneurysms (2.8%), 45 cases of paraclinoid aneurysms (9.6%), 6 cases of superior pituitary artery aneurysms (1.3%), 7 cases of anterior choroidal artery aneurysms (1.5%), and 9 cases of vertebrobasilar artery aneurysms (2.0%). Notably, 18 patients (3.9%) presented with ruptured aneurysms coexisting with ascus. Regarding treatment approaches, 228 cases (48.8%) underwent stent-assisted embolization, 234 cases (50.1%) received coils embolization, and 5 cases (1.1%) were treated with the dual-catheter technique. Immediately post-treatment, 422 patients (90.4%) attained a Raymond Class I status, with a procedure-related complication rate of 0.9%. Importantly, no statistically significant differences were observed in the incidence of perioperative complications across the three distinct treatment groups (P = 0.505). Conclusion: The outcomes of this study affirm the safety and efficacy of stent-assisted embolization as a treatment modality for ruptured aneurysms.

COMPLICATION ANALYSIS OF INTRACRANIAL ANEURYSM EMBOLIZATION WITH CONTROLLABLE COILS

Objective To explore the causes, prevention, and management of the complications during intra-cranial aneurysm embolization with controllable coils (mechanical detachable spiral, MDS; and Guglielmi detachable coil, GDC). Methods Retrospective review of 120 cases with 125 intracranial aneurysms embolized with con-trollable coils from March 1995 to July 1999 was conducted. The 20 accidents(in 18 cases) including aneurysm rupture, over-embolization, protrusion of coil end into the parent artery, and thrombosis of the parent artery were analyzed. Results Among the 20 accidents, there were 6 aneurysm ruptures, 6 over-embolizations (in 5 cases), 6 coil protrusions, and 2 thromboses (one was secondary to coil protrusion). The embolization-related mortality was 3.33% (4/120), the permanent neurological deficit was 1.67% (2/120), and the transitory neurological deficit was 3.33%(4/120). The occurrence and outcome of the complications were related to the embolizing technique, the pattern of aneurysm and its parent artery, the imperfection of embolic materials, and the observation and management during embolization. Conclusion Skilled embolizing technique, better understanding of the angio-anatomy of an aneurysm and its parent artery, correct judgement and management during embolization, and improvement of embolic materials are beneficial to the reduction of complications and to the melioration of the outcome of complications.

Neuroprotective effect of bispectral index-guided fast-track anesthesia using sevoflurane combined with dexmedetomidine for intracranial aneurysm embolization

Dexmedetomidine has sedative, anxiolytic, analgesic, anti-sympathetic, and anti-shivering effects. Dexmedetomidine might be effective in combination with sevoflurane for anesthesia, but prospective randomized controlled clinical trials with which to verify this hypothesis are lacking. In total, 120 patients who underwent embolization of an intracranial aneurysm were recruited from Anhui Provincial Hospital and Renmin Hospital of Wuhan University of China and randomly allocated to two groups. After intraoperative administration of 2% to 3% sevoflurane inhalation, one group of patients received pump-controlled intravenous injection of 1.0 ~tg/kg dexmedetomidine for 15 minutes followed by maintenance with 0.3 ~tg/kg/h until the end of surgery; the other group of patients only underwent pump-controlled infusion of saline. Bispectral index monitoring revealed that dexmedetomidine-assisted anesthesia can shorten the recovery time of spon- taneous breathing, time to eye opening, and time to laryngeal mask removal. Before anesthetic induction and immediately after laryngeal mask airway removal, the glucose and lactate levels were low, the S100~ and neuron-specific enolase levels were low, the perioperative blood pressure and heart rate were stable, and postoperative delirium was minimal. These findings indicate that dexmedetomidine can effectively assist sevoflurane for anesthesia during surgical embolization of intracranial aneurysms, shorten the time to consciousness and extubation, reduce the stress response and energy metabolism, stabilize hemodynamic parameters, and reduce adverse reactions, thereby reducing the damage to the central nervous system. This trial was registered at the Chinese Clinical Trial Registry （http：//www.chictr.org. cn/） （registration number： ChiCTR-IPR- 16008113）.

Correlation between MMP-2 and NF-κ B expression of intracranial aneurysm

Objective:To investigate the correlation between expressions of MMP-2 and NF-κB in the intracranial aneurysm wall,and explore their role in the mechanism of the occurrence,growth and rupture of intracranial aneurysms.Methods:RT-PCR was used to detect the expression of MMP-2 and NF-κB mRNA of 30 cases of intracranial aneurysm tissue and 10 cases of normal intracranial arterial tissue:Immunohistochemical method was used to detect the expression of MMP-2 and NF-κB protein.Results:the semi-quantitative analysis of MMP-2 and NF-κB in aneurysms tissues and normal tissues were statistically significant different from each other(P【0 05).Immunohistochemical staining results showed NF-κB was expressed in different layers.The expression of them were positive in intimal and medial,and the expression sites were located in the nucleus.MMP-2 were expressed in different layers of the aneurysm wall,and the expressions were positive in media and extima.The MMP-2 and NF-κB-positive expression of aneurysm wall were significantly higher than in normal cerebral arteries(P【0.05).MMP-2 and NF-κB mRNA expression showed positive correlation in the aneurysm wall tissue(r = 0.689,P = 0.005). Conclusions:The expressions of MMP-2 and NF-κB in the intracranial aneurysm wall tissue were significantly higher than in the normal intracranial arterial tissues.They have a synergistic effect on the formation of intracranial aneurysms.

Wall shear stress in intracranial aneurysms and adjacent arteries

Hemodynamic parameters play an important role in aneurysm formation and growth. However, it is difficult to directly observe a rapidly growing de novo aneurysm in a patient. To investigate possible associations between hemodynamic parameters and the formation and growth of intracranial aneurysms, the present study constructed a computational model of a case with an internal carotid artery aneurysm and an anterior communicating artery aneurysm, based on the CT angiography findings of a patient. To simulate the formation of the anterior communicating artery aneurysm and the growth of the internal carotid artery aneurysm, we then constructed a model that virtually removed the anterior communicating artery aneurysm, and a further two models that also progressively decreased the size of the internal carotid artery aneurysm. Computational simulations of the fluid dynamics of the four models were performed under pulsatile flow conditions, and wall shear stress was compared among the different models. In the three aneurysm growth models, increasing size of the aneurysm was associated with an increased area of low wall shear stress, a significant decrease in wall shear stress at the dome of the aneurysm, and a significant change in the wall shear stress of the parent artery. The wall shear stress of the anterior communicating artery remained low, and was significantly lower than the wall shear stress at the bifurcation of the internal carotid artery or the bifurcation of the middle cerebral artery. After formation of the anterior communicating artery aneurysm, the wall shear stress at the dome of the internal carotid artery aneurysm increased significantly, and the wall shear stress in the upstream arteries also changed significantly. These findings indicate that low wall shear stress may be associated with the initiation and growth of aneurysms, and that aneurysm formation and growth may influence hemodynamic parameters in the local and adjacent arteries.

Nursing care of 22 patients with complex intracranial aneurysms treated with flow-diverting stents:A retrospective study

Objective:To summarize the nursing treatment of patients who underwent implantation of a blood flow diverter to treat complex intracranial aneurysms.Methods:Data from 22 patients with complex aneurysms,diagnosed at an interventional center for blood flow diverter implantation between February 2015 and February 2016,treated in the Henan Provincial People’s Hospital(Zhengzhou,China),were retrospectively analyzed.Nursing methods,including preoperative,intraoperative,and postoperative care,were analyzed.Results:All 22 patients underwent successful surgery,with no related complications or hospital mortality,and were cured in hospital.Conclusion:Interventional flow diverter therapy for patients with complex intracranial aneurysms is a new technology,and involves intensive care by nursing staff and appears to be a promising new treatment method.

Effectiveness of MRA on embolized intracranial aneurysms: a comparison of DSA, CE-MRA, and TOF-MRA

Purpose: The endovascular treatment of intracranial aneurysms was proven safe and effective compared to the alternative method of surgical clipping, despite the high recurrence rate. Follow-up of embolized intracranial aneurysms is mandatory for the early detection of recurrence and improved outcomes. DSA is used as the reference standard for this assessment. To determine the effectiveness of MRA in follow-up evaluations of intracranial aneurysms after embolization by comparing DSA, CE-MRA, and TOF-MRA. Materials and Methods: Sixty-eight consecutive patients undergoing DSA, TOF-MRA, and CE-MRA during an interval of <1 week were enrolled in this 6-month study. Images were evaluated for occlusion status, patency of the parent vessels, and artifacts. The modified Raymond-Roy occlusion classification and Aneurysm Embolization Grades were used to assess the occlusion status and initial DSA images for detection of recurrence in two filtered study phases with optimized selection criteria. Seventeen observers(phase I: 9, phase II: 8) independently interpreted the double-blinded images. Agreement was expressed with a Fleiss kappa value; p < 0.05 was considered significant. Results: This study included 68 patients with 77 aneurysms; 38(49.35%) were treated with coil alone and 39(50.65%) with stent-assisted coiling. In both phases, DSA was superior to TOF-MRA and CE-MRA using MRRC(Phase I: k = 0.567, p ≤ 0.001; k = 0.287, p ≤ 0.001; k = 0.117, p ≤ 0.001, respectively; Phase II: k = 0.503, p ≤ 0.001; k = 0.303, p ≤ 0.001; k = 0.115, p = 0.038, respectively). TOF-MRA was as effective as DSA(TOF: k = 0.335, p ≤ 0.001; DSA: k = 0.323, p ≤ 0.001) for recurrence detection. Conclusion: We suggest TOF-MRA as a first-line follow-up tool to detect aneurysm recurrence, and DSA to quantify the filling space to make a definite decision on re-embolization.

Evaluation of the safety and efficacy of a Pipeline Flex embolization device for treatment of large, wide-necked intracranial aneurysms

Objective: To investigate the safety and effectiveness of the Pipeline Flex embolization device(PFED) in the treatment of large and wide-necked aneurysms in the internal carotid artery(ICA). Methods: The clinical data of 78 cases of large and wide-necked aneurysms in the ICA treated with this Pipeline Flex embolization device in Shanghai Hospital of the Second Military Medical University and Southern Hospital of Southern Medical University from February 2017 to June 2018 were retrospectively analyzed. Results: A total of 66 cases were treated with a Pipeline Flex embolization device, 10 with a pipeline flex embolization device, and 2 with a double tubride stent(10 patients were treated with a pipeline stent-assisted coil embolization in; and 2 patients were treated with two pipeline stents). The patients were followed up for 3 to 18 months(average, 9.25 months). Among them, 63 cases had complete occlusion of the neck of the aneurysm(Raymondl Class I; MRS score 0; 80.8%). Aneurysms recurred in 12 cases(Raymondl Class Ⅱ; MRS score 1; 15.4%). Delayed ischemic complications were observed in 1 case(MRS score >2; 0.13%). There was 1 case of poor release of stent and 1 case of stent stenosis(0.13%). Conclusion: The treatment of large, wide-necked aneurysms in the ICA with PFED has a high total occlusion rate and good prognosis was better than coil embolization, but the placement of PFED still has some neurological complications.

Applications of multislice CT angiography in the surgical clipping and endovascular coiling of intracranial aneurysms

Prompt diagnosis and therapy of aneurysms are critical for patients with nontraumatic subarachnoid hemorrhage （SAH）.The aim of our study was to assess the clinical usefulness of multislice computed tomography angiography （CTA） in the surgical and endovascular treatment of intracranial aneurysms.A total of 195 cases with 206 intracranial aneurysms underwent CTA.Fifty （24%） aneurysms underwent surgical clipping while 156 （76%） aneurysms underwent endovascular coiling.In the five missed aneurysms at digital substraction angiography and the nine aneurysms with mass intracerebral hematomas,surgical treatment was successfully performed based on 16-slice CTA alone,and the other 36 aneurysms were clipped on the main basis of the CTA.The intraoperative findings correlated well with the CTA findings and all aneurysms were clipped successfully.Sixteen-slice CTA image information has been shown to determine the choice of aneurysm therapy and assist the surgical and endovascular treatment of intracranial aneurysms.

Efficacy of pipeline endovascular device and Willis stent graft in the treatment of traumatic pseudo intracranial aneurysms

Objective:To investigate the advantages and effects of pipeline embolization device(PED)or Willis stent,in treating traumatic pseudoaneurysms.Traumatic pseudo intracranial aneurysms(TPIA)can be caused by either direct trauma or iatrogenic injuries,usually caused by direct arterial wall injury or shear due to acceleration.We describe a series of patients with TPIA who received a PED or Willis stent.Materials and methods:Retrospective analysis was performed on nine patients with TPIA admitted to the southern hospital of Southern Medical University from December 2017 to June 2019,of whom four were treated with PED and five were implanted with six Willis covered stents.The occlusive rate and complication in the two kinds of stents were compared by postoperative follow-up and modified rankin score(MRS).Results:After the implantation of PED,four patients showed an immediate stagnation of blood flow or a decreased filling in aneurysms,three out of four patients exhibited complete occlusion,and the remaining patient had nearly complete occlusion.Four out of five cases of Willis stent implantation were associated with immediate complete occlusion of aneurysms,and the modified rankin score of these patients ranged from 0 to 1.One patient died of unassociated complications.Conclusion:For different types of TPIA in the internal carotid artery(ICA),PED and Willis stents provide significant advantages in treatment,with fewer postoperative complications and prognosis well.

Preoperative diagnosis and operative effect of intracranial aneurysm with three-dimensional computed tomography angiography

BACKGROUND ： Digital subtraction angiography （DSA） is always regarded as the golden standard for diagnosis of intracranial aneurysm; however, the procedure is complex, traumatic, expensive and easy to induce vascular complication. Three-dimensional computed tomography angiography （3D-CTA） can make up deficiencies of DSA; therefore, it is used in clinical therapy wider and wider. OBJECTIVE ： To evaluate the clinical effect of 3D-CTA on disruption and hemorrhage of intracranial aneurysm pre- and post-operation and compare with the effect of DSA. DESIGN ： Auto-control contrast observation SETTING ： Department of Neurosurgery, Shengjing Hospital of China Medical University PARTICIPANTS ： A number of 106 patients with disruption and hemorrhage of intracranial aneurysm were selected from the Department of Neurosurgery, Shengjing Hospital of China Medical University from January 2003 to April 2006. All patients were diagnosed with cranial operation and consent. There were 47 males and 59 females aged from 3-76 years with the mean age of （47±13） years. Among them, 82 patients had extensive subarachnoid hemorrhage （SAH）, 7 had hemorrhage at longitudinal fissure, and 17 had hemorrhage at ambiens cistema and lateral fissure. Moreover, intraventricular hematocele was accompanied on 13 patients and hematom on 9 patients. METHODS： （1） 3D-CTA examination： Siemens SOMATOM Sensation 64 CT was used in this study. The thickness was 1 mm and interval of reconstruction was 0.8 mm. Localizing section was plainly scanned as the standard of canthus line. Scan ranged from 30 mm below sella to 50 mm above sella. Non-ion contrast medium of Omnipaque 350 （concentration of iodine was 350 g/L） was inserted into anterior vein of elbow with 18G trochar retained with high-pressured injectoc pum. The speed was 4.5 mL/s and the total volume was 80-100 mL with the means of 90 mL. Scan started at 10-20 s after injection of contrast medium. Original image was dealt with Leonardo workstation and retreated with Syngo software. Volume rendering and maximum intensity projection were used to reconstructed images, （2） All 106 patients suffered from occlusion of aneurysm clamp. Before operation, 3D-CTA was undertaken and DSA was followed. After operation, patients were rechecked with 3D-CTA. MAIN OUTCOME MEASURES： Comparisons between 3D-CTA and DSA. RESULTS ： All 106 patients were involved in the final analysis. （1） Examination of 3D-CTA and DSA： Among 118 patients with aneurysm, 110 were checked with 3D-CTA and the detected rate was 93.2% （110/118）. Among other 8 cases, 3 were negative and checked again with DSA; 1 had pericallosal aneurysm, 1 ophthalmic aneurysm, and 1 anterior choroidal artery of aneurysm. 3D-CTA results of other 5 cases were suspicious, and then, they were regarded as having aneurysm with DSA. Before operation, correlation among site, body, neck of aneurysm and peripheral anatomic structure were shown sufficiently. After operation, 82 patients were rechecked with 3D-CTA, which was complete occlusion, precise, unobvious constriction, emphraxis or remains as compared with 3D-CTA those pre-operation. （2） Characteristics of 3D-CTA： With multiple vessels and angles, 3D-CTA observed the relationship between aneurysm neck and carried artery and showed thrombosis in cavity of aneurysm, calcification of aneurysm wall and peripheral structure of vessel at the same time. However, DSA could not detect the reactions mentioned above. It could delete image of cranium, simulate image of operative route, eliminate artifact induced by metal, but not distinguish blood stream direction. Meanwhile, posterior communicating artery was always poor during circle of Willis artery showing. CONCLUSION： （1） 3D-CTA is characterized by simple operation and non-invasive showing vascular stereo structure and correlation. Therefore, it is significant for diagnosis and designing plan of operative approach and focal location pre-operation and evaluating effect post-operation. （2） 3D-CTA does not completely replace DSA on the diagnosis of intracranial aneurysm.

Influence of the aspect ratio on the endovascular treatment of intracranial aneurysms: A computational investigation

Intracranial aneurysm, a localized dilation of arterial blood vessels in the Circle of Willis and its branches, is potentially life threatening, due to massive bleeding in the subarachnoid space upon rupture. In clinical practice, one minimally invasive surgical procedure is the implantation of a metallic stent to cover the aneurysm neck. This flow diverting device can reduce the flow into the aneurysm and enhance the prospect of thrombosis, a condition expected to reduce the risk of growth and rupture. The biomechanical and haemo-dynamic factors in stented and nonstented situations are studied by computational fluid dynamics. Unlike earlier models with straight or curved parent blood vessels, the aneurysm is now located near an arterial bifurcation. The influence of the aspect (depth to neck) ratio of the aneurysm on the flow dynamics will be emphasized, especially in the post-operation stages. More precisely, the maximum flow velocity, the variations of wall shear stress, the risk of stent migration and volumetric flow rate after endovascular treatment will be studied. Aneurysms with larger aspect ratios (i.e. smaller neck sizes for constant depth) generally pose a greater risk in terms of these flow parameters. These results will assist the applications and design of stents in future neurosurgical therapy. The approach is limited to a nonelastic model, without taking into account of questions like stent expansion and interaction with tissue.

Morphological characteristics associated with rupture risk of multiple intracranial aneurysms

Objective: To identify the morphological parameters that are related to intracranial aneurysms(IAs) rupture using a case-control model.Methods: A total of 107 patients with multiple IAs and aneurysmal subarachnoid hemorrhage between August 2011 and February 2017 were enrolled in this study.Characteristics of IAs location, shape, neck width, perpendicular height, depth, maximum size, flow angle, parent vessel diameter(PVD), aspect ratio(AR) and size ratio(SR) were evaluated using CT angiography.Multiple logistic regression analysis was used to identify the independent risk factors associated with IAs rupture.Receiver operating characteristic curve analysis was performed on the final model, and the optimal thresholds were obtained.Results: IAs located in the internal carotid artery(ICA) was associated with a negative risk of rupture, whereas AR, SR1(height/PVD) and SR2(depth/PVD) were associated with increased risk of rupture.When SR was calculated differently, the odds ratio values of these factors were also different.The receiver operating characteristic curve showed that AR, SR1 and SR2 had cut-off values of 1.01, 1.48 and 1.40, respectively.SR3(maximum size/PVD) was not associated with IAs rupture.Conclusions: IAs located in the ICA are associated with a negative risk of rupture, while high AR(>1.01), SR1(>1.48) or SR2(>1.40) are risk factors for multiple IAs rupture.

Safety and efficacy of complete versus near-complete coiling in treatment of intracranial aneurysms

Objective:This study aimed to evaluate the clinical and angiographic outcomes of aneurysms that were completely or near-completely embolized and ascertain whether complete embolization is important in the stent-assisted coiling(SAC)of intracranial aneurysms.Methods:This retrospective study enrolled 390 patients(417 aneurysms).Among them,complete(100%)or nearcomplete(>90%)angiographic obliteration of the aneurysms on immediate angiography was accomplished.Baseline characteristics,complications,angiography follow-up results,and clinical outcomes were analyzed.Results:Cumulative adverse events occurred in 30 patients(7.7%),including thromboembolic complications in 17(4.4%),intraoperative rupture in 10(2.6%),and others in 3(0.8%).Statistical analyses revealed an increased intraprocedural rupture rate in the initial completely occluded aneurysms(5.6%compared with 1.0%).The incidence of cumulative adverse events was higher in patients with completely occluded aneurysms(11.1%)than in those with near-completely occluded aneurysms(5.5%).Angiography follow-up was available for 173 aneurysms.Aneurysm occlusion status at follow-up was correlated with stent placement(p?0.000,odds ratio?5.847),size(p?0.000,odds ratio?6.446 for tiny aneurysms;and p?0.001,odds ratio?5.616 for small aneurysms),and initial aneurysm occlusion status(p?0.001,odds ratio?3.436).Complete occlusion at followup was seen in 82.6%of the initial complete occlusion group versus 63.0%of the initial near-complete occlusion group.The incidence of complete occlusion at follow-up was higher in the initial completely occluded aneurysms with SAC(100%)than in the initial completely occluded aneurysms with non-SAC(65.2%).Conclusions:Initial complete treatment may lead to higher complication rates and good clinical outcomes at follow-up.Stent placement may enhance progressive aneurysm occlusion.Initial complete occlusion with SAC can provide durable closure at follow-up.

The effects of stent porosity on the endovascular treatment of intracranial aneurysms located near a bifurcation

Intracranial aneurysm occurs when a cerebral artery develops an abnormal sac-like dilatation, and will cause massive bleeding in the subarachnoid space upon rupture. Endovascular stenting is a minimally invasive procedure in which a flow-diverting stent is deployed to cover the aneurysm neck, thereby restricting blood from entering the aneurysm and reducing the risk of rupture. The stent porosity, a crucial factor determining the intra-aneurysmal hemodynamics following treatment, is investigated by computational fluid dynamics techniques. Based on the computational results, a low porosity stent will dramatically reduce the flow velocity and the flow rate inside the side branch vessel. Conversely, a high porosity stent may not provide adequate flow reduction inside the aneurysm, possibly causing treatment failure. An advisable range of optimal stent porosity would be 60% to 75%, which can drastically reduce the flow rate into the aneurysm while preserving enough blood flow for the side branch vessel. Clinically, deployment of two or more flow-diverting stents may not increase treatment efficacy but can potentially lead to adverse effects due to side-branch hypoperfusion. The present quantitative analysis can also provide practical insight for future stent design.

Is type Ⅰ alpha 2 collagen gene responsible for intracranial aneurysm in Northeast China?

In this study, we investigated whether a single nucleotide polymorphism （rs42524 G 〉 C） in the type I alpha 2 collagen gene was associated with sporadic ruptured intracranial aneurysm or its clinical characteristics in patients from Northeast China. Genotyping of the rs42524 G 〉 C polymorphism was carried out using a polymerase chain reaction-restriction fragment length polymorphism assay. The data showed that the frequency of the rs42524 GC ＋ CC genotype was significantly higher than the GG genotype among intracranial aneurysm patients whose Hunt and Hess grading scale was 〉 3. In addition, the rs42524 G 〉 C genotype was found to have a statistically significant association with intracranial aneurysm risk. These findings indicate that the type I alpha 2 collagen gene gene may be involved in a predisposition to intracranial aneurysm in the Northeast Chinese population. Crucially, the rs42524 C allele may be an important risk factor for increased severity of the condition in patients with ruptured intracranial aneurysms.

Intracranial aneurysm with neck indistinguishable from surrounding artery branches by cerebral angiography

The aim of this study is to examine morphology of intracranial aneurysm with neck indistinguishable from surrounding artery branches by cerebral angiography and discuss whether such aneurysms can be treated by interventional embolization. 6 patients who had not been treated by embolization due to irregular wide-necked aneurysms indistinguishable from surrounding artery branches by cerebral angiography received craniotomy for aneurysm clipping. The operations succeeded. Morphologically, neck width and location of the aneurysms were carefully observed and photographed from different directions and multi-angles during operation. The intraoperative findings were compared with the preoperative CTA and DSA images. Walls of the 6 patients’ aneurysms tightly clung to or adhered to surrounding branches and oppressed the branches into arcs, similar to the aneurysm walls in shape, and arterial branches and aneurysm walls suffered from segmental adhesion. In addition, abnormalities of communicating arteries to vary degrees were observed in 4 patients. However, after successful surgical clipping, it was revealed that the aneurysms would have been better treated by embolization since they are basically saccular aneurysms with regular sizes. Deformations in preoperative angiography may be due to anatomical variations of surrounding vessels near the aneurysms, aneurysm wall oppression or incomplete adhesion of surrounding arterial branches. Such deformations can be recognized by careful observation in preoperative angiography from different directions and multi-angles.

Ruptured intracranial aneurysm presenting as cerebral circulation insufficiency:A case report

BACKGROUND Rupture of an intracranial aneurysm is a type of acute stroke that is a serious threat to human health.Misdiagnosis of ruptured intracranial aneurysms is a serious clinical event that may have disastrous consequences in some patients.To date,ruptured intracranial aneurysms have been misdiagnosed as meningitis,tumors,stroke,or trauma,among other conditions.Here,we report what appears to be the first case of a ruptured intracranial aneurysm that presented as cerebral circulation insufficiency.CASE SUMMARY A middle-aged man was admitted to our hospital because of a parasellar lesion identified on a noncontrast computed tomography(CT)image after a mild traffic accident that was caused by a brief loss of consciousness.Notably,he was diagnosed with cerebral circulation insufficiency after two unexplained episodes of a transient loss of consciousness within the past 8 mo.The patient was diagnosed with right internal carotid artery aneurysm based on CT angiography and completely recovered after a craniotomy at our hospital.A few clots and severe adhesions around the aneurysm were observed in the subarachnoid space during the operation,suggesting that the aneurysm had ruptured and may had been misdiagnosed as cerebral circulation insufficiency.CONCLUSION Ruptured intracranial aneurysms may show negative imaging results and present as cerebral circulation insufficiency,which should be recognized as soon as possible to ensure timely management.

Application of 3D T1-SPACE combined with 3D-TOF sequence for follow-up evaluation of stent-assisted coil embolization for intracranial aneurysm

Objectives:To assess 3D T1-SPACE combined with 3D-TOF sequence for follow-up evaluation of stent-assisted coil embolization for intracranial aneurysm.Materials and methods:Between Oct 2018 and May 2019,we enrolled 25 patients with intracranial aneurysm who underwent stent-assisted coil embolization.All patients were followed up for 6 to10 months after endovascular treatment(EVT)using 3D-TOF MRA,3D T1-SPACE and DSA to evaluate aneurysm occlusion and parent artery patency.Results:With regards to aneurysm occlusion,the specificity of 3D-TOF MRA was 86.9%(20/23)and the accuracy was 84%(21/25).There was no statistical significance(P=0.409)compared with the DSA.The parent artery by3D-TOF MRA showed that there were 14 patients with grade 3,8 patients with grade 2 and 3 patients with grade1.However,3D T1-SPACE showed that all 25 patients were grade 4,and were clearly displayed without metal artifacts.The comparison of the two MR techniques demonstrated that 3D T1-SPACE was superior to 3D-TOF MRA in the evaluation of parent artery(P<0.001).Conclusions:3D T1-SPACE sequence provides better image quality and higher accuracy for evaluating stented parent arteries compared to TOF-MRA.This study also shows that 3D-TOF MRA has a merit to evaluate aneurysm occlusion.The combination of these two modalities can be used as an optional follow-up evaluation after EVT of intracranial aneurysms.