Risk Factors For Aneurysm Rupture Research Articles

Sex‐Dependent Manifestations of Intracranial Aneurysms

Background Intracranial aneurysms (IAs) are more common in women than in men; however, there is still limited knowledge on sex‐dependent differences regarding aneurysm location, multiplicity, rupture risk, risk factors, and histopathology. Methods This cross‐sectional, consecutive cohort study examined whether IAs differ in multiplicity, location, geometry, rupture risk, risk factors, and histology between sexes. Results We included 982 patients (714 women, 268 men) totaling 1484 IAs (1056 unruptured, 397 ruptured). A total of 363 patients (36.97%) had multiple IAs, the proportion of which was significantly higher in women. In women, the internal carotid artery (40.79%) was the most frequent location for IAs, whereas in men most were found along the anterior carotid artery territory (32.86%). Men were significantly more often diagnosed with ruptured aneurysms. Aneurysm geometry did not differ between sexes; however, ruptured aneurysms in men presented with a significantly larger neck diameter than unruptured ones. Regarding risk factors for aneurysm rupture, blood pressure control was more effective in women, whereas the effect of smoking status did not show clear sex‐dependent differences. Histologically, wall‐type classification analysis showed significantly more severe aneurysm wall types in men. Conclusion IA prevalence in women is significantly higher than in men. Women more often present with multiple IAs, whereas men were more often diagnosed with ruptured IAs. Sex‐specific differences in IA location were identified, whereas geometry of IAs did not differ between sexes. IAs in men showed a more severe histological wall type. Further research is needed to unravel the molecular mechanisms underlying these important sex‐dependent manifestations in IAs.

In Reply to Letter to the Editor Regarding “Morphologic Variations in the Circle of Willis as a Risk Factor for Aneurysm Rupture in the Anterior and Posterior Communicating Arteries”

In Reply to Letter to the Editor Regarding “Morphologic Variations in the Circle of Willis as a Risk Factor for Aneurysm Rupture in the Anterior and Posterior Communicating Arteries”

Effects of preoperative aortic tortuosity and postoperative hypertension on patient-specific hemodynamics of abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a serious dilated vascular disease. The risk factors of aneurysm rupture and postoperative blood pressure are the major clinical concerns. The purpose of this work is to analyze the hemodynamic difference between preoperative and postoperative AAA using patient-specific boundary conditions and explore the rupture risk of AAA with different torsion and to simulate the blood flow of different degrees of hypertension. A three-element Windkessel model is utilized as the outlet boundary condition. 20-sim software and self-developed user-defined functions are used to calibrate the parameters. To analyze the influence of aortic tortuosity on hemodynamics, five AAA geometries with different torsion degrees are modified and obtained. We also grade the hypertension and explore the effect of hypertension after operation. The analysis results are consistent with the patient-specific situation. The results show that stent implantation for aneurysms reduces the pressure at the lesion site and increase the speed and wall shear stress. Vessels with high torsion have lower time-averaged wall shear stress (TAWSS), higher oscillatory shear stress index (OSI) and relative retention time, and more disordered blood flow. After stent implantation, with the increase in blood pressure, TAWSS and OSI continue to increase, and the blood flow speed is also faster. AAA with high torsion is more likely to rupture. In clinical practice, attention should be paid to the degree of torsion of the lesion site. Furthermore, blood pressure should be monitored and controlled in time to prevent postoperative complications.

Possible association between β-blocker use and a risk of intracranial aneurysm rupture.

Aneurysmal subarachnoid hemorrhage is a devastating type of stroke, associated with high mortality and morbidity. One of modifiable risk factors of aneurysm rupture is hypertension, however, it is still not clear whether any particular antihypertensive drugs play a significant role in the prevention of aneurysm rupture. We decided to investigate whether there is any association between acetylsalicylic acid, α-blockers, β‑blockers, angiotensin‑converting enzyme inhibitors, angiotensin II receptor blockers, calcium channel blockers, diuretics, statins, and anticoagulants and a risk of intracranial aneurysm rupture. We retrospectively analyzed 334 patients with ruptured and unruptured intracranial aneurysm. Based on logistic regression models, we obtained unadjusted and adjusted odds ratios (ORs) of subarachnoid hemorrhage associated with the use of vasoactive medications and with indices of tortuosity. We found that β‑blocker intake was significantly related to higher tortuosity of the cerebral arteries. Also, the intake of β‑blockers (OR, 0.41; 95% CI, 0.21-0.77; P = 0.01) and statins (OR, 0.23; 95% CI, 0.05-0.68; P = 0.01) significantly decreased the risk of aneurysm rupture, a result driven by a decreased rupture risk of anterior circulation aneurysms. No such association was found for the posterior part of the cerebral circulation. Aneurysm located in the anterior cerebral circulation might be less likely to rupture if patients receive β‑blockers or statins.

Influence of size ratio on retreatment after coil embolization for unruptured bifurcation aneurysms

BackgroundAneurysm size is considered a risk factor for aneurysm rupture, and even small aneurysms may rupture, especially bifurcation aneurysms (BAs), which are occasionally detected. Therefore, we aimed to investigate the predictors of retreatment after coil embolization for unruptured BAs, with a particular focus on the absolute and relative size of the aneurysm (size ratio [SR]). MethodsTo evaluate the predictors of retreatment, patients were divided into two groups: those with and those without retreatment. Patient characteristics and radiographic assessments were compared between the groups. SR was defined as the ratio of the maximum aneurysm diameter and the average diameter of the parent artery. ResultsOverall, 181 unruptured BAs in 176 patients were investigated. The mean age of the patients was 63.8 ± 9.6 years. The mean aneurysm size and SR were 7.18 ± 2.94 mm and 2.49 ± 1.32, respectively. Further, 12 aneurysms with retreatment (6.6 %) and 169 aneurysms without retreatment were compared. In univariate analysis, SR was significantly higher in the group with retreatment (P = 0.02), but aneurysm size was not significantly different between the groups (P = 0.09). Multivariable analysis revealed that SR > 2.6 was a significant predictor of retreatment (P = 0.03; odds ratio: 10.41; 95 % confidence interval: 2.1–51.73). ConclusionsThis study showed that SR influences retreatment after coil embolization for unruptured BAs. Therefore, if the aneurysm size and parent artery diameter were small, as in cases with a large SR, meticulous follow-up after coil embolization is required to detect recurrence and recanalization.

Analysis of independent risk factors for aneurysm rupture based on carotid tortuosity index and morphological parameters of single intracranial aneurysms in anterior circulation

PurposeOur study focused on the risk factors associated with anterior circulation intracranial aneurysm (IA) rupture by examining the carotid artery (CA) tortuosity index (TI) and anterior circulation IA morphological parameters. MethodThis study conducted a retrospective analysis of clinical and imaging data from 163 patients with anterior circulation IA diagnosed by head and neck computed tomography angiography (CTA). The patients were categorized into two groups: the ruptured group (57 cases) and the unruptured group (106 cases). CA was categorized based on its location into three segments: the extracranial segment of the internal carotid artery (EICA) TI, the angle of the internal carotid artery (ICA) and the common carotid artery (CCA) TI. Measure the morphological parameters of all IA: IA length neck (L), IA height (H), aneurysm diameter width (D), the ratio of L to the mean diameter of the IA-bearing artery (SR), the ratio of H to D (AR), the angle of flow inflow (FA) and IA angle (AA). The study conducted five types of analysis to determine the risk factors for anterior circulation IA rupture. The first was an univariate analysis of the risk factors. The second was an analysis of the correlation between CA TI and IA morphological parameters. The third used multivariate logistic stepwise regression analysis to analyse independent risk factors for IA rupture. The fourth was to plot ROC curves to build a predictive model for IA rupture and calculate diagnostic thresholds. Finally, a data set from another hospital (78 cases) was used as a validation set to validate the multivariate model. ResultUnivariate analysis revealed that there were statistically significant differences (P < 0.05) in gender, EICA TI, location of IA and IA morphological parameters (FA, H, AR, L, SR), which acted as risk factors for anterior circulation IA rupture. The results of Spearman correlation analysis indicate that CCA TI is significantly correlated with SR, H and L (P < 0.05), while EICA TI is significantly correlated with FA and L (P < 0.05). The results of multivariate logistic analysis showed that FA (OR = 1.072, 95%CI = 1.04–1.10, P < 0.001), SR (OR = 4.949, 95%CI = 1.96–12.53, P = 0.001), EICA TI (OR = 1.037, 95%CI = 1.01–1.07, P = 0.003) were independent risk factors for IA rupture. The ROC curve plotting results suggest that the area under the curve (AUC) of FA is 0.860 with a diagnostic threshold of 110.1°; the AUC of SR is 0.786 with a diagnostic threshold of 1.67; the AUC of EICA TI is 0.723 with a diagnostic threshold of 28.845; the AUC of the three combined is 0.903 with a threshold of 0.480. The combined factor diagnostic model is validated according to the validation set, and the results show that the AUC (0.866) of the validation set is not much different from the AUC (0.903) of the multivariate model, and the multivariate model has a better diagnostic effect. ConclusionIn clinical practice, it is important to consider the evaluation of aneurysm rupture in combination with imaging, as FA, SR and ECIA TI are independent risk factors for IA rupture in the anterior circulation. Unlike the IA morphological parameters, EICA TI is an often overlooked extracranial parameter, but is equally important in its power to predict IA rupture. When the EICA TI exceeds 28.845, the IA has the possibility of rupture. Finally, multivariate diagnostic model are of interest when considering rupture of the anterior circulation IA.

Risk factors for aneurysm rupture among Kazakhs: findings from a national tertiary hospital

BackgroundRupture of intracranial aneurysms (RIA) leads to subarachnoid hemorrhage (SAH) with severe consequences. Although risks for RIA are established, the results vary between ethnic groups and were never studied in Kazakhstan. This study aimed to establish the risk factors of RIA in the Kazakh population. MethodsRetrospective analysis of 762 patients with single IAs, who attended the neurosurgical center from 2008 until 2018, was conducted. Demographic characteristics, such as age, sex, smoking status, and hypertension were considered. Descriptive and bivariate analyses were performed. A multivariable logistic regression model was built to identify factors correlated with RIA.ResultsThe mean age of participants was 48.49 ± 0.44 years old. The majority (68.37%) of IAs have ruptured. Of the ruptured aneurysms, 43.76% were < 6 mm, and 38.39% were located on the anterior cerebral and anterior communicating arteries (ACA). Logistic regression model indicates younger age group (16–40 years), smoking, having stage 3 hypertension, smaller IA size and its location on ACA increase the odds of rupture.ConclusionsThis study has revealed that younger, smoking patients with stage 3 arterial hypertension are at higher risk for RIA. Small aneurysms (< 6 mm) and location on ACA had increased odds of rupture, while larger aneurysms on internal carotid arteries had lower odds.

A predictive hemodynamic model based on risk factors for ruptured mirror aneurysms.

ObjectivesTo identify hemodynamic risk factors for intracranial aneurysm rupture and establish a predictive model to aid evaluation.MethodsWe analyzed the hemodynamic parameters of 91 pairs of ruptured mirror aneurysms. A conditional univariate analysis was used for the continuous variables. A conditional multivariate logistic regression analysis was performed to identify the independent risk factors. Differences where p < 0.05 were statistically significant. A predictive model was established based on independent risk factors. Odds ratios (ORs) were used to score points. The validation cohort consisted of 189 aneurysms. Receiver operating characteristic curves were generated to determine the cutoff values and area under the curves (AUCs) of the predictive model and independent risk factors.ResultsThe conditional multivariate logistic analysis showed that the low shear area (LSA) (OR = 70.322, p = 0.044, CI = 1.112–4,445.256), mean combined hemodynamic parameter (CHP) (>0.087) (OR = 3.171, p = 0.034, CI = 1.089–9.236), and wall shear stress gradient (WSSG) ratio (>893.180) (OR = 5.740, p = 0.003, CI = 1.950–16.898) were independent risk factors. A prediction model was established: 23*LSA + 1*CHP mean (>0.087: yes = 1, no = 0) + 2 * WSSG ratio (>893.180: yes = 1, no = 0). The AUC values of the predictive model, LSA, mean CHP (>0.087), and WSSG ratio (>893.180) were 0.748, 0.700, 0.654, and 0.703, respectively. The predictive model and LSA cutoff values were 1.283 and 0.016, respectively. In the validation cohort, the predictive model, LSA, CHP (>0.087), and WSSG ratio (>893.180) were 0.736, 0.702, 0.689, and 0.706, respectively.ConclusionsLSA, CHP (>0.087), and WSSG ratio (>893.180) were independent risk factors for aneurysm rupture. Our predictive model could aid practical evaluation.

Mondor disease of the breast.

<h3>Background and purpose</h3> Despite several landmark studies, the natural history of unruptured intracranial aneurysms (UIA) remains uncertain. Our aim was to identify or confirm factors predictive of rupture of UIA being observed conservatively with serial CT angiography (CTA) in a North American patient population. <h3>Methods</h3> We performed a retrospective review of patients with UIA being followed with serial CTA studies from 1999 to 2010. The following features for each aneurysm were cataloged from the official radiologic reports and CTA images: maximum diameter, growth between follow-up studies, location, multiplicity, wall calcification, intraluminal thrombus and morphology. Univariate logistic regression analysis of the potential independent risk factors for aneurysm rupture was performed. Statistically significant risk factors from the univariate analysis were then entered into a multivariate logistic regression analysis. <h3>Results</h3> 152 patients with a total of 180 UIA had at least two CTA studies. Six aneurysms in six different patients ruptured during the CTA follow-up period for an overall rupture rate of 3.3% and an annual rupture rate of 0.97%. All ruptured aneurysms were ≥9 mm. In the univariate analysis, the statistically significant predictors of aneurysm rupture were aneurysm size (p=0.003), aneurysm growth (p&lt;0.0001) and aneurysm multilobulation (p=0.001). The risk factors that remained significant following the multivariate analysis were growth (OR 55.9; 95% CI 4.47 to 700.08; p=0.002) and multilobulation (OR 17.4; 95% CI 1.52 to 198.4; p=0.022). <h3>Conclusions</h3> Aneurysm morphology and interval growth are characteristics predictive of a higher risk of subsequent rupture during conservative CTA follow-up.

Rupture Risk Assessment for Anterior Communicating Artery Aneurysms Using Decision Tree Modeling.

BackgroundAlthough anterior communicating artery (ACoA) aneurysms have a higher risk of rupture than aneurysms in other locations, whether to treat unruptured ACoA aneurysms incidentally found is a dilemma because of treatment-related complications. Machine learning models have been widely used in the prediction of clinical medicine. In this study, we aimed to develop an easy-to-use decision tree model to assess the rupture risk of ACoA aneurysms.MethodsThis is a retrospective analysis of rupture risk for patients with ACoA aneurysms from two medical centers. Morphologic parameters of these aneurysms were measured and evaluated. Univariate analysis and multivariate logistic regression analysis were performed to investigate the risk factors of aneurysm rupture. A decision tree model was developed to assess the rupture risk of ACoA aneurysms based on significant risk factors.ResultsIn this study, 285 patients were included, among which 67 had unruptured aneurysms and 218 had ruptured aneurysms. Aneurysm irregularity and vessel angle were independent predictors of rupture of ACoA aneurysms. There were five features, including size ratio, aneurysm irregularity, flow angle, vessel angle, and aneurysm size, selected for decision tree modeling. The model provided a visual representation of a decision tree and achieved a good prediction performance with an area under the receiver operating characteristic curve of 0.864 in the training dataset and 0.787 in the test dataset.ConclusionThe decision tree model is a simple tool to assess the rupture risk of ACoA aneurysms and may be considered for treatment decision-making of unruptured intracranial aneurysms.

Unruptured cerebral aneurysm risk stratification: Background, current research, and future directions in aneurysm assessment.

Background: The optimal management of unruptured cerebral aneurysms is widely debated in the medical field. Rapid technology advances, evolving understanding of underlying pathophysiology, and shifting practice patterns have made the cerebrovascular field particularly dynamic in recent years. Despite progress, there remains a dearth of large randomized studies to help guide the management of these controversial patients.Methods: We review the existing literature on the natural history of unruptured cerebral aneurysms and highlight ongoing research aimed at improving our ability to stratify risk in these patients.Results: Landmark natural history studies demonstrated the significance of size, location, and other risk factors for aneurysm rupture, but prior studies have significant limitations. We have begun to understand the underlying pathophysiology behind aneurysm formation and rupture and are now applying new tools such as flow dynamics simulations and machine learning to individualize rupture risk stratification.Conclusion: Prior studies have identified several key risk factors for aneurysmal rupture, but have limitations. New technology and research methods have enabled us to better understanding individual rupture risk for patients with unruptured cerebral aneurysms.

Letter to the Editor Regarding "Morphologic Variations in the Circle of Willis as a Risk Factor for Aneurysm Rupture in the Anterior and Posterior Communicating Arteries"

Letter to the Editor Regarding "Morphologic Variations in the Circle of Willis as a Risk Factor for Aneurysm Rupture in the Anterior and Posterior Communicating Arteries"

Letter to the Editor Regarding “Morphologic Variations in the Circle of Willis as a Risk Factor for Aneurysm Rupture in the Anterior and Posterior Communicating Arteries”

Letter to the Editor Regarding “Morphologic Variations in the Circle of Willis as a Risk Factor for Aneurysm Rupture in the Anterior and Posterior Communicating Arteries”

In Reply to Letter to the Editor Regarding ‘‘Morphological Variations in the Circle of Willis as a Risk Factor for Aneurysm Rupture in the Anterior and Posterior Communicating Arteries’’

In Reply to Letter to the Editor Regarding ‘‘Morphological Variations in the Circle of Willis as a Risk Factor for Aneurysm Rupture in the Anterior and Posterior Communicating Arteries’’

Difference in Rupture Risk Between Familial and Sporadic Intracranial Aneurysms: An Individual Patient Data Meta-analysis.

We combined individual patient data (IPD) from prospective cohorts of patients with unruptured intracranial aneurysms (UIAs) to assess to what extent patients with familial UIA have a higher rupture risk than those with sporadic UIA. For this IPD meta-analysis, we performed an Embase and PubMed search for studies published up to December 1, 2020. We included studies that (1) had a prospective study design; (2) included 50 or more patients with UIA; (3) studied the natural course of UIA and risk factors for aneurysm rupture including family history for aneurysmal subarachnoid haemorrhage and UIA; and (4) had aneurysm rupture as an outcome. Cohorts with available IPD were included. All studies included patients with newly diagnosed UIA visiting one of the study centers. The primary outcome was aneurysmal rupture. Patients with polycystic kidney disease and moyamoya disease were excluded. We compared rupture rates of familial vs sporadic UIA using a Cox proportional hazard regression model adjusted for PHASES score and smoking. We performed 2 analyses: (1) only studies defining first-degree relatives as parents, children, and siblings and (2) all studies, including those in which first-degree relatives are defined as only parents and children, but not siblings. We pooled IPD from 8 cohorts with a low and moderate risk of bias. First-degree relatives were defined as parents, siblings, and children in 6 cohorts (29% Dutch, 55% Finnish, 15% Japanese), totaling 2,297 patients (17% familial, 399 patients) with 3,089 UIAs and 7,301 person-years follow-up. Rupture occurred in 10 familial cases (rupture rate: 0.89%/person-year; 95% confidence interval [CI] 0.45-1.59) and 41 sporadic cases (0.66%/person-year; 95% CI 0.48-0.89); adjusted hazard ratio (HR) for familial cases 2.56 (95% CI 1.18-5.56). After adding the 2 cohorts excluding siblings as first-degree relatives, resulting in 9,511 patients, the adjusted HR was 1.44 (95% CI 0.86-2.40). The risk of rupture of UIA is 2.5 times higher, with a range from a 1.2 to 5 times higher risk, in familial than in sporadic UIA. When assessing the risk of rupture in UIA, family history should be taken into account.

Risk factors for intracranial aneurysm rupture in pediatric patients.

Intracranial aneurysm (IA) rupture in pediatric patients is a rare but fatal condition. Although risk factors for aneurysm rupture in adults have been well documented, they remain unknown in pediatric patients. Data for 94 pediatric patients with IAs were retrospectively analyzed. The patients were divided into ruptured and unruptured groups. Risk factors for aneurysm rupture were analyzed through univariable and multiple logistic regression analyses. Typical patients with risk factors were described. Univariable analyses showed that the unruptured group had significantly higher percentages of giant aneurysms (43.2% vs 12.3%, P = 0.002), wide-neck aneurysms (67.6% vs 29.8%, P = 0.001), and aneurysms located in the internal carotid artery (40.5% vs 3.5%, P < 0.001), while the ruptured group had significantly higher percentages of patients younger than 5years old (28.1% vs 5.4%, P = 0.013) and aneurysms located in the anterior cerebral artery (24.6% vs 5.4%, P = 0.032), posterior cerebral artery (14.0% vs 0%, P = 0.045), and distal arterial region (DAR) (46.8% vs 27.0%, P < 0.001). Multiple logistic regression analysis confirmed that age 0-5years (OR = 6.844, P = 0.042) and IAs located in the DAR (OR = 4.162, P = 0.029) were independently related to an increased risk of rupture. Wide-necked aneurysms (OR = 0.235, P = 0.047) were independently associated with a lower risk of rupture. Among pediatric patients, age younger than 5years and lesions located in the DAR are independent risk factors for IA rupture, while an IA with a wide neck acts as a protective factor.

Analysis of Morphological-Hemodynamic Risk Factors for Aneurysm Rupture Including a Newly Introduced Total Volume Ratio.

The purpose of this study was to evaluate morphological and hemodynamic factors, including the newly developed total volume ratio (TVR), in evaluating rupture risk of cerebral aneurysms using ≥7 mm sized aneurysms. Twenty-three aneurysms (11 unruptured and 12 ruptured) ≥ 7 mm were analyzed from 3-dimensional rotational cerebral angiography and computational fluid dynamics (CFD). Ten morphological and eleven hemodynamic factors of the aneurysms were qualitatively and quantitatively compared. Correlation analysis between morphological and hemodynamic factors was performed, and the relationship among the hemodynamic factors was analyzed. Morphological factors (ostium diameter, ostium area, aspect ratio, and bottleneck ratio) and hemodynamic factors (TVR, minimal wall shear stress of aneurysms, time-averaged wall shear stress of aneurysms, oscillatory shear index, relative residence time, low wall shear stress area, and ratio of low wall stress area) were statistically different between ruptured and unruptured aneurysms (p < 0.05). By simple regression analysis, the morphological factor aspect ratio and the hemodynamic factor TVR were significantly correlated (r2 = 0.602, p = 0.001). Ruptured aneurysms had complex and unstable flow. In ≥7 mm ruptured aneurysms, high aspect ratio, bottleneck ratio, complex flow, unstable flow, low TVR, wall shear stress at aneurysm, high oscillatory shear index, relative resistance time, low wall shear stress area, and ratio of low wall stress area were significant in determining the risk of aneurysm rupture.

Morphologic Variations in the Circle of Willis as a Risk Factor for Aneurysm Rupture in the Anterior and Posterior Communicating Arteries

Intracranial aneurysms are acquired abnormal vascular dilations. The most dangerous complication of a cerebral aneurysm is its rupture, with a high rate of mortality. This study aimed to determine whether there is an association between anatomic variations in the circle of Willis and ruptured aneurysms in the anterior and posterior communicating arteries. A cross-sectional study of adult patients with a diagnosis of intracranial aneurysm was carried out between March 2015 and March 2019. The patients were divided into groups of ruptured or unruptured aneurysm in the anterior and posterior communicating arteries. A total of 132 patients with anterior and posterior communicating artery aneurysms were included. The presence of anatomic variation in the circle of Willis presented a statistically significant association with ruptured aneurysms (odds ratio [OR], 2.28; 95% confidence interval [CI], 1.11-4.65; P= 0.024). There was a statistically significant difference between the presence of nonspherical aneurysm and rupture (OR, 6.9; 95% CI, 3.12-15.48; P < 0.0001). Multivariate logistic regression observed smoking (OR, 2.4; 95% CI, 1.01-5.9; P= 0.4), anterior complex variations (OR, 2.68; 95% CI, 1.01-7.18; P < 0.04), and nonspherical morphology (OR, 4.7; 95% CI, 1.93-11.45; P= 0.001) presented a statistically significant association with the rupture. Our results suggest that the studied variations of the circle of Willis and nonspherical morphology, in addition to playing a role in the development of cerebral aneurysms, may contribute to their rupture.

High-Resolution Vessel Wall Magnetic Resonance Imaging of Small Unruptured Intracranial Aneurysms.

Background: We decided to investigate whether aneurysm wall enhancement (AWE) on high-resolution vessel wall magnetic resonance imaging (HR VW-MRI) coexists with the conventional risk factors for aneurysm rupture. Methods: We performed HR VW-MRI in 46 patients with 64 unruptured small intracranial aneurysms. Patient demographics and clinical characteristics were recorded. The PHASES score was calculated for each aneurysm. Results: Of the 64 aneurysms, 15 (23.4%) showed wall enhancement on post-contrast HR VW-MRI. Aneurysms with wall enhancement had significantly larger size (p = 0.001), higher dome-to-neck ratio (p = 0.024), and a more irregular shape (p = 0.003) than aneurysms without wall enhancement. The proportion of aneurysms with wall enhancement was significantly higher in older patients (p = 0.011), and those with a history of prior aneurysmal SAH. The mean PHASES score was significantly higher in aneurysms with wall enhancement (p < 0.000). The multivariate logistic regression analysis revealed that aneurysm irregularity and the PHASES score are independently associated with the presence of AWE. Conclusions: Aneurysm wall enhancement on HR VW-MRI coexists with the conventional risk factors for aneurysm rupture.

Significance of aneurysm wall enhancement on high-resolution vessel wall magnetic resonance imaging in clinical management of patients with intracranial aneurysms.

The prevalence of intracranial aneurysms is estimated to be around 3% in the general population. Although these are often incidental findings, they potentially carry the risk of rupture, with all of the devastating consequences of SAH. Several risk factors of aneurysm rupture have been identified, including aneurysm size, irregular shape, and location. Although it is widely accepted that the risk of rupture increases with size, small aneurysms remain the cause of a significant percentage of aneurysmal SAH. Up to 30% of patients with acute aneurysmal SAH have multiple aneurysms. Determining the site of rupture in these patients can be challenging, given that the results of imaging studies and clinical symptoms are sometimes inconclusive. It would be extremely useful to identify new imaging biomarkers of aneurysm instability which could have an impact on patient management and qualification for treatment. High-resolution vessel wall magnetic resonance imaging (HR-VW MRI) opens up new possibilities for improved characterisation of intracranial vasculature. One of the most promising clinical applications of this new imaging tool is the evaluation of intracranial aneurysms. Aneurysm wall enhancement (AWE) on HR-VW MRI is believed to be a marker for wall inflammation and, potentially, for aneurysm instability. In this article, we summarise the published literature on AWE with special emphasis on its use in determining the site of rupture in the setting of acute SAH in patients with multiple aneurysms, as well as its role in identifying unruptured aneurysms which are at the greatest risk of rupture. More and larger studies are needed to definitively establish the role of AWE on HR-VW MRI in the diagnostic workup of patients with intracranial aneurysms.