The impact of size and location on rupture of intracranial aneurysms

Modeling and evaluation of biomechanics and hemodynamic based on patient-specific small intracranial aneurysm using fluid-structure interaction

BACKGROUND AND OBJECTIVE

Rupture of small intracranial aneurysm (IA) often leads to the development of highly fatal clinical syndromes such as subarachnoid hemorrhage. Due to the patient specificity of small IA, there are many difficulties in evaluating the rupture risk of small IA such as multiple influencing factors, high clinical experience requirements and poor reusability.

METHODS

In this study, clinical methods such as transcranial doppler (TCD) and magnetic resonance imaging (MRI) are used to obtain patient-specific parameters, and the fluid-structure interaction method (FSI) is used to model and evaluate the biomechanics and hemodynamics of patient-specific small IA.

RESULTS

The results show that a spiral vortex stably exists in the patient-specific small IA. Due to the small size of the patient-specific small IA, the blood flow velocity still maintains a high value with maximum reaching 3 m/s. The inertial impact of blood flow and vortex convection have certain influence on hemodynamic and biomechanics parameters. They cause three high value areas of WSSM on the patient-specific small IA with maximum of 180 Pa, 130 Pa and 110 Pa, respectively. They also cause two types of WSS concentration points, positive normal stress peak value areas and negative normal stress peak value areas to appear.

CONCLUSION

This paper found that the factors affecting hemodynamic parameters and biomechanical parameters are different. Unlike hemodynamic parameters, biomechanical parameters are also affected by blood pressure in addition to blood flow velocity. This study reveals the relationship between the flow field distribution and changes of patient-specific small IA, biomechanics and hemodynamics.

Toward Grading Subarachnoid Hemorrhage Risk Prediction: A Machine Learning-Based Aneurysm Rupture Score

OBJECTIVE

Existing approaches neither provide an accurate prediction of subarachnoid hemorrhage (SAH) nor offer a quantitative comparison among a group of its risk factors. To evaluate the population, hypertension, age, size, earlier subarachnoid hemorrhage, and location (PHASES) and unruptured intracranial aneurysm treatment score (UIATS) scores and develop an Artificial Intelligence-based 5-year and lifetime aneurysmal rupture criticality prediction (ARCP) score for a set of risk factors.

METHODS

We design various location-specific and ensemble learning models to develop lifetime rupture risk, employ the longitudinal data to develop a linear regression-based model to predict an aneurysm's growth score, and use the Apriori algorithm to identify risk factors strongly associated with SAH. We develop ARCP by integrating output of Apriori algorithm and ML models and compare with PHASES and UIATS scores along with the scores of a multidisciplinary team of neurosurgeons.

RESULTS

The PHASES and UIATS scores show sensitivities of 22% and 35% and specificities of 76% and 79%, respectively. Location-specific models show precision and recall of 93% and 90% for the middle cerebral artery, 83% and 80% for the anterior communicating artery, and 80% and 80% for the supraclinoid internal carotid artery, respectively. The ensemble method shows both precision and recall of 80%. The validation of the models shows that ARCP performs better than our control group of neurosurgeons. Data-driven knowledge produces comparisons among 61 risk factor combinations, 11 ranked minor, 8 moderate, and 41 severe, and 1 of which is a critical factor.

CONCLUSIONS

The PHASES and UIATS are weak predictors, and the ARCP score can identify, and grade, risk factors associated with SAH.

What Are the Predictors of Intracranial Aneurysm Rupture in Indonesian Population Based on Angiographic Findings? Insight from Intracranial Aneurysm Registry on Three Comprehensive Stroke Centres in Indonesia

Objectives

What are the Predictors of Intracranial Aneurysm (IA) Rupture based on angiographic findings among patients in Indonesia's Population Based on Angiographic Findings.

Materials and Methods

We conducted a cross-sectional study on subjects with IA not caused by congenital aetiologies or other vascular malformations with cerebral angiography performed from January 2017 to January 2021. Demographic data and aneurysm profile, which include aneurysm count, size, location, and rupture event, were collected. The correlation between risk factors and IA rupture events was determined using bivariate and multivariate analysis.

Results

From 100 angiography data (33 males and 67 females), the mean subject age is 51.94 ± 10.78. We observe a total of 121 IAs from all subjects. Most of the IAs are in the anterior circulation (104 aneurysms, 85.96%), have small size (77 aneurysms, 63.64%), and are found in ruptured conditions (90 aneurysms, 74.38%). Males have a greater aneurysm count (1.36 ± 0.74 vs. 1.13 ± 0.55, p = 0.036) and larger aneurysm size (p = 0.002). Aneurysm size is significantly correlated with its location (p = 0.008). Medium size (p = 0.019; OR 2.62, 95% CI 1.08-6.36) and location other than the internal carotid artery are associated with increased rupture event. Multivariate analysis revealed that gender (p = 0.031; aOR 5.37, 95% CI 1.17-24.70) is a significant risk factor of IA rupture event.

Conclusion

IA profiling will enable clinicians to determine the risk of rupture and treatment plans for the Indonesian population. Further studies with a larger sample size are required to confirm these findings.

Clinicoradiological Profile and Outcome of Microsurgical Clipping of Ruptured Anterior Circulation Aneurysms: A Single-Institute Experience

Introduction:

Prevalence of intracranial aneurysms is estimated to be from 1% to 5% of population, most of them are small and located in the anterior circulation. The real danger is when an aneurysm ruptures, leading to a subarachnoid hemorrhage (SAH). SAH is a catastrophic event with a mortality rate of 25% to 50%. Permanent disability occurs in nearly 50% of the survivors. Fifteen percent of patients expire before reaching the hospital and 25% die within 24 h. The purpose of our study is to report the clinicoradiological data and outcome of microsurgical clipping of ruptured anterior circulation aneurysms in our center.

Materials and Methods:

This study included ruptured anterior circulation aneurysms admitted to tertiary care hospital in northern India from January 2018 to June 2020. The final outcome of patients was analyzed with Glasgow Outcome Score (GOS) at the time of discharge from the hospital.

Results:

A total of 53 patients with ruptured anterior circulation aneurysm underwent microsurgical clipping comprising 25 (47.2%) males and 28 (52.8%) females. The mean neck size of all aneurysms was 3.43 ± 1.66 mm. The mean hospital stay was longer in patients having preoperative intraventricular hemorrhage (IVH) (35.96 ± 27.27 days) and postoperative complications (43.36 ± 29.76 days) compared to patients who did not have IVH (21.10 ± 15.47 days) and postoperative complications (18 ± 6.54 days). P value was ≤0.05. Patients with preoperative hydrocephalus had GOS 3.44 ± 1.20 at discharge compared to nonhydrocephalus who had GOS 4.32 ± 1.07 (P = 0.009). Patients with Intracerebral Hemorrhage (ICH) and non-ICH had GOS 3.31 ± 1.38 and 4.28 ± 1.01, respectively (P = 0.009).

Conclusion:

Poor outcome at the time of discharge after the surgical treatment of anterior circulation aneurysms was associated with poor world federation of neurological surgeons grade on admission, presence of IVH, hydrocephalus, intracerebral hemorrhage, and postoperative cerebral infarcts.

Introducing the Rupture Criticality Index to Compare Risk Factor Combinations Associated With Aneurysmal Rupture

BACKGROUND

Relative risk is insufficient to guide treatment decision-making for unruptured intracranial aneurysms. Our objective was to introduce a novel risk assessment methodology called the Rupture Criticality Index (RCI), which allows for concurrent evaluation of groups of risk factors (RFs).

METHODS

From a retrospective database of saccular aneurysms, we identify 915 patients and delineate 50 potential RFs for aneurysms in 11 unique locations. RF combinations for multivariable analysis were defined by aneurysm size, location, and a third variable from the study design. Data analysis was performed by applying frequency distribution methods to define the RCI of each RF combination.

RESULTS

RF combinations at greatest risk were small (4.8-8.2 mm) or medium (8.3-14.5 mm) anterior communicating aneurysms (ACoA) in male individuals (RCI 9.87-10), small ACoA in those ≤37 years or 38-55 years (RCI 8.67-8.99), medium basilar tip aneurysms (BTAs) in male individuals (RCI 10), and large (14.6-22.5 mm) BTA in Caucasians or those aged 38-55 years (RCI 9.25, 9.35, respectively).

CONCLUSIONS

We introduce the concept of RCI and compare how RF combinations are associated with aneurysmal rupture. This novel approach to aneurysmal rupture identifies high-risk clinical presentations and can be used to guide clinical decision-making in patients with non-traditional risks.

Impact of Ruptured Aneurysm Circulation on Mortality: A Nationwide Inpatient Sample Analysis

OBJECTIVE

This study investigates the effect of aneurysm circulation on mortality and patient outcomes after aneurysmal subarachnoid hemorrhage (SAH) within the United States.

METHODS

A retrospective cohort study was conducted using the Nationwide Inpatient Sample (NIS), a part of the Healthcare Cost and Utilization Project (HCUP), with ICD-10 codes for non-traumatic SAH between 2015-2016. Aneurysms were stratified as either anterior or posterior circulation. Multivariate logistic regression was used to find the impact of selected variables on the odds of mortality.

RESULTS

The NIS reported 1,892 cases of non-traumatic SAH within the study period that were predominantly anterior circulation (82.6%), female (68.6%), white (57.7%), with mean age of 59.07 years, and in-hospital mortality of 21.4%. Anterior circulation aneurysms were associated with lower severity of initial illness (p = 0.014) but higher likelihood of vasospasm (p = 0.0006) than those of the posterior circulation. In a multivariate logistic regression analysis, mortality was associated with posterior circulation aneurysms (OR: 1.42; CI 95% 1.005-20.10, p = 0.047), increasing age (OR: 1.035; 95% CI 1.022-1.049; p < 0.0001), and shorter hospital stays (OR: 0.7838; 95% CI 0.758-0.811; p < 0.0001). Smoking history (OR: 0.825; 95% CI 0.573-1.187, p > 0.05) and vasospasm (OR: 1.005; 95% CI 0.648-1.558; p > 0.05) were not significantly associated with higher odds of mortality.

CONCLUSIONS

Mortality following aneurysmal SAH is associated with posterior circulation aneurysms, and increasing age, but not smoking history or vasospasm. These findings may be useful for prognostication and counseling patients and families.

The aetiologies of the unilateral oculomotor nerve palsy: a review of the literature

Oculomotor nerve palsy (ONP) is an important and common clinical diagnosis. Its main features are diplopia and ptosis. Its aetiologies are various and complex. A number of different conditions have been reported to cause ONP, such as diabetes mellitus, aneurysm, tumours, painful ophthalmoplegia, pituitary lesions, cavernous sinus lesions, central nervous system infections, and subarachnoid haemorrhage. A patients needs to undergo several tests in order to establish the correct underlying pathology. In this review, we have summarized the aetiologies of the unilateral ONP, and discussed their relative clinical features, pathogenesis, diagnostic criteria, treatment options, and prognosis. We searched PubMed for papers related to ONP and its aetiologies, and selected the publications, which seemed appropriate.

Carotid Artery Aneurysm: A Rare Cause of Hemotympanum

Temporal bone fractures can occur as a result of various head trauma. The most common cause of the hemotympanum is traumatic temporal bone fracture. Facial paralysis and hearing loss can be seen associated with temporal bone fracture. The development of the internal carotid artery aneurysm after temporal bone fracture is extremely rare. In this article, the authors evaluated carotid artery aneurysm that developed after temporal fracture and aneurism compressed by coagulated blood mass which showed itself as a hemotympanum. The internal carotid artery aneurysm that induced by temporal bone fracture and presented as hemotympanum has not been reported yet. This patient is the first case in the literature. Diagnosis, treatment, and follow-up options will be discussed in the light of current literature.

Size and location correlations with higher rupture risk of intracranial aneurysms

AIM

The purpose of this study was to investigate the impact of size and location of the intracranial aneurysm on rupture probability.

MATERIAL AND METHODS

265 patients with diagnosis of intracranial aneurysms were admitted to the department from January 2012 to December 2013. The characteristic of aneurysm, such as median size, location, single and multiple aneurysms and presentation were retrospectively reviewed using cerebral angiography reports.

RESULTS

There were 265 patients admitted with the diagnosis of intracranial aneurysms, 193 with single and 72 with multiple aneurysms. Among them there were 197 women (74,3%) and 68 men (25,7%). The total number of aneurysms harbored by the patients with multiple aneurysms were 184. Among all patients 96 had ruptured aneurysm, most of them located at the AComA and the minority of ruptured aneurysms were located at the ICA and MCA, In most cases the size of ruptured aneurysm was smaller than 10 mm.

CONCLUSION

The location of an aneurysm is an important factor allowing to predict the rupture probability and to plan proper treatment. The size of the aneurysm is also very useful predictor especially correlated with the location but the impact on rupture probability still needs further examination.

Unruptured intracranial aneurysms: An updated review of current concepts for risk factors, detection and management

The management of patients with unruptured intracranial aneurysms (UIAs) is a complex clinical challenge and constitutes an immense field of research. While a preponderant proportion of these aneurysms never rupture, the consequences of such an event are severe and represent an important healthcare problem. To date, however, the natural history of UIAs is not completely understood and there is no accurate means to discriminate the UIAs that will rupture from those that will not. Yet, a good understanding of the recent evidence and future perspectives is needed when advising a patient with IA to tailor any information to the given patient's level of risk and psychoaffective status. Thus, this review addresses the current concepts of epidemiology, risk factors, detection and management of UIAs.

Imaging of Oculomotor (Third) Cranial Nerve Palsy

When evaluating a patient with an oculomotor cranial nerve palsy it may be unclear which neuroimaging modality is optimal; MRI, MR angiography, computed tomography, computed tomography angiography, or intraarterial digital subtraction angiography. We discuss the clinical guidelines in the evaluation of such patients and review neuroimaging techniques, outlining the advantages and disadvantages of each.

Digital subtraction angiography findings and population demographics of patients with subarachnoidal haemorrhage and subsequent causative aneurysms at Universitas Academic Hospital, Bloemfontein

Background: Subarachnoid haemorrhage (SAH) secondary to aneurysmal rupture may be associated with serious neurological sequelae or even mortality. According to international literature, only aneurysms >7 mm or aneurysms in the posterior circulation require treatment. Retrospective single-centre studies have, however, disputed this after demonstrating that the average size of ruptured aneurysms are <7 mm. More recent guidelines place less emphasis on size and more on associated risk factors.Objectives: The aim of this investigation was to assess the aneurysm characteristics and demographics of patients who presented to our institution with SAH secondary to an aneurysm detected at digital subtraction angiography (DSA).Method: A retrospective descriptive study was conducted. Patients who presented with SAH over a 6-year period, from 2008 to 2013, were included. The average size of the intracranial aneurysms at the time of rupture was analysed. Data about aneurysm characteristics and patient demographics were obtained from patient files. Data were analysed by the researchers with assistance from the Department of Biostatistics.Results: In total, 161 of 374 patients who underwent DSA had ruptured aneurysms. Most patients were women with ages ranging from 18 to 73 years (mean 45 years). The mean size of aneurysms were 5.8 mm (range 1.2 mm – 20 mm), with 74.5% of aneurysms <7 mm. Most aneurysms were noted involving the anterior circulation (72%), with the majority arising from the anterior communicating artery (36.7%).Conclusion: We found that aneurysms rupture at sizes <7 mm and are commonly located in the anterior circulation. Our findings emphasise the importance of conducting institutional reviews to consider adapting international treatment guidelines for the local South African situation.

Particularly interesting Cys-His-rich protein is highly expressed in human intracranial aneurysms and resists aneurysmal rupture

Particularly interesting Cys-His-rich protein (PINCH) has several biological functions in cancer development, invasion and metastasis in malignant cells, and the expression of PINCH is upregulated in several cancer types, including breast cancer, gastric adenocarcinoma and rectal cancer. However, the contribution of PINCH to human cerebral aneurysms remains largely unknown. Therefore, the significance of PINCH expression in cerebral aneurysm growth and rupture was examined in the present study. The protein expression levels of alpha-smooth muscle actin, osteopontin (OPN), matrix metalloproteinase (MMP) 9 and PINCH were evaluated using immunohistochemistry and western blot analyses. The results demonstrate that the protein expression levels of OPN, MMP9 and PINCH in the unruptured intracranial aneurysm (UA) and ruptured intracranial aneurysm (RA) groups were markedly higher than those of the control group, whereas OPN and PINCH expression levels were decreased in the RA group compared to those of the UA group. In addition, there was a strong correlation between PINCH and tumor size (r=0.650 and P=0.0026), as well as between PINCH and OPN (r=0.639 and P=0.0033) in the unruptured cerebral aneurysms. However, the correlation between PINCH and tumor size (r=0.450 and P=0.1393) and between PINCH and OPN (r=0.366 and P=0.2426) revealed no obvious difference in the ruptured cerebral aneurysms. In conclusion, PINCH was highly expressed in the UAs, which may be a critical factor for preventing aneurysmal rupture. Moreover, PINCH may facilitate intracranial aneurysm progression, at least partially, through the activation of extracellular signal-regulated kinase signaling and the suppression of c-Jun N-terminal kinase signaling.

Size and Location of Ruptured Intracranial Aneurysms: A 5-Year Clinical Survey

BACKGROUND

Prospective international cohort trials have suggested that incidental cerebral aneurysms with diameters less than 10 mm are unlikely to rupture. Consequently, small ruptured cerebral aneurysms should rarely be seen in clinical practice. To verify this theory, dimensions and locations of ruptured cerebral aneurysms were analyzed across the state of Tasmania, Australia.

METHODS

We retrospectively reviewed medical records and diagnostic tests of all patients admitted with ruptured cerebral aneurysms during a 5-year interval. Aneurysm location, maximum size, dome-to-neck ratio, volume, and presence of daughter sacs were determined by preoperative digital subtraction angiography or computed tomography angiography.

RESULTS

A total of 131 ruptured cerebral aneurysms were encountered and treated by microsurgical clipping (n = 59) or endovascular techniques (n = 72). The mean maximum aneurysm diameter was 6.4 ± 3.7 mm, dome-to-neck ratio 2 ± 0.8, aneurysm volume 156 ± 372 mm(3), and daughter sacs were present in 70 aneurysms (53.4%). The anterior communicating artery was the most common location (37.4%). Cumulative maximum diameters of ruptured aneurysms were ≤5 mm in 49%, ≤7 mm in 73%, and ≤10 mm in 90%.

CONCLUSIONS

Despite findings from prospective international cohort trials, small ruptured intracranial aneurysms are common in clinical practice. In consequence, it seems important to identify those patients with small but vulnerable unruptured aneurysms before conservative management is considered.