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.

Successful Prophylactic Embolization of a Renal Artery Aneurysm During Pregnancy.

Renal artery aneurysms (RAA) have an increased risk of rupture during pregnancy with high mortality rates for the mother and fetus. There are many reports on the treatment of ruptured RAA during pregnancy and the Society for Vascular Surgery recommends to prophylactically treat unruptured RAA of any size in women of reproductive age to limit risk of rupture during pregnancy. However, to the best of our knowledge, there is no reported case of prophylactic treatment of unruptured RAA during pregnancy. Here we report the case of a 39-year-old G2P1 who had prophylactic endovascular coiling of an unruptured left RAA during her second trimester of pregnancy. Our case report is the first to demonstrate that unruptured RAA can be safely intervened endovascularly to prevent rupture without disrupting the pregnancy.

Aspirin and growth, rupture of unruptured intracranial aneurysms: A systematic review and meta-analysis.

OBJECTIVES: Aspirin has been suggested as a potential therapeutic strategy to prevent the growth and rupture of unruptured intracranial aneurysms (UIAs), but there is still controversy. The aim of this systematic review and meta-analysis is to determine the association between aspirin use and growth, rupture of UIAs. METHODS: We performed a systematic literature search of electronic databases to identify cohort and case-control studies investigating the relationship between aspirin use and growth or rupture of UIAs. Pooled odds ratio (OR) with corresponding 95% confidence interval (CI) were calculated using a random effects model. Heterogeneity among studies was quantified using the I2 statistic, and potential publication bias was assessed using funnel plots. Sensitivity analysis was performed to verify the robustness of the intention-to-treat results. Subgroup analysis was conducted according to the frequency of aspirin use. RESULTS: We identified 8 studies comprising 10,518 participants. The risk of bias was low to moderate. The pooled estimate showed that aspirin use was associated with a lower likelihood of growth of UIAs (OR = 0.25, 95% CI = 0.11-0.55; p = 0.0005) without statistical heterogeneity (p for Cochran Q statistic = 0.62, I2 = 0%). Likewise, aspirin intake also significant decreased 58% risk of intracranial aneurysms rupture (OR = 0.42, 95% CI = 0.29-0.60; p < 0.00001) with moderate heterogeneity (p for Cochran Q statistic = 0.005, I2 = 66%). Similar results were observed in the sensitivity analysis. Pooled OR of aspirin frequency subgroup analysis for less than or equal to 2 times per week was 0.82 (95%CI = 0.40-1.72; I2 = 0%), for at least 3 times per week to daily was 0.25 (95%CI = 0.12-053; I2 = 0%), for daily was 0.59 (95%CI: 0.47-0.74; I2 = 0%), and for unknown was 0.26 (95%CI: 0.15-0.45; I2 = 51%). CONCLUSIONS: The results of this systematic review and meta-analysis indicates a beneficial effect of aspirin on growth and rupture of UIAs.

Warning Signs in the Era of Unruptured Intracranial Aneurysms: Report on 2 Cases of Fatal Aneurysmal Hemorrhage.

INTRODUCTION: The timing of treatment remains unresolved for patients with unruptured intracranial aneurysms (UIAs) and headaches, particularly when the pain is short term, localized, and related to the aneurysm site. We lack evidence to support the notion that when a headache accompanies an aneurysm, it elevates the risk of rupture. RESULTS: We describe 2 cases of fatal subarachnoid hemorrhage in patients with a history of headache and known aneurysms. Both of these patients had good indications for treatment: a young age and an aneurysm >7 mm, and both were qualified for elective surgery. However, both patients died of fatal aneurysm ruptures before the planned surgery. CONCLUSION: These cases suggested that treatment should be started as soon as possible, when a UIA is diagnosed based on a short-term period of severe headaches or when a UIA is observed and then severe headaches appear. There is no straightforward guideline for treatment timing in these patients. However, in this era of UIAs, the significance of sentinel headaches should be reevaluated. Given the incidence of headaches in the general population and the very low risk of aneurysm rupture, there may be a tendency to neglect the role of headache as a possible warning sign.

Small Unruptured Aneurysm Verification-prevention Effect against Growth of Cerebral Aneurysm Study Using Statin.

Several basic experimental studies have demonstrated that statins have beneficial effects for intracranial aneurysm (IA). Clinical studies on unruptured IAs, however, remain limited to four retrospective studies that have reached different conclusions. This study was the first open-label, multicenter, randomized controlled trial to assess the preventive effects of atorvastatin. Patients with unruptured small saccular IAs were randomly assigned to statin and control groups. The primary endpoint was a composite of aneurysm growth of ≥0.5 mm, new bleb formation confirmed from magnetic resonance (MR) angiography, and rupture. Enrollment was prematurely terminated due to unexpectedly slow enrollment. Of 231 patients (275 target IAs), 110 patients (128 IAs) were randomly assigned to the statin group and 121 patients (147 IAs) to the control group. After excluding 22 dropout patients, 107 IAs in the 93 statin group patients and 140 IAs in the 116 control group patients were finally analyzed. No significant differences of basic characteristics were evident between groups, except for significantly higher systolic pressure in the statin group (P = 0.03). The primary endpoint occurred in 28 IAs (20.0%) in the control group and in 17 IAs (15.9%) in the statin group. No aneurysm rupture was confirmed in either group. Significant beneficial effects of statin for IAs were not demonstrated for the primary endpoint (log-rank P = 0.359). This randomized trial did not establish any preventive effects of atorvastatin for unruptured small IAs. Further studies of larger cohorts are required to clarify the efficacy of statins for patients with unruptured IAs. Clinical trial registration: UMIN000005135.

Protective effects of BP-1-102 against intracranial aneurysms-induced impairments in mice.

The development of non-invasive pharmacological therapies to prevent the progression and rupture of intracranial aneurysms (IAs) is an important field of research. This study attempts to reveal the role of BP-1-102, an oral bioavailable signal transducer and activator of transcription 3 (STAT3) inhibitor, in IA. We first constructed an IA mouse model by injecting elastase into the cerebrospinal fluid with simultaneous induction of hypertension by deoxycorticosterone acetate (DOCA) implantation. The results showed that the proportion of IA rupture in mice after BP-1-102 administration was significantly reduced, and the survival time was significantly extended. Further research showed that compared with the vehicle group, the proportion of macrophages infiltrated at the aneurysm and the expression of pro-inflammatory cytokines in the BP-1-102 administration group were significantly reduced. The contractile phenotype vascular smooth muscle cell (VSMC) specific markers, SM22α and αSMA, were significantly upregulated in the BP-1-102 group. Furthermore, we found that BP-1-102 inhibited the expression of critical proteins in the nuclear factor kappa-B and Janus kinase 2/STAT3 signalling pathways. Our study shows that BP-1-102 significantly decreases the rupture of IA, reduces the inflammatory responses and modulates the phenotype of VSMCs, suggesting that BP-1-102 could be utilised as a potential intervention drug for IA.

To clip or to coil for unruptured intracranial aneurysm?: A protocol of randomized controlled trial.

INTRODUCTION: Microsurgical clipping and endovascular coiling are the main methods against unruptured intracranial aneurysm (UIA). The craniotomy of surgical clipping may increase the risk of cerebrospinal fluid leakage and infection, damage the brain tissue, produce excessive stimulation to the nerves and blood vessels around the aneurysm, and cause the corresponding neurological deficit. Endovascular coiling could significantly reduce the mortality and disability rate than surgical clipping technique, which made endovascular coiling to become the first choice for the treatment of UIA. However, the long-term results showed attenuated favorable outcomes of coiling over clipping, so it is still in debate whether to clip or to coil. Therefore, we try to conduct a randomized, controlled, prospective trial to assess the long term safety of endovascular coiling therapy against UIA compared with microsurgical clipping technique. METHODS: Parallel-group randomization (1:1) is generated through the random number generator in Microsoft Excel 2010. In this trial, blinding to patients, physicians, and outcome assessors is not possible. Endovascular coiling or surgical clipping will be performed once for each patient in treatment group or control group, respectively. The mRS, overall mortality rate, disability rate, morbidity rate, and occurrence of a major aneurysm recurrence measured at 6 month and 1 year will be recorded. CONCLUSIONS: The findings will be helpful for the choice of endovascular coiling or surgical clipping by assessing the long term efficacy and safety of both operations against UIA. TRIAL REGISTRATION: OSF Registration number: DOI 10.17605/OSF.IO/QYE9F.

External Validation of the PHASES Score in Patients with Multiple Intracranial Aneurysms.

OBJECTIVES: This study sought to assess whether the Population, Hypertension, Age, Size, Earlier Subarachnoid Hemorrhage, Site (PHASES) score can do risk stratification of patients with multiple aneurysms (MIAs). MATERIAL AND METHODS: Patients between January 1, 2016 and January 1, 2019 were recruited retrospectively. The PHASES score was applied to assess the theoretical risk of IA rupture. For patients-level analyses, four modes of the application of the score were used: largest IA PHASES score, highest PHASES score, sum PHASES score, and mean PHASES score. RESULTS: A total of 701 patients with 1673 IAs were included in this study. At aneurysm-level analysis, the average PHASES score was 3.0 ± 3.0 points, with 2.8 ± 3.0 points and 4.1 ± 2.9 points in the unruptured and ruptured groups, respectively (p < 0.001). At the patient-level analysis, for the largest IA PHASES score, the areas under the curves (AUC) was 0.572. The discrimination performance of the largest IA PHASES score decreases as IA number increases, with AUCs were 0.597, 0.518, and 0.450 in the 2 IAs, 3 IAs and, 4 or more IAs subgroups, respectively. For highest PHASES score, sum PHASES score, and mean PHASES score, the AUCs were 0.577, 0.599, and 0.619, respectively. CONCLUSIONS: In this study, PHASES score only serve as a weak tool in decision-making settings for MIAs patients; as such, more accurate models should be developed for MIAs patients and the cumulative effect of MIA may should be considered.

Effect of combined acetylsalicylic acid and statins treatment on intracranial aneurysm rupture.

BACKGROUND: Acetylsalicylic acid (ASA) and statins have been identified as potentially reducing the risk of intracranial aneurysms (IA) rupture. We aim to determine the effect of this drugs on the risk of rupture of IA. PATIENTS AND METHODS: We performed a retrospective cohort study from a prospective database of patients with IA treated in our institution between January 2013 and December 2018. Demographics, previous oral treatments, presence of multiple aneurysms, size of aneurysm, lobulation, location and morphology of the aneurysms were recorded. Patients were dichotomized as ruptured and unruptured IA. RESULTS: A total of 408 IA were treated, of which 283 (68.6%) were in women. The median age was 53, 194 (47.5%) were ruptured IA. 38 patients (9.3%) were receiving ASA and 84 (20.6%) were receiving statins at the moment of the IA diagnosis. In the multivariable regression analysis, ASA plus statin use and multiple aneurysms were independently associated with unruptured IA (OR 5.01, 95% CI, 1.37-18.33, P = 0.015 and OR 2.72, 95% CI 1.68-4.27, P<0.001, respectively). Whereas, lobulated wall aneurysm and PComA/AComA location were inversely and independently associated with unruptured IA condition (OR 0.34, 95% CI 0.21-0.55, P<0.001 and OR 0.37, 95% CI 0.23-0.60, P<0.001, respectively). However, ASA and statins in monotherapy were not independently associated with unruptured IA condition. CONCLUSIONS: In our study population ASA plus statins treatment is independently associated with unruptured IA. Larger and prospective studies are required to explore this potential protective effect against IA rupture.

Candidate drugs for preventive treatment of unruptured intracranial aneurysms: A cross-sectional study.

BACKGROUND AND PURPOSE: Establishment of drug therapy to prevent rupture of unruptured intracranial aneurysms (IAs) is needed. Previous human and animal studies have gradually clarified candidate drugs for preventive treatment of IA rupture. However, because most of these candidates belong to classes of drugs frequently co-administered to prevent cardiovascular diseases, epidemiological studies evaluating these drugs simultaneously should be performed. Furthermore, because drugs included in the same class may have different effects in terms of disease prevention, drug-by-drug assessments are important for planning intervention trials. MATERIALS AND METHODS: We performed a cross-sectional study enrolling patients diagnosed with IAs between July 2011 and June 2019 at our institution. Patients were divided into ruptured or unruptured groups. The drugs investigated were selected according to evidence suggested by either human or animal studies. Univariate and multivariate logistic regression analyses were performed to assess the association of drug treatment with rupture status. We also performed drug-by-drug assessments of the association, including dose-response relationships, with rupture status. RESULTS: In total, 310 patients with ruptured and 887 patients with unruptured IAs were included. Multivariate analysis revealed an inverse association of statins (odds ratio (OR), 0.54; 95% confidence interval (CI) 0.38-0.77), calcium channel blockers (OR, 0.41; 95% CI 0.30-0.58), and angiotensin II receptor blockers (ARBs) (OR, 0.67; 95% CI 0.48-0.93) with ruptured IAs. Moreover, inverse dose-response relationships with rupture status were observed for pitavastatin and rosuvastatin among statins, benidipine, cilnidipine, and amlodipine among calcium channel blockers, and valsartan, azilsartan, candesartan, and olmesartan among ARBs. Only non-aspirin non-steroidal anti-inflammatory drugs were positively associated with ruptured IAs (OR, 3.24; 95% CI 1.71-6.13). CONCLUSIONS: The present analysis suggests that several types of statins, calcium channel blockers, and ARBs are candidate drugs for preventive treatment of unruptured IAs.

Location of intracranial aneurysms is the main factor associated with rupture in the ICAN population.

BACKGROUND AND PURPOSE: The ever-growing availability of imaging led to increasing incidentally discovered unruptured intracranial aneurysms (UIAs). We leveraged machine-learning techniques and advanced statistical methods to provide new insights into rupture intracranial aneurysm (RIA) risks. METHODS: We analysed the characteristics of 2505 patients with intracranial aneurysms (IA) discovered between 2016 and 2019. Baseline characteristics, familial history of IA, tobacco and alcohol consumption, pharmacological treatments before the IA diagnosis, cardiovascular risk factors and comorbidities, headaches, allergy and atopy, IA location, absolute IA size and adjusted size ratio (aSR) were analysed with a multivariable logistic regression (MLR) model. A random forest (RF) method globally assessed the risk factors and evaluated the predictive capacity of a multivariate model. RESULTS: Among 994 patients with RIA (39.7%) and 1511 patients with UIA (60.3 %), the MLR showed that IA location appeared to be the most significant factor associated with RIA (OR, 95% CI: internal carotid artery, reference; middle cerebral artery, 2.72, 2.02-3.58; anterior cerebral artery, 4.99, 3.61-6.92; posterior circulation arteries, 6.05, 4.41-8.33). Size and aSR were not significant factors associated with RIA in the MLR model and antiplatelet-treatment intake patients were less likely to have RIA (OR: 0.74; 95% CI: 0.55-0.98). IA location, age, following by aSR were the best predictors of RIA using the RF model. CONCLUSIONS: The location of IA is the most consistent parameter associated with RIA. The use of 'artificial intelligence' RF helps to re-evaluate the contribution and selection of each risk factor in the multivariate model.

Mast Cell Promotes the Development of Intracranial Aneurysm Rupture.

BACKGROUND AND PURPOSE: Inflammation has emerged as a key component of the pathophysiology of intracranial aneurysms. Mast cells have been detected in human intracranial aneurysm tissues, and their presence was associated with intramural microhemorrhage and wall degeneration. We hypothesized that mast cells play a critical role in the development of aneurysmal rupture, and that mast cells can be used as a therapeutic target for the prevention of aneurysm rupture. METHODS: Intracranial aneurysms were induced in adult mice using a combination of induced systemic hypertension and a single injection of elastase into the cerebrospinal fluid. Aneurysm formation and rupture were assessed over 3 weeks. Roles of mast cells were assessed using a mast cell stabilizer (cromolyn), a mast cell activator (C48/80), and mice that are genetically lacking mature mast cells (KitW-sh/W-sh mice). RESULTS: Pharmacological stabilization of mast cells with cromolyn markedly decreased the rupture rate of aneurysms (80% versus 19%, n=10 versus n =16) without affecting the aneurysm formation. The activation of mast cells with C48/80 significantly increased the rupture rate of aneurysms (25% versus 100%, n=4 versus n=5) without affecting the overall rate of aneurysm formation. Furthermore, the genetic deficiency of mast cells significantly prevented aneurysm rupture (80% versus 25%, n=10 versus n=8, wild-type versus KitW-sh/W-sh mice). CONCLUSIONS: These results suggest that mast cells play a key role in promoting aneurysm rupture but not formation. Stabilizers of mast cells may have a potential therapeutic value in preventing intracranial aneurysm rupture in patients.

Aspirin and Growth of Small Unruptured Intracranial Aneurysm: Results of a Prospective Cohort Study.

BACKGROUND AND PURPOSE: The role of aspirin in unruptured intracranial aneurysm (UIA) growth remains largely unknown. We aim to identify whether aspirin is associated with a lower rate of UIA growth in patients with UIA <7 mm. METHODS: This prospective cohort study consecutively enrolled patients with UIAs <7 mm with ischemic cerebrovascular disease between January 2016 and December 2019. Baseline and follow-up patient information, including the use of aspirin and blood pressure level, were recorded. Patients were considered aspirin users if they took aspirin, including standard- and low-dose aspirin, ≥3× per week. The primary end point was aneurysm growth in any direction or an indisputable change in aneurysm shape. RESULTS: Among the 315 enrolled patients, 272 patients (86.3%) underwent imaging examinations during follow-up (mean follow-up time, 19.6±12.7 months). A total of 113 patients were continuously treated with aspirin. UIA growth occurred in 31 (11.4%) patients. In the multivariate Cox analysis, specific aneurysm locations (anterior communicating artery, posterior communicating artery, or middle cerebral artery; hazard ratio, 2.89 [95% CI, 1.22-6.88]; P=0.016) and a UIA size of 5 to <7 mm (hazard ratio, 7.61 [95% CI, 3.02-19.22]; P<0.001) were associated with a high risk of UIA growth, whereas aspirin and well-controlled blood pressure were associated with a low risk of UIA growth (hazard ratio, 0.29 [95% CI, 0.11-0.77]; P=0.013 and hazard ratio, 0.25 [95% CI, 0.10-0.66]; P=0.005, respectively). The cumulative annual growth rates were as high as 40.0 and 53.3 per 100 person-years in the high-risk patients (>1 risk factor) with and without aspirin, respectively. CONCLUSIONS: Aspirin therapy and well-controlled blood pressure are associated with a low risk of UIA growth; the incidence of UIA growth in high-risk patients in the first year is high, warranting intensive surveillance in this patient group. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02846259.

Management of Unruptured Cerebral Aneurysms and Arteriovenous Malformations.

PURPOSE OF REVIEW: Unruptured intracranial aneurysms and brain arteriovenous malformations (AVMs) may be detected as incidental findings on cranial imaging. This article provides a practical approach to the management of unruptured intracranial aneurysms and unruptured brain AVMs and reviews the risk of rupture, risk factors for rupture, preventive treatment options with their associated risks, and the approach of treatment versus observation for both types of vascular malformations. RECENT FINDINGS: For unruptured intracranial aneurysms, scoring systems on the risk of rupture can help with choosing preventive treatment or observation with follow-up imaging. Although the literature provides detailed information on the complication risks of preventive treatment of unruptured intracranial aneurysms, individualized predictions of these procedural complication risks are not yet available. With observation with imaging, growth of unruptured intracranial aneurysms can be monitored, and prediction scores for growth can help determine the optimal timing of monitoring. The past years have revealed more about the risk of complications of the different treatment modalities for brain AVMs. A randomized clinical trial and prospective follow-up data have shown that preventive interventional therapy in patients with brain AVMs is associated with a higher rate of neurologic morbidity and mortality compared with observation. SUMMARY: The risk of hemorrhage from both unruptured intracranial aneurysms and brain AVMs varies depending on the number of risk factors associated with hemorrhage. For both types of vascular malformations, different preventive treatment options are available, and all carry risks of complications. For unruptured intracranial aneurysms, the consideration of preventive treatment versus observation is complex, and several factors should be included in the decision making. Overall, it is recommended that patients with unruptured asymptomatic brain AVMs should be observed.

Safety of aortic aneurysm repair 8 weeks after percutaneous coronary intervention for coronary artery disease: a cohort study.

Guidelines advice against dual antiplatelet therapy (DAPT) discontinuation less than 12 months after percutaneous coronary intervention with drug-eluting stents (DES-PCI). However, any delay of necessary surgery in patients with descending thoracic (DTA) or abdominal aortic aneurysm (AAA), treated by DES-PCI, increases the risk of aneurysm rupture/dissection. We evaluated the safety of 8-week waiting time between DES-PCI and endovascular aortic repair (EVAR). 1152 consecutive patients with coronary artery disease (CAD) needing elective DTA or AAA repair were enrolled and divided into two groups. Group A included 830 patients treated by DES-PCI for significant CAD who underwent surgery 8 weeks after implantation. Group B included 322 patients treated by DES-PCI at least 6 months before with no residual significant CAD and treated by elective EVAR. Groups were compared according to a composite of death, myocardial infarction, stent thrombosis, cerebrovascular events and bleeding. No aneurysm rupture/dissection occurred while waiting for surgery. Hospital averse events occurred in 6.2% (52/830) group A patients versus 6.5% (21/322) group B patients (p = 0.8). Mortality was 0.7% (6/830) in group A and 0.9% (3/322) in group B (p = 0.7). Multivariate predictors of events were triple vessel DES-PCI (p < 0.001), > 3 stents implanted (p < 0.001), early-generation stents (p < 0.001), diabetes insulin requiring (p = 0.01), stent diameter < 3.0 mm (p = 0.009) and total stented length > 30 mm (p = 0.02). Eight weeks of waiting after DES-PCI in addition to an adequate management of DAPT were safe in terms of cardiac morbidity and bleeding complications. No aneurysm rupture occurred in the interval before surgery.

Current management strategies for visceral artery aneurysms: an overview.

Visceral artery aneurysms (VAAs) are rare and affect the celiac artery, superior mesenteric artery, and inferior mesenteric artery, and their branches. The natural history of VAAs is not well understood as they are often asymptomatic and found incidentally; however, they carry a risk of rupture that can result in death from hemorrhage in the peritoneal cavity, retroperitoneal space, or gastrointestinal tract. Recent advances in imaging technology and its availability allow us to diagnose all types of VAA. VAAs can be treated by open surgery, laparoscopic surgery, endovascular therapy, or a hybrid approach. However, there are still no specific indications for the treatment of VAAs, and the best strategy depends on the anatomical location of the aneurysm as well as the clinical presentation of the patient. This article reviews the literature on the etiology, clinical features, diagnosis, and anatomic characteristics of each type of VAA and discusses the current options for their treatment and management.

Focal irregularities in 7-Tesla MRI of unruptured intracranial aneurysms as an indicator for areas of altered blood-flow parameters.

OBJECTIVE: In the last several decades, various factors have been studied for a better evaluation of the risk of rupture in incidentally discovered intracranial aneurysms (IAs). With advanced MRI, attempts were made to delineate the wall of IAs to identify weak areas prone to rupture. However, the field strength of the MRI investigations was insufficient for reasonable image resolution in many of these studies. Therefore, the aim of this study was to analyze findings of IAs in ultra-high field MRI at 7 Tesla (7 T). METHODS: Patients with incidentally found IAs of at least 5 mm in diameter were included in this study and underwent MRI investigations at 7 T. At this field strength a hyperintense intravascular signal can be observed on nonenhanced images with a brighter "rim effect" along the vessel wall. Properties of this rim effect were evaluated and compared with computational fluid dynamics (CFD) analyses. RESULTS: Overall, 23 aneurysms showed sufficient image quality for further evaluation. In 22 aneurysms focal irregularities were identified within this rim effect. Areas of such irregularities showed significantly higher values in wall shear stress and vorticity compared to areas with a clearly visible rim effect (p = 0.043 in both). CONCLUSIONS: A hyperintense rim effect along the vessel wall was observed in most cases. Focal irregularities within this rim effect showed higher values of the mean wall shear stress and vorticity when compared by CFD analyses. Therefore, these findings indicate alterations in blood flow in IAs within these areas.