The detection and management of unruptured intracranial aneurysms

Single Component Polymers, Polymer Blends, and Polymer Composites for Interventional Endovascular Embolization of Intracranial Aneurysms

Intracranial aneurysm is the abnormal focal dilation in brain arteries. When untreated, it can enlarge to rupture points and account for subarachnoid hemorrhage cases. Intracranial aneurysms can be treated by blocking the flow of blood to the aneurysm sac with clipping of the aneurysm neck or endovascular embolization with embolics to promote the formation of the thrombus. Coils or an embolic device are inserted endovascularly into the aneurysm via a micro-catheter to fill the aneurysm. Many embolization materials have been developed. An embolization coil made of soft and thin platinum wire called the "Guglielmi detachable coil" (GDC) enables safer treatment for brain aneurysms. However, patients may experience aneurysm recurrence because of incomplete coil filling or compaction over time. Unsatisfactory recanalization rates and incomplete occlusion are the drawbacks of endovascular embolization. So, the fabrication of new medical devices with less invasive surgical techniques is mandatory to enhance the long-term therapeutic performance of existing endovascular procedures. For this aim, the current article reviews polymeric materials including blends and composites employed for embolization of intracranial aneurysms. Polymeric materials used in embolic agents, their advantages and challenges, results of the strategies used to overcome treatment, and results of clinical experiences are summarized and discussed.

Exosomes in Vascular/Neurological Disorders and the Road Ahead

Neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), stroke, and aneurysms, are characterized by the abnormal accumulation and aggregation of disease-causing proteins in the brain and spinal cord. Recent research suggests that proteins linked to these conditions can be secreted and transferred among cells using exosomes. The transmission of abnormal protein buildup and the gradual degeneration in the brains of impacted individuals might be supported by these exosomes. Furthermore, it has been reported that neuroprotective functions can also be attributed to exosomes in neurodegenerative diseases. The potential neuroprotective functions may play a role in preventing the formation of aggregates and abnormal accumulation of proteins associated with the disease. The present review summarizes the roles of exosomes in neurodegenerative diseases as well as elucidating their therapeutic potential in AD, PD, ALS, HD, stroke, and aneurysms. By elucidating these two aspects of exosomes, valuable insights into potential therapeutic targets for treating neurodegenerative diseases may be provided.

Cerebral Aneurysm Characteristics and Surgical Outcomes: An In-Depth Analysis of 346 Cases Operated Using Microsurgical Clipping

This comprehensive study analyzes 346 surgically treated intracranial aneurysms, emphasizing the importance of understanding risk factors and prevalent characteristics in patients. Intracranial aneurysms, primarily of the saccular or berry type, significantly contribute to nontraumatic subarachnoid hemorrhages and demonstrate a rising incidence due to advances in imaging techniques. The study highlights a gender discrepancy in aneurysm occurrence and a higher prevalence in individuals over 30 years old. The research delves into various aspects, including aneurysm localization, diameter, neck dimensions, and rupture status, with a focus on the anterior communicating artery and middle communicating artery as predominant locations. Significant findings include the prevalence of ruptured aneurysms and the impact of arterial hypertension, atherosclerosis, obesity, and diabetes on aneurysm epidemiology. The study also investigates the occurrence of vasospasm, a significant factor in delayed morbidity and mortality in aneurysmal subarachnoid hemorrhage. The utilization of the Glasgow Outcome Scale and other quantification scales aids in understanding the severity and postoperative outcomes of intracranial aneurysms. Challenges such as the incidence of reopenings and postoperative osteomyelitis are addressed, underlining the need for refined protocols and multidisciplinary approaches in treatment. The study's results contribute to the existing knowledge base on intracranial aneurysms, emphasizing the importance of ongoing research and tailored treatment strategies. The comprehensive nature of this analysis, covering preoperative, intraoperative, and postoperative factors, provides valuable insights into the complex interplay of risk factors and clinical outcomes in patients with intracranial aneurysms.

Outcome after Neuro-interventional Treatment of Intracranial Aneurysm (as a First Treatment Modality)

Endovascular treatment is widely applied as the first-line treatment for intracranial aneurysms and includes simple coiling (SC), stent-assisted coiling (SAC), flow diversion stent, and flow disruption stent. The present study is a retrospective cohort study performed in Imam Khomeini Hospital, Department of Neurovascular Intervention, between March 2016 and March 2021. A total number of 229 patients with intracranial aneurysms who underwent therapeutic intravascular interventions were enrolled, of which 89 were treated with SC, 111 with SAC, 25 with flow diversion stent, and 4 with flow disruption stent. The mean age of the subjects was 51.8±12.6 years, and 51.1% were male. Modified Raymond-Roy classification (MRRC) was used to define the occlusion outcome. The success rate, considered as Class I and Class II of MRRC at treatment time was 89% (94.4% in SC, and 84.7% in SAC), which was increased to 90.9% (94% in SC, 93% in SAC, 69.6% in flow diversion stenting, 100% in flow disruption) at 6-month follow-up, and 84.6% (80.8% in SC, 87.8% in SAC, 78.3% in flow diversion stenting, and 100% in flow disruption) at 12-month follow-up. The mean modified Rankin Scale (mRS) before the procedure was 0.05±0.26 which was increased to 0.22±0.76 after the procedure, 0.22±0.76 at 6 months, and 0.30±0.95 at 12 months (P<0.001). Similar to previous studies, the present study demonstrates that neurovascular intervention can treat ruptured aneurysms as the first therapeutic modality with favourable outcomes. A double-blind, randomized clinical trial is needed to eliminate the confounding factors and better demonstrate the outcome.

Vascular Complications in Autosomal Dominant Polycystic Kidney Disease: Perspectives, Paradigms, and Current State of Play

Autosomal dominant polycystic kidney disease (ADPKD) is the leading cause of inherited kidney disease with significant contributions to CKD and end-stage kidney disease. The underlying polycystin proteins (PC1 and PC2) have widespread tissue expression and complex functional roles making ADPKD a systemic disease. Vascular complications, particularly intracranial aneurysms (ICA) are the most feared due to their potential for devastating neurological complications and sudden death. Intracranial aneurysms occur in 8-12% of all patients with ADPKD, but the risk is intensified 4-5-fold in those with a positive family history. The basis for this genetic risk is not well understood and could conceivably be due to features of the germline mutation with a significant contribution of other genetic modifiers and/or environmental factors. Here we review what is known about the natural history and genetics of unruptured ICA in ADPKD including the prevalence and risk factors for aneurysm formation and subarachnoid hemorrhage. We discuss two alternative screening strategies and recommend a practical algorithm that targets those at highest risk for ICA with a positive family history for screening.

Mathematical Analysis of the Effectiveness of Screening for Intracranial Aneurysms in First-Degree Relatives of Persons with Subarachnoid Hemorrhage

OBJECTIVE

Population screening for aneurysms in patients with risk factors and preventive surgical treatment are beneficial according to numerous studies. One of the most significant risk factors is heredity, namely, the presence of first-degree relatives (FDR) with aneurysmal subarachnoid hemorrhage (aSAH). Nevertheless, there are still no generally accepted approaches or evidence bases regarding the benefits of the aneurysm screening strategy.

METHODS

Mathematical modeling of the dynamics of aneurysm development in the population was carried out using an algorithm implementing a discrete Markov's chain. To implement the model, all probabilities of events and distributions are taken from available literature sources. Three-dimensional time of flight noncontrast magnetic resonance angiography was chosen as a screening method. Patients underwent preventive surgical treatment if an aneurysm was detected.

RESULTS

Screening and preventive treatment in the general population reduces the prevalence of aneurysms by 1.74% (3.44% in the FDR group) and the prevalence of aSAH by 14.36% (37.48% in the FDR group). Mortality due to aSAH was reduced by 14.44%. The number of disabilities also decreases. The occurrence of deep disability was reduced by 20.2% in the FDR group. Economic analysis of the part of the population consisting of FDRs showed annual savings of ies also decr CONCLUSIONS: The mathematical model demonstrated that screening and preventive treatment of cerebral aneurysms can reduce aSAH-associated morbidity and mortality. In the FDR group, there was decrease in the prevalence of aSAH and decrease in associated mortality. Screening for cerebral aneurysms is cost-effective.

Efficacy of Acetylcysteine and Selenium in Aneurysmal Subarachnoid Hemorrhage Patients: A Prospective, Multicenter, Single Blind Randomized Controlled Trial

BACKGROUND

Subarachnoid hemorrhage (SAH) patients have oxidative stress results in inflammation, tissue degeneration and neuronal damage. These deleterious effects cause aggravation of the perihematomal edema (PHE), vasospasm, and even hydrocephalus. We hypothesized that antioxidants may have a neuroprotective role in acute aneurysmal SAH (aSAH) patients.

METHODS

We conducted a prospective, multicenter randomized (single blind) trial between January 2017 and October 2019, investigating whether antioxidants (acetylcysteine and selenium) have the potential to improve the neurologic outcome in aSAH patients. The antioxidant patient group received antioxidants of acetylcysteine (2,000 mg/day) and selenium (1,600 µg/day) intravenously (IV) for 14 days. These drugs were administrated within 24 hours of admission. The non-antioxidant patient group received a placebo IV.

RESULTS

In total, 293 patients were enrolled with 103 patients remaining after applying the inclusion and exclusion criteria. No significant differences were observed in the baseline characteristics between the antioxidant (n = 53) and non-antioxidant (n = 50) groups. Among clinical factors, the duration of intensive care unit (ICU) stay was significantly shortened in patients who received antioxidants (11.2, 95% confidence interval [CI], 9.7-14.5 vs. 8.3, 95% CI, 6.2-10.2 days, P = 0.008). However, no beneficial effects were observed on radiological outcomes.

CONCLUSION

In conclusion, antioxidant treatment failed to show the reduction of PHE volume, mid-line shifting, vasospasm and hydrocephalus in acute SAH patients. A significant reduction in ICU stay was observed but need more optimal dosing schedule and precise outcome targets are required to clarify the clinical impacts of antioxidants in these patients.

TRIAL REGISTRATION

Clinical Research Information Service Identifier: KCT0004628.

Reinforcement learning for patient-specific optimal stenting of intracranial aneurysms

Developing new capabilities to predict the risk of intracranial aneurysm rupture and to improve treatment outcomes in the follow-up of endovascular repair is of tremendous medical and societal interest, both to support decision-making and assessment of treatment options by medical doctors, and to improve the life quality and expectancy of patients. This study aims at identifying and characterizing novel flow-deviator stent devices through a high-fidelity computational framework that combines state-of-the-art numerical methods to accurately describe the mechanical exchanges between the blood flow, the aneurysm, and the flow-deviator and deep reinforcement learning algorithms to identify a new stent concepts enabling patient-specific treatment via accurate adjustment of the functional parameters in the implanted state.

Knowledge Mapping of Intracranial Aneurysm Clipping: A Bibliometric and Visualized Study (2001-2021)

BACKGROUND

Intracranial aneurysms (IAs) are common cerebrovascular diseases with high rates of mortality and disability. With the development of endovascular treatment technologies, the treatment of IAs has gradually turned to endovascular methods. However, because of the complex disease characteristics and technical challenges of IA treatment, surgical clipping still plays an important role. However, no summary has been performed of the research status and future trends in IA clipping.

METHODS

Publications related to IA clipping from 2001 to 2021 were retrieved from the Web of Science Core Collection database. We conducted a bibliometric analysis and visualization study with the help of VOSviewer software and R program.

RESULTS

We included 4104 articles from 90 countries. The volume of publications on IA clipping, in general, has increased. The United States, Japan, and China were the countries with the most contributions. The University of California, San Francisco, Mayo Clinic, and the Barrow Neurological Institute are the main research institutions. World Neurosurgery and the Journal of Neurosurgery were the most popular journal and most co-cited journal, respectively. These publications came from 12,506 authors, of whom Lawton, Spetzler, and Hernesniemi had reported the most studies. The reports from the past 21 years on IA clipping can generally be divided into 5 parts: (1) characteristics and technical difficulties of IA clipping; (2) perioperative management and imaging evaluation of IA clipping; (3) risk factors for subarachnoid hemorrhage caused by rupture after IA clipping; (4) outcomes, prognosis, and related clinical trials of IA clipping; and (5) endovascular management for IA clipping. "Occlusion," "experience," "internal carotid artery," "intracranial aneurysms," "management," and "subarachnoid hemorrhage" were the major keywords for future research hotspots.

CONCLUSIONS

The results from our bibliometric study have clarified the global research status of IA clipping between 2001 and 2021. The United States contributed the most publications and citations, and World Neurosurgery and Journal of Neurosurgery can be considered landmark journals in this field. Studies regarding occlusion, experience, management, and subarachnoid hemorrhage will be the research hotspots related to IA clipping in the future.

Malpractice Litigation Related to Diagnosis and Treatment of Intracranial Aneurysms

BACKGROUND AND PURPOSE

Approaches to management of intracranial aneurysms are inconsistent, in part due to apprehension relating to potential malpractice claims. The purpose of this article was to review the causes of action underlying medical malpractice lawsuits related to the diagnosis and management of intracranial aneurysms and to identify the factors associated and their outcomes.

MATERIALS AND METHODS

We consulted 2 large legal databases in the United States to search for cases in which there were jury awards and settlements related to the diagnosis and management of patients with intracranial aneurysms in the United States. Files were screened to include only those cases in which the cause of action involved negligence in the diagnosis and management of a patient with an intracranial aneurysm.

RESULTS

Between 2000 and 2020, two hundred eighty-seven published case summaries were identified, of which 133 were eligible for inclusion in the analysis. Radiologists constituted 16% of 159 physicians sued in these lawsuits. Failure to diagnose was the most common medical malpractice claim referenced (100/133 cases), with the most common subgroups being "failure to include cerebral aneurysm as a differential and thus perform adequate work-up" (30 cases), and "failure to correctly interpret aneurysm evidence on CT or MR imaging" (16 cases). Only 6 of these 16 cases were adjudicated at trial, with 2 decided in favor of the plaintiff (awarded $4,000,000 and $43,000,000, respectively).

CONCLUSIONS

Incorrect interpretation of imaging is relatively infrequent as a cause of malpractice litigation compared with failure to diagnose aneurysms in the clinical setting by neurosurgeons, emergency physicians, and primary care providers.

Rupture of a previously undiagnosed intracranial aneurysm during endoscopic dacryocystorhinostomy: A case report

Endoscopic endonasal dacryocystorhinostomy (EE-DCR) is an effective treatment for dacryocystitis. Aneurysmal rupture is generally not considered a complication of EE-DCR under general anesthesia. Here, we present a patient with intracerebral and subarachnoid hemorrhage secondary to the rupture of an undiagnosed intracranial aneurysm during EE-DCR. Clinicians should be aware of such fatal complications when using any vasoconstrictor intraoperatively.

Deep learning-based recognition and segmentation of intracranial aneurysms under small sample size

The manual identification and segmentation of intracranial aneurysms (IAs) involved in the 3D reconstruction procedure are labor-intensive and prone to human errors. To meet the demands for routine clinical management and large cohort studies of IAs, fast and accurate patient-specific IA reconstruction becomes a research Frontier. In this study, a deep-learning-based framework for IA identification and segmentation was developed, and the impacts of image pre-processing and convolutional neural network (CNN) architectures on the framework's performance were investigated. Three-dimensional (3D) segmentation-dedicated architectures, including 3D UNet, VNet, and 3D Res-UNet were evaluated. The dataset used in this study included 101 sets of anonymized cranial computed tomography angiography (CTA) images with 140 IA cases. After the labeling and image pre-processing, a training set and test set containing 112 and 28 IA lesions were used to train and evaluate the convolutional neural network mentioned above. The performances of three convolutional neural networks were compared in terms of training performance, segmentation performance, and segmentation efficiency using multiple quantitative metrics. All the convolutional neural networks showed a non-zero voxel-wise recall (V-Recall) at the case level. Among them, 3D UNet exhibited a better overall segmentation performance under the relatively small sample size. The automatic segmentation results based on 3D UNet reached an average V-Recall of 0.797 ± 0.140 (3.5% and 17.3% higher than that of VNet and 3D Res-UNet), as well as an average dice similarity coefficient (DSC) of 0.818 ± 0.100, which was 4.1%, and 11.7% higher than VNet and 3D Res-UNet. Moreover, the average Hausdorff distance (HD) of the 3D UNet was 3.323 ± 3.212 voxels, which was 8.3% and 17.3% lower than that of VNet and 3D Res-UNet. The three-dimensional deviation analysis results also showed that the segmentations of 3D UNet had the smallest deviation with a max distance of +1.4760/-2.3854 mm, an average distance of 0.3480 mm, a standard deviation (STD) of 0.5978 mm, a root mean square (RMS) of 0.7269 mm. In addition, the average segmentation time (AST) of the 3D UNet was 0.053s, equal to that of 3D Res-UNet and 8.62% shorter than VNet. The results from this study suggested that the proposed deep learning framework integrated with 3D UNet can provide fast and accurate IA identification and segmentation.

RAPID Aneurysm: Artificial intelligence for unruptured cerebral aneurysm detection on CT angiography

OBJECTIVES

Cerebral aneurysms may result in significant morbidity and mortality. Identification of these aneurysms on CT Angiography (CTA) studies is critical to guide patient treatment. Artificial intelligence platforms to assist with automated aneurysm detection are of high interest. We determined the performance of a semi-automated artificial intelligence software program (RAPID Aneurysm) for the detection of cerebral aneurysms.

MATERIALS AND METHODS

RAPID Aneurysm was used to detect retrospectively the presence of cerebral aneurysms in CTA studies performed between January 2019 and December 2020. The gold standard was aneurysm presence and location as determined by the consensus of three expert neuroradiologists. Aneurysm detection accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and positive and negative likelihood ratios by RAPID Aneurysm were determined.

RESULTS

51 patients (mean age, 56±15; 24 women [47.1%]) with a single CTA were included. A total of 60 aneurysms were identified. RAPID Aneurysm had a sensitivity of 0.950 (95% CI: 0.863-0.983), specificity of 1.000 (95% CI: 0.996-1.000), a positive predictive value (PPV) of 1.000 (95% CI: 0.937-1.000), a negative predictive value (NPV) of 0.997 (95% CI: 0.991-0.999), and an accuracy of 0.997 (95% CI: 0.991-0.999) for cerebral aneurysm detection.

CONCLUSIONS

RAPID Aneurysm is highly accurate for the detection of cerebral aneurysms on CTA.

A Review of Artificial Intelligence in Cerebrovascular Disease Imaging: Applications and Challenges

BACKGROUND

A variety of emerging medical imaging technologies based on artificial intelligence have been widely applied in many diseases, but they are still limitedly used in the cerebrovascular field even though the diseases can lead to catastrophic consequences.

OBJECTIVE

This work aims to discuss the current challenges and future directions of artificial intelligence technology in cerebrovascular diseases through reviewing the existing literature related to applications in terms of computer-aided detection, prediction and treatment of cerebrovascular diseases.

METHODS

Based on artificial intelligence applications in four representative cerebrovascular diseases including intracranial aneurysm, arteriovenous malformation, arteriosclerosis and moyamoya disease, this paper systematically reviews studies published between 2006 and 2021 in five databases: National Center for Biotechnology Information, Elsevier Science Direct, IEEE Xplore Digital Library, Web of Science and Springer Link. And three refinement steps were further conducted after identifying relevant literature from these databases.

RESULTS

For the popular research topic, most of the included publications involved computer-aided detection and prediction of aneurysms, while studies about arteriovenous malformation, arteriosclerosis and moyamoya disease showed an upward trend in recent years. Both conventional machine learning and deep learning algorithms were utilized in these publications, but machine learning techniques accounted for a larger proportion.

CONCLUSION

Algorithms related to artificial intelligence, especially deep learning, are promising tools for medical imaging analysis and will enhance the performance of computer-aided detection, prediction and treatment of cerebrovascular diseases.

Pituitary MRI Standard and Advanced Sequences: Role in the Diagnosis and Characterization of Pituitary Adenomas

Pituitary adenomas (PAs) represent the most frequently found lesions in the sellar region; however, several other lesions may be encountered in this region, such as meningiomas, craniopharyngiomas, and aneurysms. High-quality imaging is fundamental for diagnosis, characterization, and guidance of treatment planning of PAs. Sellar magnetic resonance imaging (MRI) is considered the imaging modality of choice for the evaluation of lesions in the sella turcica. The sellar MRI standard protocol includes coronal and sagittal T1-weighted spin-echo sequencing with and without gadolinium-based contrast agent and coronal T2-weighted (T2w) fast-spin echo sequencing. A systematic MRI approach to the pituitary region generally provides information that includes the size and shape of the PA, the presence of cysts or hemorrhage within the tumor, its relationship with the optic pathways and surrounding structures, potential cavernous sinus invasion, sphenoid sinus pneumatization type, and differential diagnosis with other sellar lesions. The standard protocol is sufficient for the evaluation of most cases; however, some advanced techniques (susceptibility imaging, diffusion-weighted imaging, 3D T2w high-resolution sequences, magnetic resonance elastography, perfusion-weighted imaging) may render additional information, which may be important for some cases. In this "approach to the patient" manuscript, we will discuss the use of standard and advanced MRI sequences in the diagnosis and characterization of PAs, including MRI features associated with treatment response that may aid in presurgical evaluation and planning, and red flags that may point to an alternative diagnosis.

OTO-Net: An Automated MRA Image Segmentation Network for Intracranial Aneurysms

Intracranial aneurysms are local dilations of the cerebral blood vessels; people with intracranial aneurysms have a high risk to cause bleeding in the brain, which is related to high mortality and morbidity rates. Accurate detection and segmentation of intracranial aneurysms from Magnetic Resonance Angiography (MRA) images are essential in the clinical routine. Manual annotations used to assess the intracranial aneurysms on MRA images are substantial interobserver variability for both aneurysm detection and assessment of aneurysm size and growth. Many prior automated segmentation works have focused their efforts on tackling the problem, but there is still room for performance improvement due to the significant variability of lesions in the location, size, structure, and morphological appearance. To address these challenges, we propose a novel One-Two-One Fully Convolutional Networks (OTO-Net) for intracranial aneurysms automated segmentation in MRA images. The OTO-Net uses full convolution to achieve intracranial aneurysms automated segmentation through the combination of downsampling, upsampling, and skip connection. In addition, loss ensemble is used as the objective function to steadily improve the backpropagation efficiency of the network structure during the training process. We evaluated the proposed OTO-Net on one public benchmark dataset and one private dataset. Our proposed model can achieve the automated segmentation accuracy with 98.37% and 97.86%, average surface distances with 1.081 and 0.753, dice similarity coefficients with 0.9721 and 0.9813, and Hausdorff distance with 0.578 and 0.642 on these two datasets, respectively.

Identification of Potential Core Genes for the Rupture of Intracranial Aneurysms by a Bioinformatics Analysis

Background: Previous studies, using autopsy and angiography, have shown that 3.6–6% of the population have intracranial aneurysms, and the rupture of aneurysm can lead to brain dysfunction or even death in patients.

Methods: To explore potential preventional target genes for the ruptured of aneurysm, we analyze three gene expression datasets (GSE13353, GSE15629 and GSE54083) derived from the GEO database. We confirm DEGs associated with the unrupture of aneurysms by R package. DAVID version provides functional classification and annotation analyses of associated genes, including GO and KEGG pathway. PPI of these DEGs is analyzed based on the string database and visualized by Cytoscape software. DEGs are verified by qRT-PCR using samples isolated from the patients.

Results: 249 overlapping DEGs, including 96 up-regulated genes and 153 down-regulated genes are screened using the Venn diagram webtool. The GO term and KEGG pathways analysis results indicate that these DEGs are mainly enriched in protein phosphorylation, apoptotic process and inflammatory response in the BP term and focal adhesion, thyroid hormone signaling pathway, ErbB signaling pathway, cytokine-cytokine receptor interaction and some disease processes in the KEGG pathways. 6 candidates are confirmed by Cytoscape software and qRT-PCR, including APP, JUN, GSK3B, ErbB2, PPBP and THBS1.

Conclusions: Our data and previous studies show that ErbB2 and THBS1 are crucial to prevent aneurysm rupture, while APP, JUN, GSK3B and PPBP performs the opposite role, and further experiments are needed to verify these findings.

Initial investigation of the use of angiographic parametric imaging for early prognosis of delayed cerebral ischemia in patients with subarachnoid hemorrhage

PURPOSE

Subarachnoid Hemorrhage (SAH) is a lethal hemorrhagic stroke that account for 25% of cerebrovascular deaths. As a result of the initial bleed, a chain of physiological events are initiated which may lead to Delayed Cerebral Ischemia (DCI). As of now we have no diagnostic capability to identify patients which may present DCI a few weeks after initial presentation. We propose to investigate whether a data driven approach using angiographic parametric imaging (API) may predict occurrence of the DCI.

MATERIALS AND METHODS

Digital Subtraction Angiographic (DSA) sequences from 125 SAH patients were used retrospectively to perform API assessment of the entire brain hemisphere where the hemorrhage was detected. Four Regions of Interests (ROIs) were placed to extract five average API biomarkers in the lateral and AP DSAs. Data driven analysis using Logistic Regression was performed for various API parameters and ROIs to find the optimal configuration to maximize the prognosis accuracy. Each model performance was evaluated using area under the curve of the receiver operator characteristic (AUROC).

RESULTS

Data driven approach with API has a 60% accuracy predicting DCI occurrence. We determined that location of the ROI for extraction of the API parameters is very important for the data driven model performance. Normalizing the values using the inlet velocities for each patient yield higher and more consistent results. Single API biomarkers models had poor prediction accuracies, barely better than chance.

CONCLUSIONS

This effectiveness exploratory study demonstrates for the first time, that prognosis of the DCI in SAH patients, is feasible and warrants a more in-depth investigation.

Optimizing Small, Low-Risk, Unruptured Intracranial Aneurysm Treatment Using Game Theory

The incidental diagnosis of unruptured intracranial aneurysms has been increasing in the past several decades. A significant proportion represent small, low-risk, unruptured intracranial aneurysms for which there is equipoise on whether to offer treatment or conservative management. Given this uncertainty, patients may not always be comfortable with their physicians' recommendations. Herein, we use game theory to study the interactions between physicians and patients to determine how conflict and cooperation affect the management of small, low-risk, unruptured intracranial aneurysms. We constructed a game theory model of the interaction between physicians and patients with respect to decision-making for a small, low-risk, unruptured intracranial aneurysm in an asymptomatic patient when there is perceived equipoise between whether to treat or manage conservatively. Assuming that both the physician and patient are rational and eliciting individual patient preferences is not practical, the physician should play the game based on an ex ante probability of meeting a patient with a certain type of preference. This recommendation means that the expectations of the physician regarding the patient's preferences should guide the decision to offer treatment or conservative management as a first option for a small, asymptomatic, low-risk, unruptured intracranial aneurysm for which there is clinical equipoise.

Modifiable risk factors for intracranial aneurysms: Evidence from genetic studies

Background:

Intracranial aneurysm (IA) is a crucial health concern with limited strategies for prevention and treatment.

Aim:

To identify potentially modifiable risk factors, such as socioeconomic, behaviors, dietary, and cardiometabolic factors, for IA and its subtypes.

Methods:

Summary statistics for IA were derived from a genome-wide association study with an overall 79,429 participants. Single nucleotide polymorphisms associated with modifiable risk factors at genome-wide significance ( P = 5 × 10–8) were used as instrumental variables. The inverse-variance-weighted method, weighted-median method, Mendelian randomization (MR)-Egger regression, MR-Pleiotropy RESidual Sum and Outlier, and multivariable MR analyses were performed to evaluate the effect estimates.

Results:

Genetically predicted educational attainment, insomnia, smoking, and systolic and diastolic blood pressure (SBP and DBP) were significantly associated with the risk of IA. The odds ratios (ORs) were 0.44 (95% confidence interval (CI): 0.37–0.52) for educational attainment, 1.15 (95% CI: 1.08–1.23) for insomnia, 1.56 (95% CI: 1.38–1.75) for smoking initiation, 2.69 (95% CI: 1.77–4.07) for cigarette per day, 2.65 (95% CI: 1.72–4.08) for lifetime smoking, 1.07 (95% CI: 1.06–1.09), and 1.06 (95% CI: 1.04–1.10) for SBP and DBP, respectively. Similar effect estimates were observed for unruptured IAs and aneurysmal subarachnoid hemorrhage.

Conclusions:

This study provided genetic evidence that several modifiable risk factors, including blood pressure, smoking, educational attainment, and insomnia were associated with the risk of IA.

NLRP3 inhibition attenuates early brain injury and delayed cerebral vasospasm after subarachnoid hemorrhage

BACKGROUND

The NLRP3 inflammasome is a critical mediator of several vascular diseases through positive regulation of proinflammatory pathways. In this study, we defined the role of NLRP3 in both the acute and delayed phases following subarachnoid hemorrhage (SAH). SAH is associated with devastating early brain injury (EBI) in the acute phase, and those that survive remain at risk for developing delayed cerebral ischemia (DCI) due to cerebral vasospasm. Current therapies are not effective in preventing the morbidity and mortality associated with EBI and DCI. NLRP3 activation is known to drive IL-1β production and stimulate microglia reactivity, both hallmarks of SAH pathology; thus, we hypothesized that inhibition of NLRP3 could alleviate SAH-induced vascular dysfunction and functional deficits.

METHODS

We studied NLRP3 in an anterior circulation autologous blood injection model of SAH in mice. Mice were randomized to either sham surgery + vehicle, SAH + vehicle, or SAH + MCC950 (a selective NLRP3 inhibitor). The acute phase was studied at 1 day post-SAH and delayed phase at 5 days post-SAH.

RESULTS

NLRP3 inhibition improved outcomes at both 1 and 5 days post-SAH. In the acute (1 day post-SAH) phase, NLRP3 inhibition attenuated cerebral edema, tight junction disruption, microthrombosis, and microglial reactive morphology shift. Further, we observed a decrease in apoptosis of neurons in mice treated with MCC950. NLRP3 inhibition also prevented middle cerebral artery vasospasm in the delayed (5 days post-SAH) phase and blunted SAH-induced sensorimotor deficits.

CONCLUSIONS

We demonstrate a novel association between NLRP3-mediated neuroinflammation and cerebrovascular dysfunction in both the early and delayed phases after SAH. MCC950 and other NLRP3 inhibitors could be promising tools in the development of therapeutics for EBI and DCI.

A Modification to a Murine Model for Intracranial Aneurysm Formation and Rupture

Between 3.6% and 6.0% of the population has an intracranial aneurysm. The mechanisms underlying intracranial aneurysm formation and rupture are not fully known. Several rodent models have been developed to better understand intracranial aneurysm pathophysiology. Hypertension, hemodynamic changes, and vessel injury are all necessary for aneurysm induction; however, multiple invasive procedures may disrupt an animal’s physiology. Therefore, we hypothesized that our method for inducing hypertension could be modified to create a simpler model. We previously developed a highly reproducible murine model of intracranial aneurysm formation and rupture that involves hemodynamic changes through ligation of the left common carotid artery, vessel wall degradation using elastase and a lysyl oxidase inhibitor, and hypertension through a high-salt diet, continuous angiotensin II infusion, and right renal artery ligation. In order to create a simpler model, we sought to eliminate renal artery ligation. We assessed aneurysm formation, aneurysm rupture, and blood pressure in two separate cohorts of C57BL/6 mice: one cohort underwent our model as above, while another cohort did not receive right renal artery ligation. Our results demonstrate that intracranial aneurysm formation and rupture rates did not differ between each group. Further, the blood pressures between cohorts did not differ at various timepoints in the model. Both cohorts, however, did have a significant increase in blood pressure from baseline, suggesting that renal artery ligation is not needed for inducing hypertension. These findings demonstrate that our murine model can be modified to eliminate right renal artery ligation. Thus, we propose this modification to our murine model for studying intracranial aneurysm pathophysiology.

Aneurysmal Subarachnoid Hemorrhage in Patients with Coronavirus Disease 2019 (COVID-19): A Case Series

Objective

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is a pressing public health issue. Although most cases do not result in severe illness requiring hospitalization, there is increasing evidence that SARS-CoV-2–induced inflammation can exacerbate pre-existing diseases. We sought to describe the characteristics of patients with aneurysmal subarachnoid hemorrhage who were actively or very recently infected with SARS-CoV-2.

Methods

We reviewed subarachnoid hemorrhage cases of patients who also were positive for SARS-CoV-2 at 5 high-volume cerebrovascular centers in the United States from March 2020 to January 2021. Cases of aneurysmal subarachnoid hemorrhage were analyzed.

Results

A total of 10 patients were identified, consisting of 5 women (50%) and 5 men (50%). Median age was 38.5 years. Four of the 10 patients (40%) were asymptomatic with respect to SARS-CoV-2–related symptoms, 3 patients (30%) had mild-to-moderate symptoms, and 3 patients (30%) had severe coronavirus disease 2019 (COVID-19), with pneumonia and sepsis. Of the 10 cases, 4 had dissecting pseudoaneurysms (40%), 3 in the posterior circulation and 1 in the anterior circulation. Among 6 saccular/blister aneurysms, 4 (67%) were ≤4 mm in largest diameter.

Conclusions

Our experience with aneurysmal subarachnoid hemorrhage in patients positive for COVID-19 reveals a possibly distinct pattern compared with traditional aneurysmal subarachnoid hemorrhage, namely a high frequency of small aneurysms, dissecting pseudoaneurysms, and young patients.

Clinical and Morphological Characteristics of Ruptured Small (<5 mm) Posterior Communicating Artery Aneurysms

Context:

Small intracranial aneurysms (IAs) are considered to have a low risk of rupture; however, in clinical practice, we often encounter patients with subarachnoid hemorrhage (SAH) due to rupture of small IAs.

Aims:

This study aims to clarify the clinical and morphological characteristics of ruptured small IA, focusing on posterior communicating artery (PCoA) aneurysms as a prone site.

Settings and Design:

We retrospectively reviewed 102 consecutive patients with SAH due to ruptured PCoA aneurysm who underwent microsurgical or endovascular aneurysm repair between April 2013 and March 2018.

Subjects and Methods:

All PCoA aneurysms were diagnosed using three-dimensional rotation angiography or three-dimensional computed tomography angiography. Information regarding the following clinical characteristics was collected: age, sex, past medical history, current smoking, antithrombotic therapy, multiplicity, hydrocephalus, intracerebral hemorrhage, intraventricular hemorrhage, and World Federation of Neurosurgical Societies (WFNS) Grade on admission.

Statistical Analysis Used:

We analyzed factors of ruptured small IA, focusing on PCoA aneurysms using univariate and multivariate regression analyses.

Results:

Univariate and multivariate analyses revealed that low aspect ratio (AR) (odds ratio [OR] = 0.33, P = 0.01) and nonfetal type of PCoA (OR = 0.31, P = 0.02) might be independent characteristics of ruptured small PCoA aneurysms. However, age, sex, past medical history, WFNS grade, and treatment outcome were not different between the small and nonsmall PCoA aneurysms. The aneurysm size was not associated to the selection of treatment, proportion of complications, and treatment outcome.

Conclusions:

In cases of ruptured PCoA aneurysms, low AR and nonfetal type of PCoA might be associated with rupture of small aneurysms.

Comparing methods of detecting and segmenting unruptured intracranial aneurysms on TOF-MRAS: The ADAM challenge

Accurate detection and quantification of unruptured intracranial aneurysms (UIAs) is important for rupture risk assessment and to allow an informed treatment decision to be made. Currently, 2D manual measures used to assess UIAs on Time-of-Flight magnetic resonance angiographies (TOF-MRAs) lack 3D information and there is substantial inter-observer variability for both aneurysm detection and assessment of aneurysm size and growth. 3D measures could be helpful to improve aneurysm detection and quantification but are time-consuming and would therefore benefit from a reliable automatic UIA detection and segmentation method. The Aneurysm Detection and segMentation (ADAM) challenge was organised in which methods for automatic UIA detection and segmentation were developed and submitted to be evaluated on a diverse clinical TOF-MRA dataset. A training set (113 cases with a total of 129 UIAs) was released, each case including a TOF-MRA, a structural MR image (T1, T2 or FLAIR), annotation of any present UIA(s) and the centre voxel of the UIA(s). A test set of 141 cases (with 153 UIAs) was used for evaluation. Two tasks were proposed: (1) detection and (2) segmentation of UIAs on TOF-MRAs. Teams developed and submitted containerised methods to be evaluated on the test set. Task 1 was evaluated using metrics of sensitivity and false positive count. Task 2 was evaluated using dice similarity coefficient, modified hausdorff distance (95^th percentile) and volumetric similarity. For each task, a ranking was made based on the average of the metrics. In total, eleven teams participated in task 1 and nine of those teams participated in task 2. Task 1 was won by a method specifically designed for the detection task (i.e. not participating in task 2). Based on segmentation metrics, the top two methods for task 2 performed statistically significantly better than all other methods. The detection performance of the top-ranking methods was comparable to visual inspection for larger aneurysms. Segmentation performance of the top ranking method, after selection of true UIAs, was similar to interobserver performance. The ADAM challenge remains open for future submissions and improved submissions, with a live leaderboard to provide benchmarking for method developments at https://adam.isi.uu.nl/.

Using a Convolutional Neural Network and Convolutional Long Short-term Memory to Automatically Detect Aneurysms on 2D-DSA Images (Preprint)

Background

It is hard to distinguish cerebral aneurysms from overlapping vessels in 2D digital subtraction angiography (DSA) images due to these images’ lack of spatial information.

Objective

The aims of this study were to (1) construct a deep learning diagnostic system to improve the ability to detect posterior communicating artery aneurysms on 2D DSA images and (2) validate the efficiency of the deep learning diagnostic system in 2D DSA aneurysm detection.

Methods

We proposed a 2-stage detection system. First, we established the region localization stage to automatically locate specific detection regions of raw 2D DSA sequences. Second, in the intracranial aneurysm detection stage, we constructed a bi-input+RetinaNet+convolutional long short-term memory (C-LSTM) framework to compare its performance for aneurysm detection with that of 3 existing frameworks. Each of the frameworks had a 5-fold cross-validation scheme. The receiver operating characteristic curve, the area under the curve (AUC) value, mean average precision, sensitivity, specificity, and accuracy were used to assess the abilities of different frameworks.

Results

A total of 255 patients with posterior communicating artery aneurysms and 20 patients without aneurysms were included in this study. The best AUC values of the RetinaNet, RetinaNet+C-LSTM, bi-input+RetinaNet, and bi-input+RetinaNet+C-LSTM frameworks were 0.95, 0.96, 0.92, and 0.97, respectively. The mean sensitivities of the RetinaNet, RetinaNet+C-LSTM, bi-input+RetinaNet, and bi-input+RetinaNet+C-LSTM frameworks and human experts were 89% (range 67.02%-98.43%), 88% (range 65.76%-98.06%), 87% (range 64.53%-97.66%), 89% (range 67.02%-98.43%), and 90% (range 68.30%-98.77%), respectively. The mean specificities of the RetinaNet, RetinaNet+C-LSTM, bi-input+RetinaNet, and bi-input+RetinaNet+C-LSTM frameworks and human experts were 80% (range 56.34%-94.27%), 89% (range 67.02%-98.43%), 86% (range 63.31%-97.24%), 93% (range 72.30%-99.56%), and 90% (range 68.30%-98.77%), respectively. The mean accuracies of the RetinaNet, RetinaNet+C-LSTM, bi-input+RetinaNet, and bi-input+RetinaNet+C-LSTM frameworks and human experts were 84.50% (range 69.57%-93.97%), 88.50% (range 74.44%-96.39%), 86.50% (range 71.97%-95.22%), 91% (range 77.63%-97.72%), and 90% (range 76.34%-97.21%), respectively.

Conclusions

According to our results, more spatial and temporal information can help improve the performance of the frameworks. Therefore, the bi-input+RetinaNet+C-LSTM framework had the best performance when compared to that of the other frameworks. Our study demonstrates that our system can assist physicians in detecting intracranial aneurysms on 2D DSA images.

Intracranial aneurysm and coarctation of the aorta: prevalence in the current era

BACKGROUND

A 10% prevalence of intracranial aneurysms in patients with coarctation of the aorta has been described in a few studies. Our objective is to describe the rate of intracranial aneurysm detection in patients with coarctation of the aorta in the current era. We hypothesise that, with earlier detection and coarctation of the aorta intervention, the rate of intracranial aneurysm is lower than previously reported and screening imaging may only be warranted in older patients or patients with certain risk factors.

METHODS

This is a retrospective study of 102 patients aged 13 years and older with coarctation who underwent brain computed tomography angiography, magnetic resonance imaging (MRI), or magnetic resonance angiography between January, 2000 and February, 2018.

RESULTS

The median age of coarctation repair was 4.4 months (2 days-47 years) and the initial repair was primarily surgical (90.2%). There were 11 former smokers, 4 current smokers, and 13 patients with ongoing hypertension. Imaging modalities included computed tomography angiography (13.7%), MRI (41.2%), and magnetic resonance angiography (46.1%), performed at a median age of 33.3 years, 22.4 years, and 25 years, respectively. There were 42 studies performed for screening, 48 studies performed for neurologic symptoms, and 12 studies performed for both screening and symptoms. There were no intracranial aneurysms detected in this study.

CONCLUSIONS

These results suggest that the rate of intracranial aneurysms may be lower than previously reported and larger studies should explore the risk of intracranial aneurysms in coarctation of the aorta in the current era.

Fully automated detection and segmentation of intracranial aneurysms in subarachnoid hemorrhage on CTA using deep learning

In aneurysmal subarachnoid hemorrhage (aSAH), accurate diagnosis of aneurysm is essential for subsequent treatment to prevent rebleeding. However, aneurysm detection proves to be challenging and time-consuming. The purpose of this study was to develop and evaluate a deep learning model (DLM) to automatically detect and segment aneurysms in patients with aSAH on computed tomography angiography. In this retrospective single-center study, three different DLMs were trained on 68 patients with 79 aneurysms treated for aSAH (2016–2017) using five-fold-cross-validation. Their outputs were combined to a single DLM via ensemble-learning. The DLM was evaluated on an independent test set consisting of 185 patients with 215 aneurysms (2010–2015). Independent manual segmentations of aneurysms in a 3D voxel-wise manner by two readers (neurosurgeon, radiologist) provided the reference standard. For aneurysms > 30 mm³ (mean diameter of ~ 4 mm) on the test set, the DLM provided a detection sensitivity of 87% with false positives (FPs)/scan of 0.42. Automatic segmentations achieved a median dice similarity coefficient (DSC) of 0.80 compared to the reference standard. Aneurysm location (anterior vs. posterior circulation; P = .07) and bleeding severity (Fisher grade ≤ 3 vs. 4; P = .33) did not impede detection sensitivity or segmentation performance. For aneurysms > 100 mm³ (mean diameter of ~ 6 mm), a sensitivity of 96% with DSC of 0.87 and FPs/scan of 0.14 were obtained. In the present study, we demonstrate that the proposed DLM detects and segments aneurysms > 30 mm³ in patients with aSAH with high sensitivity independent of cerebral circulation and bleeding severity while producing FP findings of less than one per scan. Hence, the DLM can potentially assist treating physicians in aSAH by providing automated detection and segmentations of aneurysms.

From 2D to 4D Phase-Contrast MRI in the Neurovascular System: Will It Be a Quantum Jump or a Fancy Decoration?

Considering the crosstalk between the flow and vessel wall, hemodynamic assessment of the neurovascular system may offer a well-integrated solution for both diagnosis and management by adding prognostic significance to the standard CT/MR angiography. 4D flow MRI or time-resolved 3D velocity-encoded phase-contrast MRI has long been promising for the hemodynamic evaluation of the great vessels, but challenged in clinical studies for assessing intracranial vessels with small diameter due to long scan times and low spatiotemporal resolution. Current accelerated MRI techniques, including parallel imaging with compressed sensing and radial k-space undersampling acquisitions, have decreased scan times dramatically while preserving spatial resolution. 4D flow MRI visualized and measured 3D complex flow of neurovascular diseases such as aneurysm, arteriovenous shunts, and atherosclerotic stenosis using parameters including flow volume, velocity vector, pressure gradients, and wall shear stress. In addition to the noninvasiveness of the phase contrast technique and retrospective flow measurement through the wanted windows of the analysis plane, 4D flow MRI has shown several advantages over Doppler ultrasound or computational fluid dynamics. The evaluation of the flow status and vessel wall can be performed simultaneously in the same imaging modality. This article is an overview of the recent advances in neurovascular 4D flow MRI techniques and their potential clinical applications in neurovascular disease. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.

Therapeutic Potential of Heme Oxygenase-1 in Aneurysmal Diseases

Abdominal aortic aneurysm (AAA) and intracranial aneurysm (IA) are serious arterial diseases in the aorta and brain, respectively. AAA and IA are associated with old age in males and females, respectively, and if rupture occurs, they carry high morbidity and mortality. Aneurysmal subarachnoid hemorrhage (SAH) due to IA rupture has a high rate of complication and fatality. Despite these severe clinical outcomes, preventing or treating these devastating diseases remains an unmet medical need. Inflammation and oxidative stress are shared pathologies of these vascular diseases. Therefore, therapeutic strategies have focused on reducing inflammation and reactive oxygen species levels. Interestingly, in response to cellular stress, the inducible heme oxygenase-1 (HO-1) is highly upregulated and protects against tissue injury. HO-1 degrades the prooxidant heme and generates molecules with antioxidative and anti-inflammatory properties, resulting in decreased oxidative stress and inflammation. Therefore, increasing HO-1 activity is an attractive option for therapy. Several HO-1 inducers have been identified and tested in animal models for preventing or alleviating AAA, IA, and SAH. However, clinical trials have shown conflicting results. Further research and the development of highly selective HO-1 regulators may be needed to prevent the initiation and progression of AAA, IA, or SAH.

Neurosurgery in Contemporary Medical Dramas: How Grey's Anatomy & Co. May Affect Perception of Neurosurgery in the Media

BACKGROUND

 Neurosurgery is a common topic in contemporary medical dramas. This study aimed to examine depictions of several neurosurgical diseases and techniques as well as the perception of the personality of neurosurgeons in the media, focusing on their impact on the physician-patient relationship.

METHODS

 TV series and movies with a main focus on neurosurgeons and/or neurosurgical diseases were identified by consulting the International Movie Database (IMDb).

RESULTS

 After investigation of many TV series and movies, we identified five main topics: vascular neurosurgery, neuro-oncology, neurointensive care, neurosurgical techniques, and neurosurgeon's personality. The portrayal of neurosurgery in medical drama is characterized to a large extent by sensationalism, a lot of misinformation, and an unfavorable portrayal of neurosurgeons, although it is assumed that expert advice was sought in advance of every production.

CONCLUSIONS

 Considering the popularity of medical dramas and movies dealing with medical topics, we must consider the general public's picture of neurosurgery to be widely influenced by the media.

Spontaneous Spinal Subarachnoid Hemorrhage from a Ruptured Radiculopial Artery Aneurysm

BACKGROUND

Spontaneous spinal subarachnoid hemorrhage is an uncommon entity and is even rarer when secondary to intraspinal ruptured aneurysm. The clinical presentation of these cases usually includes back pain and headache; however, we report a unique case in which the patient became acutely paraplegic.

CASE DESCRIPTION

A 54-year-old woman initially presented with thunderclap headache and interscapular pain. There was no evidence of subarachnoid hemorrhage on noncontrast computed tomography of the head, but lumbar puncture revealed xanthochromia-positive cerebrospinal fluid. Subsequent computed tomography angiography identified a small right superior hypophyseal aneurysm. The patient then became acutely paraplegic during neurosurgical assessment in the emergency department. Urgent magnetic resonance imaging revealed extensive intradural hemorrhage in the cervicothoracic region, prompting emergent surgical decompression. At surgery, this hemorrhage was noted in a subarachnoid location, but no specific source was identified. Postoperative spinal digital subtraction angiography revealed an intraspinal aneurysm of the posterior spinal circulation involving the left T2 radiculopial artery, which was resected in a subsequent uneventful operation within the same hospital admission.

CONCLUSIONS

This unique clinical case highlights a rare cause of spontaneous acute paralysis and further demonstrates the safety of obliterating an intraspinal aneurysm via operative resection.

Deep learning based detection of intracranial aneurysms on digital subtraction angiography: A feasibility study

BACKGROUND

Digital subtraction angiography is the gold standard for detecting and characterising aneurysms. Here, we assess the feasibility of commercial-grade deep learning software for the detection of intracranial aneurysms on whole-brain anteroposterior and lateral 2D digital subtraction angiography images.

MATERIAL AND METHODS

Seven hundred and six digital subtraction angiography images were included from a cohort of 240 patients (157 female, mean age 59 years, range 20-92; 83 male, mean age 55 years, range 19-83). Three hundred and thirty-five (47%) single frame anteroposterior and lateral images of a digital subtraction angiography series of 187 aneurysms (41 ruptured, 146 unruptured; average size 7±5.3 mm, range 1-5 mm; total 372 depicted aneurysms) and 371 (53%) aneurysm-negative study images were retrospectively analysed regarding the presence of intracranial aneurysms. The 2D data was split into testing and training sets in a ratio of 4:1 with 3D rotational digital subtraction angiography as gold standard. Supervised deep learning was performed using commercial-grade machine learning software (Cognex, ViDi Suite 2.0). Monte Carlo cross validation was performed.

RESULTS

Intracranial aneurysms were detected with a sensitivity of 79%, a specificity of 79%, a precision of 0.75, a F1 score of 0.77, and a mean area-under-the-curve of 0.76 (range 0.68-0.86) after Monte Carlo cross-validation, run 45 times.

CONCLUSION

The commercial-grade deep learning software allows for detection of intracranial aneurysms on whole-brain, 2D anteroposterior and lateral digital subtraction angiography images, with results being comparable to more specifically engineered deep learning techniques.

Identification of potential key pathways, genes and circulating markers in the development of intracranial aneurysm based on weighted gene co-expression network analysis

Background: Intracranial aneurysm (IA) is a disease resulted from weak brain control, characterized by local expansion or dilation of brain artery. This study aimed to construct a gene co-expression network by Weighted Gene Correlation Network Analysis (WGCNA) to explore the potential key pathways and genes for the development of IA.Method: Six IA-related gene expression data sets were downloaded from the Gene Expression Omnibus (GEO) database for identifying differentially expressed genes (DEGs). WGCNA was used to identify modules associated with IA. Functional enrichment analysis was used to explore the potential biological functions. ROC analysis was used to find markers for predicting IA.Results: Purple, greenyellow and yellow modules were significantly associated with unruptured intracranial aneurysms, while blue and turquoise modules were significantly associated with ruptured intracranial aneurysms. Functional modules significantly related to IA were enriched in Ribosome, Glutathione metabolism, cAMP signalling pathway, Lysosome, Glycosaminoglycan degradation and other pathways. CD163, FCEREG, FPR1, ITGAM, NLRC4, PDG, and TYROBP were up-regulated ruptured intracranial aneurysms and serum, these genes were potential circulating markers for predicting IA rupture.Conclusions: Potential IA-related key pathways, genes and circulating markers were identified for predicting IA rupture by WGCNA analysis.

Protective Effects of Obstructive Sleep Apnea on Outcomes After Subarachnoid Hemorrhage: A Nationwide Analysis

BACKGROUND

Obstructive sleep apnea (OSA) is typically associated with an increased risk of cardiovascular and cerebrovascular disease. Recent studies, however, have suggested that hypercapnia and chronic intermittent hypoxia may potentially provide protection against ischemic events like stroke.

OBJECTIVE

To evaluate the impact of OSA with presentation, hospital course, and treatment outcomes of patients with subarachnoid hemorrhage (SAH).

METHODS

Data for patients with SAH between the years 2011 and 2015 were extracted from the Nationwide Inpatient Sample (NIS) and stratified based on diagnosis codes for OSA. Univariate analysis was used to assess the prevalence of comorbidities in OSA patients diagnosed with SAH and several covariates, including patient demographics, aneurysmal treatment, in-hospital morality rate, length of stay, and costs. Multivariate logistic regression models analyzed the relationship between several comorbidities, including OSA, tobacco use, and hypertension, and poor outcomes after SAH.

RESULTS

Data from 49 265 SAH patients were used in this study, of which 2408 (4.9%) also had a concomitant OSA diagnosis. Patients with OSA compared to all other SAH patients had a significantly lower in-hospital mortality rate, as well as statistically significant lower odds of vasospasm, stroke, and poor outcomes. Additionally, hypercholesterolemia, obesity, and tobacco use disorder were also associated with more favorable outcomes.

CONCLUSION

SAH patients with OSA are significantly less likely to have a poor outcome when compared to non-OSA patients, despite having an increased risk of several comorbidities.

Experimental Analysis of Intra-luminal Pressure by Contrast Injection during Mechanical Thrombectomy: Simulation of Rupture Risk of Hidden Cerebral Aneurysm in Tandem Occlusion with Blind Alley

Mechanical thrombectomy using a retrograde approach is performed for tandem occlusion of the internal carotid artery (ICA). In our patient, a guiding catheter was easily passed by the stenosed lesion despite severe stenosis at the ICA origin. Therefore, we aimed to recanalize the occlusion of the terminal ICA without angioplasty for the stenosed lesion. When contrast was injected, a massive extravasation of contrast from the C2 portion of the ICA was observed. It was speculated that the bleeding was caused by rupture of an aneurysm at that site due to increased intra-arterial pressure caused by the contrast injection to a blind alley, which was created by a wedged guiding catheter at severe stenosis at the ICA origin and the occlusion of the terminal ICA. Our simulation experiment using a silicon vascular model in this situation demonstrated that the elevation of intra-arterial pressure in such blind alley reached over 50, 100, and 200 mmHg by injection of contrast from a microcatheter, a 4-Fr inner catheter, and a 9-Fr balloon-guiding catheter, respectively. When a retrograde approach is planned for tandem occlusion of the ICA, even when the proximal lesion is easily passed, prior angioplasty for the proximal lesion should be considered to avoid wedging by catheter.

Ratio of IL-8 in CSF versus Serum Is Elevated in Patients with Unruptured Brain Aneurysm

Only scarce data pertaining to interleukin 8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) chemokines in human aneurysm can be found in the current literature. Therefore, the aim of this study was the evaluation of cerebrospinal fluid (CSF) and serum IL-8 and MCP-1 concentration in unruptured intracranial aneurysm (UIA) patients (n = 25) compared to the control group (n = 20). IL-8 and MCP-1 concentrations were measured with ELISA method. We demonstrated that CSF IL-8 concentration of UIA patients is significantly higher (p < 0.001) than that presented in the serum, which can indicate its local synthesis within central nervous system. CSF IL-8 concentration was also significantly related to aneurysm size, which may reflect the participation of IL-8 in the formation and development of brain aneurysms. IL-8 Quotient (CSF IL-8 divided by serum IL-8) in UIA patients was statistically higher compared to control individuals (p = 0.045). However, the diagnostic utility analysis did not equivocally indicate the diagnostic usefulness of the IL-8 Quotient evaluation in brain aneurysm patients. Nevertheless, this aspect requires further study.

Imaging features of vertebral artery fenestration

PURPOSE

Vertebral artery fenestration (VAF) is a rare congenital vascular anomaly which has been associated with intracranial aneurysm. VAF can share some similar imaging features with vertebral artery dissection (VAD), which may confound diagnosis of the latter on CT and MR angiography. The purpose of this investigation is to assess the prevalence of VAF, evaluate its association with other vascular anomalies, and identify imaging features to help in distinguishing VAF and VAD.

METHODS

Using keyword search on CTA and MRA head and neck imaging reports from 2010 to 2017, cases of VAF and VAD were retrospectively identified and imaging was reviewed. Imaging features including laterality; vertebral segment; length of affected segment; presence, number, and caliber of lumen(s); and presence of other vascular abnormalities were recorded for all cases and subsequently compared using Pearson's chi-squared test to assess for significant differences between the groups. Patient age, gender, and clinical presentations were also recorded.

RESULTS

Of 64,888 CT and MR angiographic examinations performed, VAF was identified in 67 (0.1%) and VAD in 54 (0.1%) patients. Compared with VADs, VAFs were shorter in length (p < 0.001), wider in luminal diameter (p < 0.001), more likely to occur at the V4 segment (p < 0.01), more likely to have two distinct lumens rather than one (p < 0.01), and less likely to present post-trauma (p < 0.01). Coexisting intracranial aneurysms were identified in 9% of patients with VAF.

CONCLUSION

VAFs, although rare, can be readily distinguished from VADs on angiographic imaging. Diagnosis of VAF should prompt review for intracranial aneurysm.

Perioperative rupture risk of unruptured intracranial aneurysms in cardiovascular surgery

Although unruptured intracranial aneurysms are increasingly being diagnosed incidentally, perioperative rupture risk of unruptured intracranial aneurysm in patients undergoing cardiovascular surgery remains unclear. Therefore, we conducted an observational study to assess the prevalence and perioperative rupture risk of unruptured intracranial aneurysm in patients undergoing cardiovascular surgery. Adult patients (n = 4864) who underwent cardiovascular surgery between January 2010 and December 2016 were included. We assessed the prevalence of unruptured intracranial aneurysms in these patients using preoperative neurovascular imaging. The incidence of postoperative 30-day subarachnoid haemorrhage from aneurysmal rupture was investigated in patients undergoing cardiovascular surgery with unruptured intracranial aneurysm. Postoperative outcomes were compared between patients with unruptured intracranial aneurysm and those without unruptured intracranial aneurysm. Of the 4864 patients (39.6% females; mean ± standard deviation age, 62.3 ± 11.3 years), 353 patients had unruptured intracranial aneurysms (prevalence rate, 7.26%; 95% confidence interval, 6.52-8.06%). Of these, eight patients received surgical or endovascular treatment before surgery and 345 patients underwent cardiovascular surgery with unruptured intracranial aneurysms. Within 30 days postoperatively, subarachnoid haemorrhage occurred only in one patient, and the cumulative postoperative 30-day subarachnoid haemorrhage incidence was 0.29% (95% confidence interval, 0.01% to 1.61%). The Kaplan-Meier estimated subarachnoid haemorrhage probabilities according to the unruptured intracranial aneurysm rupture risk scores were not higher than the previously reported risk in the general population. There were no significant differences in postoperative subarachnoid haemorrhage-free survival, haemorrhagic stroke-free survival, in-hospital mortality, and hospital length of stay between patients with unruptured intracranial aneurysm and those without unruptured intracranial aneurysm. In conclusion, the prevalence of unruptured intracranial aneurysm in patients undergoing cardiovascular surgery is higher than in the general population. However, incidentally detected unruptured intracranial aneurysms are not linked to an increased risk of subarachnoid haemorrhage or adverse postoperative outcomes. These findings may help determine the optimal management of unruptured intracranial aneurysms before cardiovascular surgery.

Epidemiological analysis of 1404 patients with intracranial aneurysm followed in a single Brazilian institution

Background:

We sought to evaluate the epidemiology of intracranial aneurysms in relation to location, gender, age, presence of multiple aneurysms, and comorbidities in the Brazilian population.

Methods:

We performed a prospective analysis of a cohort of 1404 patients diagnosed with intracranial aneurysm admitted to the Hospital das Clinicas of the University of Sao Paulo, a referral hospital for the treatment of cerebrovascular diseases in Brazil. Patients admitted between September 2009 and September 2018 with radiological diagnosis of intracranial aneurysm were included in the study.

Results:

A total of 2251 aneurysms were diagnosed. Females accounted for 1090 aneurysms (77.6%) and the mean age at diagnosis was 54.9 years (ranging 15–88). The most common location was middle cerebral artery (MCA) with 593 aneurysms (26.3%) followed by anterior cerebral artery (ACA) with 417 aneurysms (18.5%) and internal carotid artery in the posterior communicating segment with 405 aneurysms (18.0%). Males had higher rates of ACA aneurysms (29.7%) while females had higher rates of MCA aneurysms (26.1%). Sorting by size, 492 aneurysms were <5 mm (21.8%), 1524 measured 5–10 mm (67.7%), 119 size 11–24 mm (5.3%), and 116 were >24 mm (5.2%). The occurrence of multiple aneurysms was associated with female gender (P < 0.001) and smoking (P < 0.001), but not with hypertension (P = 0.121).

Conclusion:

In this population, the occurrence of intracranial aneurysm is related to several factors, including gender, age, smoking, and hypertension. Our study brought to light important characteristics of a large number of Brazilian patients regarding epidemiology, location, size, and multiplicity of intracranial aneurysms.

Meta-Analysis of Pterional Versus Supraorbital Keyhole Approach for Clipping Intracranial Aneurysms: Direct Comparison of Approach-Related Complications

BACKGROUND

The supraorbital keyhole approach (SKA) and pterional approach (PA) have been recommended for clipping intracranial aneurysms (IAs). We conducted a meta-analysis to systematically and comprehensively compare the clinical outcomes between the 2 approaches.

METHODS

We retrieved potential academic studies that had compared the clinical outcomes of SKA and PA for clipping IAs from the Cochrane Library, Medline, PubMed, and EMBASE databases. The references of the identified studies were carefully reviewed to ensure that all available documents had been included in the present study. The meta-analysis was conducted in accordance with the acknowledged PRISMA (prioritized reported items for systematic review and meta-analysis) guidelines.

RESULTS

A total of 8 studies with 1016 participants were included in our study. Of these 1016 patients with IAs, 518 were assigned to the SKA group and 498 to the PA group. Our results showed that the SKA is preferable for clipping IAs compared with the PA because of its shorter operative time (weighted mean difference, -3.163; 95% confidence interval [CI], -5.577 to -0.749; P = 0.01) and length of stay, especially for the patients with unruptured IAs (weighted mean difference, -52.107; 95% CI, -81.597 to -22.618). However, a lower risk of postoperative infection was found in the SKA group (4.6% vs. 8.5%; odds ratio, 0.398; 95% CI, 0.186-0.850; P = 0.017), which seemed to derive from the ruptured IAs (OR, 0.330; 95% CI, 0.136-0.800; P = 0.014). However, no significant difference was found in the incidence of frontal sinus opening, completed occlusion, procedural complications, intraoperative rupture, postoperative hematoma, or cerebral vessel spasm.

CONCLUSIONS

The SKA was associated with a shorter length of stay and operation time and a lower risk of postoperative infection. Hence, the SKA seems to be equally effective and safe for clipping IAs compared with PA and should be recommended for surgeons who have acquired sufficient experience with this technique owing to its advantages compared with the PA.

Fully Printed, Wireless, Stretchable Implantable Biosystem toward Batteryless, Real-Time Monitoring of Cerebral Aneurysm Hemodynamics

This study introduces a high-throughput, large-scale manufacturing method that uses aerosol jet 3D printing for a fully printed stretchable, wireless electronics. A comprehensive study of nanoink preparation and parameter optimization enables a low-profile, multilayer printing of a high-performance, capacitance flow sensor. The core printing process involves direct, microstructured patterning of biocompatible silver nanoparticles and polyimide. The optimized fabrication approach allows for transfer of highly conductive, patterned silver nanoparticle films to a soft elastomeric substrate. Stretchable mechanics modeling and seamless integration with an implantable stent display a highly stretchable and flexible sensor, deployable by a catheter for extremely low-profile, conformal insertion in a blood vessel. Optimization of a transient, wireless inductive coupling method allows for wireless detection of biomimetic cerebral aneurysm hemodynamics with the maximum readout distance of 6 cm through meat. In vitro demonstrations include wireless monitoring of flow rates (0.05-1 m s-1) in highly contoured and narrow human neurovascular models. Collectively, this work shows the potential of the printed biosystem to offer a high throughput, additive manufacturing of stretchable electronics with advances toward batteryless, real-time wireless monitoring of cerebral aneurysm hemodynamics.

Management of Tiny Unruptured Intracranial Aneurysms: A Comparative Effectiveness Analysis

Importance

Unruptured intracranial aneurysms (UIAs) are relatively common in the general population and are being increasingly diagnosed; a significant proportion are tiny (≤3 mm) aneurysms. There is significant heterogeneity in practice and lack of clear guidelines on the management of incidental, tiny UIAs. It is important to quantify the implications of different management strategies in terms of health benefits to patients.

Objective

To evaluate the effectiveness of routine treatment (aneurysm coiling) vs 3 strategies for imaging surveillance compared with no preventive treatment or routine follow-up of tiny UIAs.

Design, Setting, and Participants

A decision-analytic model-based comparative effectiveness analysis was conducted from May 1 to June 30, 2017, using inputs from the medical literature. PubMed searches were performed to identify relevant literature for all key model inputs, each of which was derived from the clinical study with the most robust data and greatest applicability. Analysis included 10 000 iterations simulating adult patients with incidental detections of UIAs 3 mm or smaller and no history of subarachnoid hemorrhage.

Interventions

The following 5 management strategies for tiny UIAs were evaluated: annual magnetic resonance angiography (MRA) screening, biennial MRA screening, MRA screening every 5 years, aneurysm coiling and follow-up, and no treatment or preventive follow-up.

Main Outcomes and Measures

A Markov decision model for lifetime rupture was constructed from a societal perspective per 10 000 patients with incidental, tiny UIAs. Outcomes were assessed in terms of quality-adjusted life-years. Probabilistic, 1-way, and 2-way sensitivity analyses were performed.

Results

In this analysis of 10 000 iterations simulating adult patients with a mean age of 50 years, the base-case calculation shows that the management strategy of no treatment or preventive follow-up has the highest health benefit (mean [SD] quality-adjusted life-years, 19.40 [0.31]). Among the management strategies that incorporate follow-up imaging, MRA every 5 years is the best strategy with the next highest effectiveness (mean [SD] quality-adjusted life-years, 18.05 [0.62]). The conclusion remains robust in probabilistic and 1-way sensitivity analyses. No routine follow-up remains the optimal strategy when the annual growth rate and risk of rupture of growing aneurysms are varied. When the annual risk of rupture of nongrowing UIAs is less than 1.7% (0.23% in base case scenario), no follow-up is the optimal strategy. If annual risk of rupture is more than 1.7%, coiling should be performed directly.

Conclusions and Relevance

Given the current literature, no preventive treatment or imaging follow-up is the most effective strategy in patients with aneurysms that are 3 mm or smaller, resulting in better health outcomes. More aggressive imaging surveillance for aneurysm growth or preventive treatment should be reserved for patients with a high risk of rupture. Given these findings, it is important to critically evaluate the appropriateness of current clinical practices, and potentially determine specific guidelines to reflect the most effective management strategy for patients with incidental, tiny UIAs.

Higher risk of intracranial aneurysms and subarachnoid haemorrhage in siblings of families with intracranial aneurysms

Introduction

First-degree relatives of patients with familial aneurysmal subarachnoid hemorrhage have an increased risk of unruptured intracranial aneurysms and aneurysmal subarachnoid hemorrhage. We assessed whether the type of kinship of first-degree relatives of aneurysmal subarachnoid hemorrhage patients influences this risk.

Patients and methods

We used all available data from the prospectively collected database of families consulting our outpatient clinic between 1994-2016. We constructed pedigrees for all families with ≥2 first-degree relatives with aneurysmal subarachnoid hemorrhage or unruptured intracranial aneurysms. The proband was defined as the first family member with aneurysmal subarachnoid hemorrhage who sought medical attention. We compared both the proportion of aneurysmal subarachnoid hemorrhage and unruptured intracranial aneurysms in proband's first-degree relatives by calculating relative risks (RR) with children as the reference.

Results

We studied 154 families with 1,105 first-degree relatives of whom 146 had aneurysmalsubarachnoid hemorrhage. Unruptured intracranial aneurysms were identified in 63 (19%) of the 326 screened relatives. Siblings had a higher risk of aneurysmal subarachnoid hemorrhage (RR:1.62, 95% CI:1.12–2.38) and parents a lower risk (RR:0.44, 95% CI:0.24–0.81) than children. Siblings also had a higher risk of unruptured intracranial aneurysms (RR:2.28, 95% CI:1.23–4.07, age-adjusted RR:2.04, 95% CI:1.07–3.92) than children.

Conclusion: Siblings of patients with aneurysmal subarachnoid hemorrhage have a significanthigher risk of both unruptured intracranial aneurysms and aneurysmal subarachnoid hemorrhage and parents have a lower risk of aneurysmal subarachnoid hemorrhage than children.

Discussion: Type of kinship is a relevant factor to consider in risk prediction and screening advice in families with familial aneurysmal subarachnoid hemorrhage.

Performance of a Deep-Learning Neural Network to Detect Intracranial Aneurysms from 3D TOF-MRA Compared to Human Readers

PURPOSE

To study the clinical potential of a deep learning neural network (convolutional neural networks [CNN]) as a supportive tool for detection of intracranial aneurysms from 3D time-of-flight magnetic resonance angiography (TOF-MRA) by comparing the diagnostic performance to that of human readers.

METHODS

In this retrospective study a pipeline for detection of intracranial aneurysms from clinical TOF-MRA was established based on the framework DeepMedic. Datasets of 85 consecutive patients served as ground truth and were used to train and evaluate the model. The ground truth without annotation was presented to two blinded human readers with different levels of experience in diagnostic neuroradiology (reader 1: 2 years, reader 2: 12 years). Diagnostic performance of human readers and the CNN was studied and compared using the χ²-test and Fishers' exact test.

RESULTS

Ground truth consisted of 115 aneurysms with a mean diameter of 7 mm (range: 2-37 mm). Aneurysms were categorized as small (S; <3 mm; N = 13), medium (M; 3-7 mm; N = 57), and large (L; >7 mm; N = 45) based on the diameter. No statistically significant differences in terms of overall sensitivity (OS) were observed between the CNN and both of the human readers (reader 1 vs. CNN, P = 0.141; reader 2 vs. CNN, P = 0.231). The OS of both human readers was improved by combination of each readers' individual detections with the detections of the CNN (reader 1: 98% vs. 95%, P = 0.280; reader 2: 97% vs. 94%, P = 0.333).

CONCLUSION

A CNN is able to detect intracranial aneurysms from clinical TOF-MRA data with a sensitivity comparable to that of expert radiologists and may have the potential to improve detection rates of incidental findings in a clinical setting.

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.