Aneurysm Characteristics Associated with the Rupture Risk of Intracranial Aneurysms: A Self-Controlled Study

Rupture Risk Factors and Strategies for Unruptured Distal Anterior Cerebral Artery Aneurysms

BACKGROUND

Distal anterior cerebral artery (dACA) aneurysms are rare. Ruptured dACA aneurysms typically present with subarachnoid hemorrhage in conjunction with intracerebral hematoma and cause neurological deterioration. This study aimed to determine their risk of rupture and examine associated factors.

METHODS

We retrospectively analyzed patients with dACA aneurysms to compare patient and aneurysm characteristics between ruptured and unruptured aneurysms. Clinical outcome was used the modified Rankin scale. Univariate analyses were performed to identify rupture risk factors.

RESULTS

One hundred three patients with dACA aneurysms were examined (51 ruptured and 52 unruptured). The median aspect ratio of ruptured and unruptured aneurysms was 1.69 and 1.22, respectively (P < 0.01). The median maximum diameter of ruptured and unruptured aneurysms was 5.2 and 3.1 mm, respectively (P < 0.01). The median size ratio of ruptured and unruptured aneurysms was 3.32 and 2.17, respectively (P < 0.01). Maximum diameter was <5 mm in 45.2% of ruptured dACA aneurysms. dACA aneurysm, showing size ratio >2.4 and aspect ratio >1.4, had ruptured in 71.4% and 78.6%, respectively. We suggested that these are the threshold of size ratio and aspect ratio for rupture of dACA aneurysms. A total percentatge of 78.1% of aneurysms with aspect ratio >1.4 and size ratio >2.4 had ruptured.

CONCLUSIONS

Distal anterior cerebral artery (dACA) aneurysms may rupture, even when small. We found a significant difference between ruptured and unruptured aneurysms with respect to maximum diameter, aspect ratio, and size ratio. Treatment for small aneurysms should be considered based on size ratio and aspect ratio, not just size.

Plasma levels of CD36 and glutathione as biomarkers for ruptured intracranial aneurysm

Evidence has proved that intracranial aneurysm (IA) formation and rupture might be closely related to inflammatory response and oxidative stress. Our objective was to evaluate the potential of CD36 and glutathione (GSH) as biomarkers for IA. In this study, the enzyme-linked immunosorbent assay was used to measure the plasma levels of CD36 and GSH in 30 IA patients and 30 healthy controls. Then, correlation analysis, receiver operating characteristic (ROC) curve, and logistic regression analysis were performed. The results showed that the plasma level of CD36 in IA patients was significantly higher than that in the control group (P < 0.0001), and plasma GSH was significantly lower compared with that in the control group (P < 0.0001). ROC analysis showed that CD36 and GSH had high sensitivity (90.0 and 96.6%) and specificity (96.6 and 86.6%) for IA diagnosis. The combined sensitivity and specificity achieved were 100 and 100%, respectively. The plasma levels of CD36 and GSH did not show a significant correlation with age, the Glasgow Coma Scale, Hunter-Hess score, aneurysm size, aneurysm height, aneurysm neck, and aspect ratio. The AUC of the logistic regression model based on CD36 and GSH was 0.505. Our results suggested that the combination of plasma CD36 and GSH could serve as potential biomarkers for IA rupture.

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

PURPOSE

Our 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.

METHOD

This 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.

RESULT

Univariate 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.

CONCLUSION

In 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.

How does the recurrence-related morphology characteristics of the Pcom aneurysms correlated with hemodynamics?

Introduction

Posterior communicating artery (Pcom) aneurysm has unique morphological characteristics and a high recurrence risk after coil embolization. This study aimed to evaluate the relationship between the recurrence-related morphology characteristics and hemodynamics.

Method

A total of 20 patients with 22 Pcom aneurysms from 2019 to 2022 were retrospectively enrolled. The recurrence-related morphology parameters were measured. The hemodynamic parameters were simulated based on finite element analysis and computational fluid dynamics. The hemodynamic differences before and after treatment caused by different morphological features and the correlation between these parameters were analyzed.

Result

Significant greater postoperative inflow rate at the neck (Qinflow), relative Qinflow, inflow concentration index (ICI), and residual flow volume (RFV) were reported in the aneurysms with wide neck (>4 mm). Significant greater postoperative RFV were reported in the aneurysms with large size (>7 mm). Significant greater postoperative Qinflow, relative Qinflow, and ICI were reported in the aneurysms located on the larteral side of the curve. The bending angle of the internal carotid artery at the initiation of Pcom (αICA@PCOM) and neck diameter had moderate positive correlations with Qinflow, relative Qinflow, ICI, and RFV.

Conclusion

The morphological factors, including aneurysm size, neck diameter, and αICA@PCOM, are correlated with the recurrence-inducing hemodynamic characteristics even after fully packing. This provides a theoretical basis for evaluating the risk of aneurysm recurrence and a reference for selecting a surgical plan.

Study of Typical Ruptured and Unruptured Intracranial Aneurysms Based on Fluid-Structure Interaction

BACKGROUND

Most intracranial aneurysms (IAs) will be abnormal bulges on the walls of intracranial arteries that result from the dynamic interaction of geometric morphology, hemodynamics, and pathophysiology. Hemodynamics plays a key role in the origin, development, and rupture of IAs. In the past, hemodynamic studies of IAs were mostly based on the rigid wall hypothesis of computational fluid dynamics, and the influence of arterial wall deformation was ignored. We used fluid-structure interaction (FSI) to study the features of ruptured aneurysms, because it can solve this problem very well and the simulation will be more realistic.

METHODS

A total of 12 IAs, 8 ruptured and 4 unruptured, at the middle cerebral artery bifurcation were studied using FSI to better identify the characteristics of ruptured IAs. We studied the differences in the hemodynamic parameters, including the flow pattern, wall shear stress (WSS), oscillatory shear index (OSI), and displacement and deformation of the arterial wall.

RESULTS

Ruptured IAs had a larger low WSS area and more complex, concentrated, and unstable flow. Also, the OSI was higher. In addition, the displacement deformation area at the ruptured IA was more concentrated and larger.

CONCLUSIONS

A large aspect ratio; a large height/width ratio; complex, unstable, and concentrated flow patterns with small impact areas; a large low WSS region; large WSS fluctuation, high OSI; and large displacement of the aneurysm dome could be risk factors associated with aneurysm rupture. If similar cases are encountered when simulation is used in the clinic, priority should be given to diagnosis and treatment.

The rupture risk factors of mirror intracranial aneurysms: A systematic review and meta-analysis based on morphological and hemodynamic parameters

OBJECTIVE

Intracranial aneurysms (IAs) are a prevalent form of vascular disease that can lead to fatal outcomes upon rupture. Mirror intracranial aneurysms (MIAs) are a specific type of multiple aneurysms situated symmetrically on both sides of the parent arteries. The factors contributing to the risk of MIA rupture, based on morphological and hemodynamic parameters, are currently controversial. Thus, we conducted a systematic review and meta-analysis to investigate the risk factors for MIA rupture.

METHODS

The study performed an electronic search of Chinese and English databases, including China national Knowledge Infrastructure (CNKI), WanFang, VIP, PubMed, Embase, Web of Science, Scopus, and the Cochrane Library databases, and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The morphological parameters (IA size, aspect ratio [AR], size ratio [SR], bottleneck factor [BNF], height-width ratio [HWR], irregular shape) and hemodynamic parameters (wall shear stress [WSS], low WSS area [LSA], oscillatory shear index [OSI]) were analyzed for their significance in determining the risk of MIA rupture.

RESULTS

The analysis comprised 18 retrospective studies involving 647 patients, with a total of 1294 IAs detected, including 605 ruptured and 689 unruptured. The meta-analysis revealed that IA size, AR, SR, and irregular shape exhibited significant differences between the ruptured and unruptured groups, but HWR did not. In terms of hemodynamic parameters, WSS, OSI, and LSA were found to have significant differences between the two groups.

CONCLUSIONS

Our results demonstrate that larger IAs, higher AR, SR, and BNF are associated with a higher risk of rupture in patients with MIAs, regardless of their location. there is no significant difference in HWR between the ruptured and unruptured groups. These preliminary findings offer valuable insights for clinical decision-making and a more comprehensive comprehension of the current MIA status. Nevertheless, larger and multi-center studies are indispensable for corroborating these findings. Systematic review registration: https://www.crd.york.ac.uk/prospero/ identifier: CRD42022345587.

Study and modeling of the thrombosis of small cerebral aneurysms, with and without flow diverter, by the lattice Boltzmann method

BACKGROUND AND OBJECTIVE

Small cerebral aneurysms are currently commonly treated non-invasively by flow diverter device. These stents lead to thrombotic occlusion of the aneurysm soon after their placement. The purpose of this work is to model clotting into intracranial aneurysms with and without stents, using a non-Newtonian of blood behavior, and to investigate the importance of stent to generate desired thrombus in intracranial aneurysms.

METHOD

The description of blood flow is made by the Boltzmann lattice equations, while thrombosis is modeled by the "fluid age" model. The lattice Boltzmann method is a computational technique for simulating fluid dynamics. The method is based on a mesoscopic approach, where the fluid is represented by a set of particles that move and interact on a grid. The model for blood coagulation is described by lattice Boltzmann Method, and it doesn't take into account the complicated coagulation pathway, this main idea is developed using the model of residence time of blood: all fluid in the domain is assumed to be capable of clotting, given enough time. The fluid age is measured by a passive scalar using a transport equation, and the node coagulates if the fluid age increases enough. Three small aneurysms of different sizes and shapes with three stents of various porosities were used to test the ability of the model to predict thrombosis. The "occlusion rate" parameter is used to assess the effectiveness of the flow diverter device.

RESULTS

For the large aspect ratio factor, the occlusion is: 91% for flow diverter devise with seven struts. For medium aspect ratio, a rate of 80% is achieved. An occlusion rate of slightly more than 30% is obtained for very small aneurysms with low aspect ratio. The Newtonian model underestimates the volume of thrombosis generated. The difference in the prediction of the thrombosis volume between the Newtonian and no-Newtonian Carreau-Yasuda models is approximately 10%.

CONCLUSION

The occlusion rate is proportional to the aspect ratio form factor. For the large and medium aspect ratio factors, the occlusion is satisfactory. Concerning very small aneurysms with low aspect ratio, aneurysm occlusion is low. This rate can be improved to almost complete occlusion if the flow diverter device is doubled. The generality of the model suggests its extensibility toward any other type of thrombosis (stenosis, thrombosis in aortic aneurysms).

A deep-learning method for the end-to-end prediction of intracranial aneurysm rupture risk

It is critical to accurately predict the rupture risk of an intracranial aneurysm (IA) for timely and appropriate treatment because the fatality rate after rupture is 50 % . Existing methods relying on morphological features (e.g., height-width ratio) measured manually by neuroradiologists are labor intensive and have limited use for risk assessment. Therefore, we propose an end-to-end deep-learning method, called TransIAR net, to automatically learn the morphological features from 3D computed tomography angiography (CTA) data and accurately predict the status of IA rupture. We devise a multiscale 3D convolutional neural network (CNN) to extract the structural patterns of the IA and its neighborhood with a dual branch of shared network structures. Moreover, we learn the spatial dependence within the IA neighborhood with a transformer encoder. Our experiments demonstrated that the features learned by TransIAR are more effective and robust than handcrafted features, resulting in a 10 % - 15 % improvement in the accuracy of rupture status prediction.

Reproducibility of the computational fluid dynamic analysis of a cerebral aneurysm monitored over a decade

Computational fluid dynamics (CFD) simulations are increasingly utilised to evaluate intracranial aneurysm (IA) haemodynamics to aid in the prediction of morphological changes and rupture risk. However, these models vary and differences in published results warrant the investigation of IA-CFD reproducibility. This study aims to explore sources of intra-team variability and determine its impact on the aneurysm morphology and CFD parameters. A team of four operators were given six sets of magnetic resonance angiography data spanning a decade from one patient with a middle cerebral aneurysm. All operators were given the same protocol and software for model reconstruction and numerical analysis. The morphology and haemodynamics of the operator models were then compared. The segmentation, smoothing factor, inlet and outflow branch lengths were found to cause intra-team variability. There was 80% reproducibility in the time-averaged wall shear stress distribution among operators with the major difference attributed to the level of smoothing. Based on these findings, it was concluded that the clinical applicability of CFD simulations may be feasible if a standardised segmentation protocol is developed. Moreover, when analysing the aneurysm shape change over a decade, it was noted that the co-existence of positive and negative values of the wall shear stress divergence (WSSD) contributed to the growth of a daughter sac.

Protocol and Preliminary Results of the Establishment of Intracranial Aneurysm Database for Artificial Intelligence Application Based on CTA Images

Background and Purpose

Unruptured intracranial aneurysms (UIAs) are increasingly being detected in clinical practice. Artificial intelligence (AI) has been increasingly used to assist diagnostic techniques and shows encouraging prospects. In this study, we reported the protocol and preliminary results of the establishment of an intracranial aneurysm database for AI application based on computed tomography angiography (CTA) images.

Methods

Through a review of picture archiving and communication systems, we collected CTA images of patients with aneurysms between January 2010 and March 2021. The radiologists performed manual segmentation of all diagnosed aneurysms on subtraction CTA as the basis for automatic aneurysm segmentation. Then, AI will be applied to two stages of aneurysm treatment, namely, automatic aneurysm detection and segmentation model based on the CTA image and the aneurysm risk prediction model.

Results

Three medical centers have been included in this study so far. A total of 3,190 cases of CTA examinations with 4,124 aneurysms were included in the database. All identified aneurysms from CTA images that enrolled in this study were manually segmented on subtraction CTA by six readers. We developed a structure of 3D-Unet for aneurysm detection and segmentation in CTA images. The algorithm was developed and tested using a total of 2,272 head CTAs with 2,938 intracranial aneurysms. The recall and false positives per case (FP/case) of this model for detecting aneurysms were 0.964 and 2.01, and the Dice values for aneurysm segmentation were 0.783.

Conclusion

This study introduces the protocol and preliminary results of the establishment of the intracranial aneurysm database for AI applications based on CTA images. The establishment of a multicenter database based on CTA images of intracranial aneurysms is the basis for the application of AI in the diagnosis and treatment of aneurysms. In addition to segmentation, AI should have great potential for aneurysm treatment and management in the future.

Identification of ruptured intracranial aneurysms using the aneurysm-specific prediction score in patients with multiple aneurysms with subarachnoid hemorrhages- a Chinese population based external validation study

Background

For patients with aneurysmal subarachnoid hemorrhages (SAHs) and multiple intracranial aneurysms (MIAs), a simple and fast imaging method that can identify ruptured intracranial aneurysms (RIAs) may have great clinical value. We sought to use the aneurysm-specific prediction score to identify RIAs in patients with MIAs and evaluate the aneurysm-specific prediction score.

Methods

Between May 2018 and May 2021, 134 patients with 290 MIAs were retrospectively analyzed. All patients had an SAH due to IA rupture. CT angiography (CTA) was used to assess the maximum diameter, shape, and location of IAs to calculate the aneurysm-specific prediction score. Then, the aneurysm-specific prediction score was applied to RIAs in patients with MIAs.

Results

The IAs with the highest aneurysm-specific prediction scores had not ruptured in 17 (12.7%) of the 134 patients with 290 MIAs. The sensitivity, specificity, false omission rate, diagnostic error rate, and diagnostic accuracy of the aneurysm-specific prediction score were higher than those of the maximum diameter, shape, and location of IAs.

Conclusions

The present study suggests that the aneurysm-specific prediction score has high diagnostic accuracy in identifying RIAs in patients with MIAs and SAH, but that it needs further evaluation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02727-w.

Could A1 Aplasia or Hypoplasia Affect the Morphology and Rupture Risk of Anterior Communicating Artery Aneurysm?

Objective

Anterior communicating artery (Acom) aneurysm is one of the most common intracranial aneurysms, constituting approximately 30–35% of all aneurysm formation in the brain. Anatomically, the H-complex (the anatomic morphology of both A1 to A2 segments) is thought to affects the nature of the Acom aneurysm due to its close relationship with the hemodynamics of the vessel. Therefore, we investigated the relative risk factors of aneurysmal rupture, especially focusing on H-complex morphology of the Acom.

Methods

From January 2016 to December 2020, a total of 209 patients who underwent surgery, including clipping and coiling for Acom aneurysm in our institution were reviewed. There were 102 cases of ruptured aneurysm and 107 cases of unruptured aneurysm. The baseline morphology of aneurysms was investigated and the relationship between the H-complex and the clinical characteristics of patients with Acom aneurysms was assessed.

Results

Of the 209 patients, 109 patients (52.1%) had symmetrical A1, 79 patients (37.8%) had unilateral hypoplastic A1, and 21 patients (10.0%) had aplastic A1. The hypoplastic A1 group and the aplastic A1 group were grouped together as unilateral dominancy of A1, and were compared with the symmetrical A1 group. There was no significant difference in demographic characteristics and radiological findings of Acom aneurysms between two groups. However, when dichotomizing the patients into ruptured cases and unruptured cases, unilateral dominance of the A1 segment was associated with aneurysmal rupture with statistical significance (p=0.011).

Conclusion

These results suggest that the unilateral dominance of the A1 segment does not have a significant effect on the morphology of Acom aneurysms, but contributes to aneurysmal rupture. Thus, we can better understand the effects of hemodynamics on Acom aneurysm.

Morphological and Hemodynamic Characteristics Associated With the Rupture of Multiple Intracranial Aneurysms

Background and Purpose

The objective of this study was to identify the morphological and hemodynamic factors associated with the rupture of multiple intracranial aneurysms regardless of patient-related factors and establish a statistical model for aneurysm rupture risk assessment.

Methods

The digital subtraction angiography (DSA) data of 104 mirror intracranial aneurysms in 52 consecutive patients were retrospectively analyzed in this study. 21 morphological parameters and hemodynamic parameters were calculated by 3-dimensional reconstruction and computational fluid dynamics (CFD) simulation. Significant differences (p < 0.05) between the two groups were subsequently tested with the multivariate logistic regression to identify the independent risk factors. A prediction model was established based on the independent risk factors. The receiver operating characteristics (ROCs) were generated to estimate the prediction performance. A cohort of patients with multiple intracranial aneurysms admitted in our institute from January 2021 to October 2021 was introduced to verify the value of the model.

Results

Significant differences between the ruptured and unruptured aneurysms were found in 15 out of 19 parameters. Bleb formation, neck width, and size ratio were independent factors in the multivariate logistic regression. A prediction model based on the three independent risk factors was established: Odds = −1.495 – 0.707 × _(Neckwidth) + 3.061 × _{(Blebformation)} + 2.1 × _(SR) (bleb formation: Yes = 1, No = 0). The area under the curve (AUC) value of the model was 0.901. In the validation cohort, the prediction model showed satisfying performance in assessing multiple aneurysm rupture risk with a sensitivity of 100% and specificity of 88.46%.

Conclusion

Bleb formation, neck width, and size ratio were independently associated with aneurysm rupture status. The prediction model may help in identifying the aneurysm with high rupture risk.

U-Shaped Association of Aspect Ratio and Single Intracranial Aneurysm Rupture in Chinese Patients: A Cross-Sectional Study

Background: Previous studies have analyzed the association of aspect ratio (AR) on the ruptured intracranial aneurysm (IA), but the findings are inconclusive and controversial. Therefore, the study aimed to derive a more detailed estimation of this association between AR and ruptured IA in Chinese IA patients. Methods: The present work was a cross-sectional study. We retrospectively collected 1,588 Chinese patients with a single IA from January 2010 to November 2017. The relationship was examined between AR at diagnosis and ruptured IA. Covariates included data of demographics, morphological parameters, lifestyle habits, clinical features, and comorbidities. Binary logistic regression and two-piecewise linear models were used to analyze independent associations of AR with ruptured IA. Results: The results suggest that the association between AR and IA rupture was U-shaped. In the AR range of 1.08-1.99, the prevalence of IA rupture was 13% lower for each 0.1-unit increment in AR [odds ratio 0.87, 95% confidence interval (CI) 0.80-0.98]. Conversely, for every 0.1-unit increase in AR, the prevalence of IA rupture increased by ~3% (odds ratio 1.03, 95% CI 1.01-1.06) in the AR range of 3.42-4.08. Conclusion: The relationship between AR and ruptured IA was U-shaped, with the negative association at AR of 1.08-1.99 and positive association at AR of 3.42-4.08.

Hemodynamic and Morphological Parameters of Ruptured Mirror Posterior Communicating Artery Aneurysms

Objective: Morphological and hemodynamic parameters might predict rupture of intracranial aneurysms (IAs). A practical model for the study is patients with ruptured mirror IAs in which one is ruptured and the other is unruptured. Although there have been analyses of the morphology and hemodynamics of ruptured mirror posterior communicating artery aneurysms (PComAAs), the sample sizes in these studies were small and only considered hemodynamics or morphological characters. Therefore, this study aimed to investigate the morphological and hemodynamic parameters associated with ruptured mirror PComAAs. Methods: We considered 72 patients with ruptured mirror PComAAs using computational fluid dynamics (CFDs). Ruptured mirror PComAAs were divided into ruptured and unruptured groups. Fourteen morphological and eight hemodynamic parameters were calculated and compared. Significant parameters were analyzed by the multivariate logistic regression to identify independent risk factors. Receiver operating characteristic (ROC) analysis was performed, and the area under the ROC curve (AUC) was calculated for all independent risk factors to determine the predictability and identify the optimal threshold. Results: Four hemodynamic and three morphological parameters were significantly different between ruptured and unruptured groups: normalized wall shear stress (NWSS), mean WSS, low wall shear WSS area (LSA%), size, aspect ratio (AR), size ratio (SR), and inflow angle (IA). Multivariate logistic regression analysis showed that AR, SR, NWSS, mean WSS, and LSA% were all independent factors significantly associated with PComAAs rupture. The ROC analysis for independent risk factors indicated that AR (0.751), NWSS (0.755), mean WSS (0.69), and LSA (0.778) had merely acceptable AUC values. Only SR (0.803) had a high acceptable AUC value. The threshold value of SR was 1.96. Conclusions: SR (>1.96) was the most significant parameter associated with IA rupture, whereas AR, NWSS, mean WSS, and LSA independently characterized the status of IA rupture.

Risk Factors of Anterior Circulation Intracranial Aneurysm Rupture: Extracranial Carotid Artery Tortuosity and Aneurysm Morphologic Parameters

Background: This study was conducted to explore the risk factors of anterior circulation intracranial aneurysm rupture based on extracranial carotid artery (ECA) tortuosity.

Methods: This retrospective study, conducted from January 1, 2017, to March 1, 2021, collected and reviewed the clinical and imaging data of 308 patients with anterior circulation intracranial aneurysm [133 (43.2%) patients in the ruptured aneurysm group; 175 (56.8%) patients in the unruptured aneurysm group]. Computed tomography angiography (CTA) of the head and neck was used to determine the ECA tortuosity (normal, simple tortuosity, kink, coil) and the morphologic parameters of the aneurysms. The relationship of aneurysm rupture to ECA tortuosity and the morphologic parameters were analyzed.

Results: After univariate analysis, kink, angle of flow inflow (FA), aspect ratio (AR), aneurysm length (L), the distance from the tortuosity to the aneurysm (distance), and size ratio (SR) were significantly correlated with anterior circulation intracranial aneurysm rupture (p < 0.05). Spearman correlation analysis showed that ECA tortuosity was correlated with FA and SR (p < 0.05). Multiple logistic analyses showed that FA [odds ratio (OR), 1.013; 95% CI, 1.002–1.025], SR (OR, 1.521; 95% CI, 1.054–2.195), and kink (OR, 1.823; 95% CI, 1.074–3.096) were independently associated with aneurysm rupture.

Conclusion: Study results suggest that FA, SR, and ECA kink were independent risk factors associated with anterior circulation intracranial aneurysm rupture.

Relationship between peroxisome proliferator-activated receptor-γ mRNA expression and intracranial aneurysm rupture

It has been reported that the normal adults can suffer from an intracranial aneurysm (IA) that might present the risk of rupture and cause the subarachnoid hemorrhage. Peroxisome proliferator-activated receptor-γ (PPAR-γ) as a nuclear hormone receptor has been identified to involve in the progress of the formation and rupture of IAs. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect PPAR-γmRNA expression in the macrophages of the patients with IAs. The information including fasting blood glucose (FBG), interleukin-6 (IL-6), and systolic blood pressure (SBP) were collected. The aneurysm parameters of all the participants were obtained through the cerebral angiography. Establishing the receiver-operating characteristic curve (ROC curve) evaluated the clinical significances of PPAR-γmRNA for IAs rupture. In this study, we observed that the rupture of IAs was caused by the maximum height of aneurysm ⩾7 mm, the location of aneurysm in posterior communicating artery (PCOM) or anterior communicating artery (ACOM), and the increase of aneurysm size ratio (SR). The levels of SBP and IL-6 in the rupture group were higher than those in the unrupture group, and PPAR-γmRNA expression in the rupture group was also significantly reduced. In addition, heavy drinking was statistically significant between the ruptured and unruptured groups. There was no significant difference in serum FBG level between the two groups. The evidences of this study showed that PPAR-γmRNA was negatively correlated with SBP, SR, and IL-6 levels in rupture group, respectively. The AUC of PPAR-γmRNA in ROC curve was 0.867, indicating that the change of PPAR-γmRNA level had obvious effect on IAs rupture. The aim of this study was to evaluate the potential of PPAR-γ in macrophages to prevent IAs rupture.

Asymptomatic complete distal abdominal aortic occlusion with initial presentation of ruptured intracranial aneurysm

Aortoilliac occlusive disease is occlusive atherosclerosis disease involving the distal aorta and bifurcation of iliac arteries and it is a subtype of peripheral arterial disease. Total occlusion of the abdominal aorta is a rare occurrence with an incidence of 3% -8.5% among the aortoiliac occlusive disease patients. We present a case of a 53 years old patient with a background history of hypertension and ex intravenous drug abuser with negative retroviral screening status, with no previous complaints who was brought to the Emergency Department with sudden onset of altered sensorium and 1 episode of seizure. Computed tomography angiogram of the brain showed a ruptured anterior communicating artery aneurysm. Diagnostic conventional angiogram of the brain was planned; however, difficulty was encountered during bilateral femoral artery cannulation with the abrupt termination of bilateral common iliac arteries. Computed tomography angiogram of the abdomen showed incidental finding of total occlusion of the abdominal aorta. As a conclusion, total occlusion of abdominal aorta secondary to aortoiliac occlusive disease with an associated intracranial aneurysm is never reported in the literature to date. This case highlights the possibility of association in between these two conditions which may benefit from further research.

Shape related features of intracranial aneurysm are associated with rupture status in a large Chinese cohort

BACKGROUND

To investigate the prevalence of small ruptured saccular intracranial aneurysms (sIA) in a Chinese cohort and to identify factors associated with rupture status of sIAs.

METHODS

Consecutive patients with confirmed sIAs by DSA from January 2015 to July 2019 were included. Demographic and aneurysmal features, including maximal diameter, location, irregularity (lobulated or with blebs), and aspect ratio (AR, defined as height divided by neck width) were recorded and analyzed. Mixed effect logistic regression was used in multivariate analysis.

RESULTS

We analyzed 1514 sIAs in a Chinese cohort of 1216 patients, including 651 ruptured and 863 unruptured sIAs. Median aneurysm size was 5.7 mm for ruptured aneurysms, with 66.1% <7 mm in maximal diameter, and 40.2% measuring <5 mm. The median PHASES score of ruptured sIAs was 5. In multivariate analysis, male sex, hypertension, locations other than the internal carotid artery, irregularity (lobulated or with blebs), and higher AR were independently associated with rupture status (OR for irregularity, 2.88, 95% CI 2.20 to 3.77, p<0.001; OR for AR, 1.12, 95% CI 1.01 to 1.24, p=0.036). However, maximal diameter was not significantly associated with rupture status (p=0.72).

CONCLUSIONS

In this cohort, ruptured sIAs were frequently smaller than 7 mm. Shape related features, such as irregularity and higher AR, were associated with the ruptured status of sIAs, irrespective of diameter. PHASES seems to be inadequate in sIA risk stratification. Shape related parameters may be further investigated in prospective studies.

Tobacco use and age are associated with different morphologic features of anterior communicating artery aneurysms

We present a cohort of patients with anterior communicating artery (ACoA) aneurysms to investigate morphological characteristics and clinical factors associated with rupture of the aneurysms. 505 patients with ACoA aneurysms were identified at the Brigham and Women's Hospital and Massachusetts General Hospital between 1990 and 2016, with available CT angiography (CTA). Three-dimensional (3D) reconstructions were performed to evaluate aneurysmal morphologic features, including location, projection, irregularity, the presence of daughter dome, height, height/width ratio, and relationships between surrounding vessels. Patient risk factors assessed included patient age, sex, tobacco use, alcohol use, and family history of aneurysms and aneurysmal subarachnoid hemorrhage. Logistic regression was used to build a predictive ACoA score for rupture. Morphologic features associated with ruptured ACoA aneurysms were the presence of a daughter dome (OR 21.4, 95% CI 10.6-43.1), smaller neck diameter (OR 0.55, 95% CI 0.42-0.71), larger aspect ratio (OR 3.57, 95% CI 2.05-6.24), larger flow angle (OR 1.03, 95% CI 1.02-1.05), and smaller ipsilateral A2-ACoA angle (OR 0.98, 95% CI 0.97-1.00). Tobacco use was predominantly associated with morphological factors intrinsic to the aneurysm that were associated with rupture while younger age was also associated with morphologic features extrinsic to the aneurysm that were associated with rupture. The ACoA score had good predictive capacity for rupture with AUC = 0.92 using the 0.632 bootstrap cross-validation for correction of overfitting bias. Ruptured ACoA aneurysms were associated with morphological features that are simple to assess using a simple scoring system. Tobacco use and younger age were predominantly associated with intrinsic and extrinsic morphological features characteristic of rupture, respectively.

Morphological variables associated with ruptured basilar tip aneurysms

Morphological factors of intracranial aneurysms and the surrounding vasculature could affect aneurysm rupture risk in a location specific manner. Our goal was to identify image-based morphological parameters that correlated with ruptured basilar tip aneurysms. Three-dimensional morphological parameters obtained from CT-angiography (CTA) or digital subtraction angiography (DSA) from 200 patients with basilar tip aneurysms diagnosed at the Brigham and Women's Hospital and Massachusetts General Hospital between 1990 and 2016 were evaluated. We examined aneurysm wall irregularity, the presence of daughter domes, hypoplastic, aplastic or fetal PCoAs, vertebral dominance, maximum height, perpendicular height, width, neck diameter, aspect and size ratio, height/width ratio, and diameters and angles of surrounding parent and daughter vessels. Univariable and multivariable statistical analyses were performed to determine statistical significance. In multivariable analysis, presence of a daughter dome, aspect ratio, and larger flow angle were significantly associated with rupture status. We also introduced two new variables, diameter size ratio and parent-daughter angle ratio, which were both significantly inversely associated with ruptured basilar tip aneurysms. Notably, multivariable analyses also showed that larger diameter size ratio was associated with higher Hunt-Hess score while smaller flow angle was associated with higher Fisher grade. These easily measurable parameters, including a new parameter that is unlikely to be affected by the formation of the aneurysm, could aid in screening strategies in high-risk patients with basilar tip aneurysms. One should note, however, that the changes in parameters related to aneurysm morphology may be secondary to aneurysm rupture rather than causal.

In Vitro Assessment of Flow Variability in an Intracranial Aneurysm Model Using 4D Flow MRI and Tomographic PIV

Aneurysm rupture has been suggested to be related to aneurysm geometry, morphology, and complex flow activity; therefore, understanding aneurysm-specific hemodynamics is crucial. 4D Flow MRI has been shown to be a feasible tool for assessing hemodynamics in intracranial aneurysms with high spatial resolution. However, it requires averaging over multiple heartbeats and cannot account for cycle-to-cycle hemodynamics variations. This study aimed to assess cycle-to-cycle flow dynamics variations in a patient-specific intracranial aneurysm model using tomographic particle image velocimetry (tomo-PIV) at a high image rate under pulsatile flow conditions. Time-resolved and time-averaged velocity flow fields within the aneurysm sac and estimations of wall shear stress (WSS) were compared with those from 4D Flow MRI. A one-way ANOVA showed a significant difference between cardiac cycles (p value < 0.0001); however, differences were not significant after PIV temporal and spatial resolution was matched to that of MRI (p value 0.9727). This comparison showed the spatial resolution to be the main contributor to assess cycle-to-cycle variability. Furthermore, the comparison with 4D Flow MRI between velocity components, streamlines, and estimated WSS showed good qualitative and quantitative agreement. This study showed the feasibility of patient-specific in-vitro experiments using tomo-PIV to assess 4D Flow MRI with high repeatability in the measurements.

Age and morphology of posterior communicating artery aneurysms

Risk of intracranial aneurysm rupture could be affected by geometric features of intracranial aneurysms and the surrounding vasculature in a location specific manner. Our goal is to investigate the morphological characteristics associated with ruptured posterior communicating artery (PCoA) aneurysms, as well as patient factors associated with the morphological parameters. Three-dimensional morphological parameters in 409 patients with 432 PCoA aneurysms diagnosed at the Brigham and Women’s Hospital and Massachusetts General Hospital between 1990 and 2016 who had available CT angiography (CTA) or digital subtraction angiography (DSA) were evaluated. Morphological parameters examined included aneurysm wall irregularity, presence of a daughter dome, presence of hypoplastic or aplastic A1 arteries and hypoplastic or fetal PCoA, perpendicular height, width, neck diameter, aspect and size ratio, height/width ratio, and diameters and angles of surrounding parent and daughter vessels. Univariable and multivariable statistical analyses were performed to determine the association of morphological parameters with rupture of PCoA aneurysms. Additional analyses were performed to determine the association of patient factors with the morphological parameters. Irregular, multilobed PCoA aneurysms with larger height/width ratios and larger flow angles were associated with ruptured PCoA aneurysms, whereas perpendicular height was inversely associated with rupture in a multivariable model. Older age was associated with lower aspect ratio, with a trend towards lower height/width ratio and smaller flow angle, features that are associated with a lower rupture risk. Morphological parameters are easy to assess and could help in risk stratification in patients with unruptured PCoA aneurysms. PCoA aneurysms diagnosed at older age have morphological features associated with lower risk.

Morphological Variables Associated With Ruptured Middle Cerebral Artery Aneurysms

BACKGROUND

Geometric factors of intracranial aneurysms and surrounding vasculature could affect the risk of aneurysm rupture. However, large-scale assessments of morphological parameters correlated with intracranial aneurysm rupture in a location-specific manner are scarce.

OBJECTIVE

To investigate the morphological characteristics associated with ruptured middle cerebral artery (MCA) aneurysms.

METHODS

Five hundred sixty-one patients with 638 MCA aneurysms diagnosed between 1990 and 2016 who had available computed tomography angiography (CTA) were included in this study. CTAs were evaluated using the Vitrea Advanced Visualization software for 3-dimensional (3D) reconstruction. Morphological parameters examined in each model included aneurysm projection, wall irregularity, presence of a daughter dome, presence of hypoplastic or aplastic A1 arteries and hypoplastic or fetal posterior communicating arteries (PCoA), aneurysm height and width, neck diameter, bottleneck factor, aspect and size ratio, height/width ratio, and diameters and angles of surrounding parent and daughter vessels. Univariable and multivariable statistical analyses were performed to determine the association of morphological characteristics with rupture of MCA aneurysms. Logistic regression was used to build a predictive MCA score.

RESULTS

Greater bottleneck and size ratio, and irregular, multilobed, temporally projecting MCA aneurysms are associated with higher rupture risk, whereas higher M1/M2 ratio, larger width, and the presence of an ipsilateral or bilateral hypoplastic PCoA were inversely associated with rupture. The MCA score had good predictive capacity with area under the receiver operating curve = 0.88.

CONCLUSION

These practical morphological parameters specific to MCA aneurysms are easy to assess when examining 3D reconstructions of unruptured aneurysms and could aid in risk evaluation in these patients.

A Simple Scoring Model for Prediction of Rupture Risk of Anterior Communicating Artery Aneurysms

Background: The rupture risk of anterior communicating artery aneurysms (ACoAAs) has been known to be higher than that of aneurysms at other locations. Thus, the aim of this study is to investigate the clinical and morphological characteristics associated with risk factors for the rupture of ACoAAs.

Methods: In total, 361 consecutive patients with 361 ACoAAs between August 2011 and December 2017 were retrospectively reviewed. Patients and ACoAAs were divided into ruptured and unruptured groups. In addition to clinical characteristics, ACoAA characteristics were evaluated by CT angiography (CTA). A multiple logistic regression analysis was used to identify the independent risk factors associated with ACoAA rupture. The assignment score of these variables depends on the β coefficient. A receiver operating characteristic (ROC) curve analysis was used to calculate the optimal thresholds.

Results: The multiple logistic regression model revealed that A1 dominance [odds ratio (OR) 3.034], an irregular shape (OR 3.358), and an aspect ratio ≥1.19 (AR; OR 3.163) increased the risk of rupture, while cerebral atherosclerosis (OR 0.080), and mean diameters ≥2.48 mm (OR 0.474) were negatively correlated with ACoAA rupture. Incorporating these five factors, the ROC analysis revealed that the threshold value of the multifactors was one, the sensitivity was 88.3%, and the specificity was 66.0%.

Conclusions: The scoring model is a simple method that is based on A1 dominance, irregular shape, aspect ratio, cerebral atherosclerosis, and mean diameters from CTA and is of great value in the prediction of the rupture risk of ACoAAs.

Intracranial Mirror Aneurysm: Epidemiology, Rupture Risk, New Imaging, Controversies, and Treatment Strategies

There are some controversies about the surgical treatment strategy of mirror aneurysms. Whether to choose 1-stage or 2-stage surgery, bilateral or unilateral craniotomy, or surgical or interventional treatment are the main points in dispute. In this review, the different surgery strategies faced by patients are discussed. Different surgical methods are adopted based on the patient's individual state and the location and size of the aneurysm. A new imaging method is introduced using 3D Slicer, which clearly recognizes the relationship among aneurysm, brain tissue, skull, and nerve. The 3D Slicer can help surgeons undertake adequate preoperative preparation. In addition, we also introduce some ruptured factors (e.g., age, gender, hypertension, morphologic, and hemodynamic) concerning mirror aneurysm. Systematic discussion of the controversies and methods in surgical treatment of mirror aneurysms may provide new perspectives in future research for the prevention and treatment of mirror aneurysms.

A retrospective comparison of sac and lobe morphology between ruptured and unruptured intracranial aneurysms

There are few reliable morphologic indices to aid in the determination of an intracranial aneurysm's rupture risk. We sought to characterize morphological characteristics of aneurysm sacs and their lobes that are associated with ruptured status at time of initial evaluation with diagnostic angiography. These factors could be associated with an aneurysm's risk of rupturing. We retrospectively reviewed all aneurysms imaged with digital subtraction angiography (DSA) at a single institution over five years. Patients presenting with aneurysmal subarachnoid hemorrhage (aSAH) were assigned to the ruptured group, and those presenting without aSAH were assigned to the unruptured group. Angiograms were evaluated for the presence of various morphological parameters. Binary logistic regression was used to assess their associations between groups. A total of 331 aneurysms among 241 patients were included in the analysis. Posterior circulation, larger size ratio, and the presence of two or more lobes were associated with aneurysm rupture (p < 0.001 for each). Aneurysms containing a lobe with a greater height than width were observed more frequently in the ruptured group (OR 5.26, 95% CI 2.66-10.41). In the receiver operating characteristic (ROC) curves, mean diameter had an AUC of 0.72 and an optimum threshold of 2.85 mm. For size ratio, the AUC was 0.70 and the optimum threshold was 2.02. A larger SR was observed in ruptured aneurysms. The presence of multiple lobes and greater lobe height than width were associated with rupture status as well. These factors merit investigation in a prospective study.

Vessel Wall Enhancement in Unruptured Intracranial Aneurysms: An Indicator for Higher Risk of Rupture? High-Resolution MR Imaging and Correlated Histologic Findings

BACKGROUND AND PURPOSE

Recent studies have suggested that wall enhancement of unruptured intracranial aneurysms in high-resolution MR imaging might serve as an imaging biomarker for higher risk of rupture. Histologic studies have revealed a possible association among inflammatory processes, degeneration, and destabilization of the aneurysm wall preceding rupture. Understanding the histologic condition underlying aneurysm wall enhancement could be an important step toward assessing the value of this method for risk stratification. We present our observations of aneurysm wall enhancement in MR vessel wall imaging and underlying histologic changes.

MATERIALS AND METHODS

We reviewed records of patients with an unruptured middle cerebral artery aneurysm who underwent MR vessel wall imaging before aneurysm clipping. Contrast enhancement of the aneurysm wall was dichotomized into either none/faint or strong. Histologic analysis included myeloperoxidase stain for detection of inflammatory cell invasion and CD34 stain for assessment of neovascularization and vasa vasorum.

RESULTS

Thirteen aneurysms were included. Five aneurysms showed strong wall enhancement. Among these, myeloperoxidase staining revealed inflammatory cell infiltration in 4. Three showed neovascularization. In 2 aneurysms, vasa vasorum were present. Seven aneurysms did not show wall enhancement; 1 had only mild enhancement. None of these bore evidence of inflammatory cell invasion or neovascularization, and they all lacked vasa vasorum.

CONCLUSIONS

Wall enhancement in MR vessel wall imaging is associated with inflammatory cell invasion, neovascularization, and the presence of vasa vasorum. Enhancement does not occur when histologic signs of inflammation are absent. Our results support the hypothesis that MR vessel wall imaging could provide valuable information for risk stratification.

Comparison of postsurgical clinical sequences between completely embolized and incompletely embolized patients with wide nicked intracranial aneurysms treated with stent assisted coil embolization technique: A STROBE-compliant study

The technique of stent-assisted coil embolization has been widely used in the clinic, while its efficacy and safety have yet to be evaluated. This study investigates the values of computed tomography angiography (CTA), magnetic resonance angiography (MRA), and digital subtraction angiography (DSA) in evaluating the Enterprise stent-assisted coil embolization in the treatment of intracranial wide-necked aneurysm.A total of 578 intracranial wide-necked aneurysm patients confirmed by MRA + CTA + DSA examinations were included and treated with Enterprise stent-assisted coil embolization in this study. All patients were assigned into complete embolization (CE) group and incomplete embolization (IE) group according to the results of postoperative MRA + CTA + DSA examinations and Raymond grades. Hunt-Hess grades, incidence of complication and Glasgow Outcome Scale (GOS) grades of patients were investigated to assess the therapeutic effect of Enterprise stent-assisted coil embolization in intracranial wide-necked treatment. Multivariate logistic regression analysis was performed to assess risk factors for the therapeutic effect of Enterprise stent-assisted coil embolization in intracranial wide-necked aneurysm.CTA images offered a better and clearer view than MRA and DSA images in both the CE and IE groups. Both the sensitivity and specificity of CTA were apparently higher than those of MRA. Patients in the CE group enjoyed a higher good GOS rate but a lower incidence of complication than those in the IE group. In Enterprise stent-assisted coil embolization treatment, the Hunt-Hess grade, hypertension, and size of artery aneurysm were independent factors affecting the therapeutic effect of Enterprise stent-assisted coil embolization in intracranial wide-necked aneurysm.Compared with MRA, CTA shows a higher value in evaluating the therapeutic effect of Enterprise stent-assisted coil embolization for the treatment of intracranial wide-necked aneurysm, and can thus serve as an important means of predicting the therapeutic effect of endovascular intervention in treating patients with intracranial wide-necked aneurysm.

Number of Cigarettes Smoked Per Day, Smoking Index, and Intracranial Aneurysm Rupture: A Case-Control Study

Background and purpose

We aimed to investigate the effect of smoking on the risk of intracranial aneurysm (IA) rupture (IAR), specifically relationship between the number of cigarettes smoked per day (CPD) or smoking index and the risk of IAR.

Methods

We performed a single-center case-control study of consecutive patients evaluated or treated for IA at our institution from June 2015 to July 2016. Cases were patients with a ruptured IA. Two age- and sex-matched controls with an unruptured IA were included per case. Conditional logistic regression models were used to assess the relationship between both the CPD and smoking index (CPD × years of smoking) and IAR.

Results

The study population included 127 cases of IAR and 254 controls. The higher IAR risk was associated with cigarette smoking (both current and former) (OR, 2.3; 95% CI, 1.1-4.8; P = 0.029). Our subgroup analysis of smokers revealed a significant association between IAR risk and current smoking (OR, 2.8; 95% CI, 1.2-6.3; P = 0.012), current heavy smoking (CPD ≥ 20) (OR, 3.9; 95% CI, 1.4-11.0; P = 0.007), and a smoking index ≥800 (OR, 11.4; 95% CI, 2.3-24.5; P = 0.003). Former smoking was not significantly associated with IAR (OR, 1.1; 95% CI, 0.3-4.0; P = 0.929).

Conclusion

A dose-response relationship has been noted for intensity and duration of smoking consumption and increased risk of IAR. As smoking is modifiable, this finding is important to managing patients with IAs to quit or reduce smoking prior to life-threatening subarachnoid hemorrhage.

Morphological characteristics associated with the rupture risk of mirror posterior communicating artery aneurysms

Objective

Patient related clinical factors and intracranial aneurysms (IAs) at different locations may lead to statistical bias when investigating the rupture risk of IAs. Thus the purpose of this study was to identify the morphological parameters that are related to the rupture of mirror posterior communicating artery aneurysms (PComAAs).

Methods

Between August 2011 and July 2017, 68 patients with mirror PComAAs and aneurysmal subarachnoid hemorrhage were diagnosed by CT angiography at three medical centers. Morphological characteristics for PComAAs included bifurcation, shape, neck width, width, depth, maximum size, flow angle, parent vessel diameter, aspect ratio (AR), depth/width ratio, bottleneck factor, and size ratio (SR). Multiple logistic regression analysis was performed to determine the independent risk factors for rupture. Receiver operating characteristic curve analysis was performed to obtain the optimal thresholds.

Results

AR (OR 5.623) and SR (OR 5.570) were more commonly observed in the ruptured cohort. The threshold values of AR and SR were 0.98 and 1.21, respectively.

Conclusions

Mirror PComAAs are a useful model to investigate the rupture risk of PComAAs. AR (≥0.98) and SR (≥1.21) are better predictors of ruptured PComAAs.

The Siesta Habit is Associated with a Decreased Risk of Rupture of Intracranial Aneurysms

BACKGROUND

Previous studies have examined an association between the siesta habit and hypertension, as well as coronary heart disease. However, the relationship between a siesta and the risk of rupture of an intracranial aneurysm (IA) has not yet been established. We aimed to investigate the effects of a siesta on the risk of rupture of IAs.

METHODS

We prospectively enrolled consecutive patients diagnosed with IAs at our hospital between January 2016 and December 2016. Univariate and multivariate logistic regression analysis were performed to identify independent risk factors associated with IA rupture.

RESULTS

We studied 581 consecutive patients with 514 unruptured and 120 ruptured aneurysms. Univariate analysis demonstrated that hypertension, hyperlipidemia, diabetes mellitus, cigarette smoking, location, size, as well as shape and aspect ratio were associated with the risk of rupture of IAs. Multivariate analysis identified hypertension [odds ratio (OR) 1.68, 95% confidence interval (CI) 1.03-2.73], hyperlipidemia (OR 0.25, 95% CI 0.08-0.72), current cigarette smoking ≥20 cigarettes/day (d) (OR 3.48, 95% CI 1.63-7.47), siesta (siesta time <1 h, OR 0.49, 95% CI 0.24-0.98 and siesta time ≥1 h, OR 0.32, 95% CI 0.19-0.57), location of largest aneurysm on the anterior communicating and internal carotid-posterior communicating artery (PCOM) (anterior communicating artery OR 16.27, 95% CI 7.40-35.79 and PCOM OR 11.21, 95% CI 5.15-24.43), and size of aneurysm ≥7 mm (OR 2.19, 95% CI 1.21-3.97) as independent strong risk factors associated with risk of aneurysm rupture.

CONCLUSION

In the present study, we found that a habitual siesta is a new predictive factor to assess the risk of rupture of an IA. We found the siesta habit may reduce the risk of aneurysm rupture. We also found that hypertension, hyperlipidemia, cigarette smoking, location, and size of aneurysm were associated with the risk of rupture of IAs.

A survey of intracranial aneurysm treatment practices among United States physicians

Background

Recent surveys have failed to examine cerebrovascular aneurysm treatment practices among US physicians.

Objective

To survey physicians who are actively involved in the care of patients with cerebrovascular aneurysms to determine current aneurysm treatment preferences.

Methods

A 25-question SurveyMonkey online survey was designed and distributed electronically to members of the Society of NeuroInterventional Surgery, Society of Vascular and Interventional Neurology, and the American Association of Neurological Surgeons/Congress of Neurological Surgeons Combined Cerebrovascular Section.

Results

211 physicians completed the survey. Most respondents recommend endovascular treatment as the first-line management strategy for most ruptured (78%) and unruptured (71%) aneurysms. Thirty-eight per cent of respondents indicate that they routinely treat all patients with subarachnoid hemorrhage regardless of grade. Most physicians use the International Study of Unruptured Intracranial Aneurysms data for counseling patients on natural history risk (80%); a small minority (11%) always or usually recommend treatment of anterior circulation aneurysms of <5 mm. Two-thirds of respondents continue to recommend clipping for most middle cerebral artery aneurysms, while most (51%) recommend flow diversion for wide-necked internal carotid artery aneurysms. Follow-up imaging schedules are highly variable. Neurosurgeons at academic institutions and those practicing longer were more likely to recommend clipping surgery for aneurysms (p<0.05).

Conclusions

This survey demonstrates considerable variability in patient selection for intracranial aneurysm treatment, preferred treatment strategies, and follow-up imaging schedules among US physicians.

Translucent Appearance of Middle Cerebral Artery Bifurcation Aneurysms Is Risk Factor for Intraoperative Aneurysm Rupture During Clipping

INTRODUCTION

The rupture rate of unruptured intracranial aneurysms is influenced by certain angioarchitectural and hemodynamic characteristics. Recently the translucent appearance of aneurysms was described as a possible risk factor for aneurysm rupture. In this study, we investigate the intraoperative rupture risk of surgically clipped unruptured translucent aneurysms (TAs).

METHOD

Clinical and radiologic data of microsurgically treated unruptured middle cerebral artery (MCA) bifurcation aneurysms between 2013 and 2015 were collected and analyzed. Aneurysms were divided into TA as defined as >90% reddish pigmentation appearance of the aneurysm wall or non-TA (NTA) according to the observation under microscope by a single neurosurgeon. Parameters were analyzed using univariate and multivariate statistical analyses.

RESULT

A total of 41 unruptured MCA bifurcation aneurysms were included in the analysis, and 68.2% (28/41) were defined as TA. The univariate analysis showed that aneurysm characteristics (Dmax, Wmax, height, and lower size ratio [SR]) that were small in nature were associated with TAs. TAs were associated with intraoperative rupture (28.6% vs. 0%, P = 0.04). Multivariate logistic regression analysis found that the lower SR is the independent risk factor for TAs.

CONCLUSION

The results demonstrate that a lower SR correlates with TA in the MCA bifurcation and the thinner wall of the TA causes intraoperative rupture more likely. These results provide important information on the fragility of TAs and might influence the treatment decisions in unruptured MCA bifurcation aneurysms with lower SRs.

Risk Factors for the Rupture of Middle Cerebral Artery Bifurcation Aneurysms Using CT Angiography

BACKGROUND AND PURPOSE

To investigate the clinical and morphological characteristics associated with risk factors for the rupture of bifurcation-type middle cerebral artery aneurysms (MCAAs).

METHODS

A total of 169 consecutive patients with 177 bifurcation-type MCAAs were reviewed from August 2011 to January 2016. Based on the clinical and morphologic characteristics findings, the risk factors of aneurysm rupture were assessed using statistical methods.

RESULTS

Age, cerebral atherosclerosis, no hypertension, hypertension grade 2 and coronary artery disease (CAD) were negatively correlated with aneurysm rupture. The mean diameter (MD) of the parent and two daughter arteries was negatively correlated with rupture. Aneurysms with irregularity, depth, width, maximum size, aspect ratio, depth-to-width ratio, bottleneck factor, and size ratio were positively correlated with rupture. The multivariate logistic regression model revealed that irregular shape (odds ratio (OR) 2.697) and aspect ratio (OR 3.723) were significantly and positively correlated with rupture, while cerebral atherosclerosis (OR 0.033), CAD (OR 0.080), and MD (OR 0.201) were negatively correlated with rupture. Receiver operating characteristic analysis revealed that the threshold value of the aspect ratio and MD were 0.96 and 2.43 mm, respectively.

CONCLUSIONS

Cerebral atherosclerosis and CAD are protective factors against rupture. Morphological characteristics such as an aneurysm with an irregular shape, a high aspect ratio (>0.96) and a small MD (<2.43 mm) are likely better predictors of rupture.

Simultaneous or Early Sequential Rupture of Multiple Intracranial Aneurysms: A Rare and Insufficiently Understood Entity

BACKGROUND

Simultaneous or early sequential rupture of multiple intracranial aneurysms (MIAs) is encountered rarely, with no more than 10 cases having been reported. As a result of its rarity, there are a lot of questions concerning this entity need to be answered.

CASE DESCRIPTION

A 67-year-old woman was admitted to the First Hospital of Jilin University (Eastern Division) from a local hospital after a sudden onset of severe headache, nausea, and vomiting. Head computed tomography (CT) at the local hospital revealed diffuse subarachnoid hemorrhage (SAH) that was concentrated predominately in the suprasellar cistern and interhemispheric fissure. During her transfer to our hospital, she experienced another episode of sudden headache. CT on admission to our hospital revealed that the SAH was increased with 2 isolated hematomas both in the interhemispheric fissure and the left paramedian frontal lobe. Further CT angiography and intraoperative findings were in favor of early sequential rupture of 2 intracranial aneurysms. To further elucidate the characteristics, mechanism, management, and prognosis of this specific entity, we conducted a comprehensive review of the literature.

CONCLUSIONS

The mechanism of simultaneous or early sequential rupture of MIAs is still obscure. Transient elevation of blood pressure might play a role in the process, and preventing the sudden elevation of blood pressure might be beneficial for patients with aneurysmal SAH and MIAs. The management of simultaneously or early sequentially ruptured aneurysms is more complex for its difficulty in responsible aneurysm determination, urgency in treatment, toughness in intraoperative manipulation and poorness in prognosis.