Influence of physiological conditions on hemodynamics of internal carotid artery aneurysms.

This study investigates the influence of body physiology on the rupture risk of cerebral saccular aneurysms. Comprehensive hemodynamic analyses were conducted using computational fluid dynamics to assess the potential for aneurysm rupture under three physiological conditions: rest, normal activity, and exercise. Contours of wall shear stress, oscillatory shear index, and pressure were analyzed and compared to identify regions at high risk of rupture. Additionally, statistical analysis was performed to evaluate the rupture risk of aneurysms. Blood flow dynamics during the peak systolic phase were also examined under these conditions. Our findings indicate that the dome area, where blood pressure is highest and the incoming blood flow first contacts the aneurysm sac, is the critical region with a heightened risk of rupture.

Causal relationship between mitochondrial-associated proteins and cerebral aneurysms: a Mendelian randomization study.

Background: Cerebral aneurysm is a high-risk cerebrovascular disease with a poor prognosis, potentially linked to multiple factors. This study aims to explore the association between mitochondrial-associated proteins and the risk of cerebral aneurysms using Mendelian randomization (MR) methods. Methods: We used GWAS summary statistics from the IEU Open GWAS project for mitochondrial-associated proteins and from the Finnish database for cerebral aneurysms (uIA, aSAH). The association between mitochondrial-associated exposures and cerebral aneurysms was evaluated using MR-Egger, weighted mode, IVW, simple mode and weighted median methods. Reverse MR assessed reverse causal relationship, while sensitivity analyses examined heterogeneity and pleiotropy in the instrumental variables. Significant causal relationship with cerebral aneurysms were confirmed using FDR correction. Results: Through MR analysis, we identified six mitochondrial proteins associated with an increased risk of aSAH: AIF1 (OR: 1.394, 95% CI: 1.109-1.752, p = 0.0044), CCDC90B (OR: 1.318, 95% CI: 1.132-1.535, p = 0.0004), TIM14 (OR: 1.272, 95% CI: 1.041-1.553, p = 0.0186), NAGS (OR: 1.219, 95% CI: 1.008-1.475, p = 0.041), tRNA PusA (OR: 1.311, 95% CI: 1.096-1.569, p = 0.003), and MRM3 (OR: 1.097, 95% CI: 1.016-1.185, p = 0.0175). Among these, CCDC90B, tRNA PusA, and AIF1 demonstrated a significant causal relationship with an increased risk of aSAH (FDR q < 0.1). Three mitochondrial proteins were associated with an increased risk of uIA: CCDC90B (OR: 1.309, 95% CI: 1.05-1.632, p = 0.0165), tRNA PusA (OR: 1.306, 95% CI: 1.007-1.694, p = 0.0438), and MRM3 (OR: 1.13, 95% CI: 1.012-1.263, p = 0.0303). In the reverse MR study, only one mitochondrial protein, TIM14 (OR: 1.087, 95% CI: 1.004-1.177, p = 0.04), showed a causal relationship with aSAH. Sensitivity analysis did not reveal heterogeneity or pleiotropy. The results suggest that CCDC90B, tRNA PusA, and MRM3 may be common risk factors for cerebral aneurysms (ruptured and unruptured), while AIF1 and NAGS are specifically associated with an increased risk of aSAH, unrelated to uIA. TIM14 may interact with aSAH. Conclusion: Our findings confirm a causal relationship between mitochondrial-associated proteins and cerebral aneurysms, offering new insights for future research into the pathogenesis and treatment of this condition.

Coil Embolization for Cerebral Aneurysm Using Low Pulse Rate Fluoroscopy.

Although coil embolization is commonly perceived as a minimally invasive procedure, the associated radiation exposure cannot be disregarded. To date, no specific study has investigated radiation exposure during coil embolization. This study aimed to investigate the potential of lowering the pulse rate to decrease radiation exposure during coil embolization while maintaining patient safety. Radiation data and clinical features of 70 patients who underwent coil embolization between 2015 and 2020 were retrospectively analyzed. Since July 2017, the pulse rate was regulated from 7.5 to 4 frames per second (f/s). Statistical analyses were performed to examine the correlation between pulse rate and radiation exposure. Out of the 70 procedures, 30 were performed at the standard pulse rate (7.5 f/s), and 40 were performed at the lower pulse rate (4 f/s). In the lower-pulse-rate group, the absorbed dose to the patient (AK) was 2580.7 (±217) mGy, whereas in the standard-pulse-rate group, it was 4760 (±411.1). Both the dose-area product (DAP) and AK were substantially reduced in the low pulse rate group (p = 0.000002). There was a significant correlation between DAP and AK and pulse rate (p = 0.004, p = 0.0017, respectively). Moreover, there was no significant correlation between pulse rate and perioperative complications. Our findings suggest that using a lower pulse rate (4 f/s) can effectively reduce radiation exposure during coil embolization for cerebral aneurysms while ensuring patient safety.

Spinal Subdural Hematoma Secondary to Ruptured Internal Carotid Artery Ophthalmic Segment Aneurysm: A Case Report and Narrative Review.

Spinal subdural hematoma (SSDH) is a rare condition where the exact pathology is unclear; coagulopathy, bleeding disorders, trauma, and iatrogenic causes are frequently associated with SSDH. SARS-CoV-2 infection and COVID-19 vaccines are unusual causes of SSDH, as reported by multiple studies. Here, we present a rare case report and a narrative review of SSDH resulting from a ruptured cerebral aneurysm. A 53-year-old female presented with an acute, severe suboccipital headache and neck and back pain without radiculopathy. Investigations for cardiovascular diseases and brain images were unremarkable. Further investigation revealed an SSDH extending from T1 to S2. Negative spinal angiography led to a cerebral angiogram, identifying an internal carotid artery ophthalmic segment aneurysm that was successfully treated with endovascular stent-assisted coiling. This case scenario of anterior circulation cerebral aneurysmal rupture manifesting as an isolated SSDH is unique compared to previously reported cases of SSDH resulting from cerebral aneurysms. This case highlights the importance of considering aneurysmal rupture in SSDH cases with no apparent underlying pathology to prevent neurological deficits. Early detection and intervention in such cases can prevent serious neurological deficits and improve patient outcomes.

Patient-specific arterial wall generation for intracranial aneurysms with a variable and a near realistic vessel wall thickness for FSI studies.

BACKGROUND AND OBJECTIVE: Imaging methodologies such as, computed tomography (CT) aid in three-dimensional (3D) reconstruction of patient-specific aneurysms. The radiological data is useful in understanding their location, shape, size, and disease progression. However, there are serious impediments in discerning the blood vessel wall thickness due to limitations in the current imaging modalities. This further restricts the ability to perform high-fidelity fluid structure interaction (FSI) studies for an accurate assessment of rupture risk. FSI studies would require the arterial wall mesh to be generated to determine realistic maximum allowable wall stresses by performing coupled calculations for the hemodynamic forces with the arterial walls. METHODS: In the present study, a novel methodology is developed to geometrically model variable vessel wall thickness for the lumen isosurface extracted from CT scan slices of patient-specific aneurysms based on clinical and histopathological inputs. FSI simulations are carried out with the reconstructed models to assess the importance of near realistic wall thickness model on rupture risk predictions. RESULTS: During surgery, clinicians often observe translucent vessel walls, indicating the presence of thin regions. The need to generate variable vessel wall thickness model, that embodies the wall thickness gradation, is closer to such clinical observations. Hence, corresponding FSI simulations performed can improve clinical outcomes. Considerable differences in the magnitude of instantaneous wall shear stresses and von Mises stresses in the walls of the aneurysm was observed between a uniform wall thickness and a variable wall thickness model. CONCLUSION: In the present study, a variable vessel wall thickness generation algorithm is implemented. It was shown that, a realistic wall thickness modeling is necessary for an accurate prediction of the shear stresses on the wall as well as von Mises stresses in the wall. FSI simulations are performed to demonstrate the utility of variable wall thickness modeling.

Vasa vasorum: The role in intracranial physiology and pathophysiology.

Background: Vasa vasorum (VVs) is a Latin word representing vessels of vessels. VVs are usually found on the adventitia of the parent vessel and infrequently reach the media and intima, depending on the size and type of the parent vessels and physiological and pathological conditions. The VVs include arteries, capillaries, veins, and lymphatic vessels, involving the oxygenation and nourishment of the vessel's wall to sustain its healthy state. Accumulated studies have revealed that VVs are involved in various intracranial lesions, including atherosclerotic diseases, aneurysms, and shunt diseases. The current review aims to review and integrate past and recent findings and knowledge on VVs and to facilitate our understanding of VVs and intracranial pathology involving VVs. Methods: A literature review was carried out with a focus on the role of VVs by searching the Pubmed database. Results: We identified 71 articles that discuss the role of VVs. We discussed the anatomical structure, physiological significance, and pathological significance of the VV. Conclusion: VV is not only involved in the nutrition and metabolism of the vascular wall but is also deeply involved in the pathogenesis of inflammation, ischemia, and thrombosis of the vascular wall. In addition, in the central nervous system, intracranial vascular wall nutrient particularities and VVs are closely related to the pathogenesis of cerebral aneurysms, subarachnoid hemorrhage, arteriovenous shunt disease, atherosclerotic lesions, and other conditions.

Dimethyl Fumarate Mediates Sustained Vascular Smooth Muscle Cell Remodeling in a Mouse Model of Cerebral Aneurysm.

Cerebral aneurysms (CA) are a type of vascular disease that causes significant morbidity and mortality with rupture. Dysfunction of the vascular smooth muscle cells (VSMCs) from circle of Willis (CoW) vessels mediates CA formation, as they are the major cell type of the arterial wall and play a role in maintaining vessel integrity. Dimethyl fumarate (DMF), a first-line oral treatment for relapsing-remitting multiple sclerosis, has been shown to inhibit VSMC proliferation and reduce CA formation in a mouse model. Potential unwanted side effects of DMF on VSMC function have not been investigated yet. The present study characterizes the impact of DMF on VSMC using single-cell RNA-sequencing (scRNA-seq) in CoW vessels following CA induction and further explores its role in mitochondrial function using in vitro VSMC cultures. Two weeks of DMF treatment following CA induction impaired the transcription of the glutathione redox system and downregulated mitochondrial respiration genes in VSMCs. In vitro, DMF treatment increased lactate formation and enhanced the mitochondrial production of reactive oxygen species (ROS). These effects rendered VSMCs vulnerable to oxidative stress and led to mitochondrial dysfunction and enhancement of apoptosis. Taken together, our data support the concept that the DMF-mediated antiproliferative effect on VSMCs is linked to disturbed antioxidative functions resulting in altered mitochondrial metabolism. This negative impact of DMF treatment on VSMCs may be linked to preexisting alterations of cerebrovascular function due to renal hypertension. Therefore, before severe adverse effects emerge, it would be clinically relevant to develop indices or biomarkers linked to this disturbed antioxidative function to monitor patients undergoing DMF treatment.

A Case of Multiple Intracranial Hemorrhages due to a Ruptured Neoplastic Cerebral Aneurysm Secondary to Metastasis of Poorly Differentiated Parotid Gland Carcinoma.

Neoplastic cerebral aneurysms (NCAs) are rare. This study reported a case of an NCA secondary to a poorly differentiated carcinoma of the parotid gland. An 84-year-old Japanese woman undergoing treatment for parotid gland cancer was admitted to our hospital with headache and progressive loss of consciousness. Based on computed tomography (CT) and CT angiography (CTA), a diagnosis of subarachnoid hemorrhage due to rupture of a left posterior inferior cerebellar artery aneurysm was made, and emergency aneurysmectomy was performed. Pathological examination of the resected aneurysm showed an NCA secondary to parotid carcinoma. After the aneurysmectomy, her condition stabilized; however, 33 days later, the patient developed an intracerebral hemorrhage, and a new aneurysm was confirmed in the right middle cerebral artery. To the best of our knowledge, there have been no previous reports on cases of NCAs secondary to parotid carcinoma. The pathology and clinical course strongly suggest that NCAs derived from malignant tumors may have an aggressive course.

CTA-based 3D virtual model for preoperative simulation and intraoperative neuronavigation in the surgical treatment of distal anterior cerebral artery aneurysms.

OBJECTIVE: This study aims to assess the efficacy and limitations of Computed Tomography Angiography (CTA)-based 3D virtual models for preoperative simulation and intraoperative neuronavigation in the surgical treatment of Distal Anterior Cerebral Artery (DACA) Aneurysms. METHODS: A retrospective observational study was conducted, analyzing patients who underwent surgical clipping of DACA aneurysms via an interhemispheric approach from 2016 to 2022. Outcomes measured included qualitative analyses of 3D reconstructions against actual intraoperative anatomy, neuronavigator accuracy, 6-month modified Rankin Scale (mRS), complete exclusion rates, and surgical complications. Patient demographics, clinical characteristics, surgical timing, and intraoperative data were meticulously documented for analysis. RESULTS: Fifteen patients were included in the study, with a mean age of 52 years. The mean Hunt-Hess score at admission was 2.2, encompassing 2 unruptured and 13 ruptured aneurysms. Intraoperative anatomical visualization perfectly matched the preoperative 3D model in 13 cases, with discrepancies in two. Neuronavigation demonstrated a mean accuracy of 1.76 mm, remaining consistent in 14 patients, and accurately tracking the planned trajectory. Postoperative complications occurred in 26.5 % of patients, including two fatalities, with no navigation-related complications. Incomplete aneurysm occlusion was observed in one case. The mean mRS score at 6 months was 2.46. CONCLUSIONS: The employment of 3D CTA for preoperative simulation and intraoperative neuronavigation holds significant potential in enhancing the surgical management of DACA aneurysms. Despite some discrepancies and technical limitations, the overall precision of preoperative simulations and the strategic value of intraoperative neuronavigation highlight their utility in improving surgical outcomes.

Letter to editor: Bridging the gap: robotic applications in cerebral aneurysms neurointerventions - a systematic review.

The letter critically evaluates the role of robotic applications in cerebral aneurysm neurointerventions, synthesizing a diverse array of studies to elucidate both the potential benefits and inherent limitations of this emerging technology. The review highlights the advancements in precision, efficiency, and patient outcomes facilitated by robotic platforms, while also acknowledging challenges such as the steep learning curve and the need for further research to establish long-term efficacy and cost-effectiveness. By navigating through the complexities of robotic-assisted neurosurgery, the review provides valuable insights into the transformative potential of robotics in optimizing treatment paradigms and improving patient care.

Digital Subtraction Angiography of Cerebral Arteries: Influence of Cranial Dimensions on X-ray Tube Performance.

(1) Background. Digital subtraction angiography (DSA) is indispensable for diagnosing cerebral aneurysms due to its superior imaging precision. However, optimizing X-ray parameters is crucial for accurate diagnosis, with X-ray tube settings significantly influencing image quality. Understanding the relationship between skull dimensions and X-ray parameters is pivotal for tailoring imaging protocols to individual patients. (2) Methods. A retrospective analysis of DSA data from a single center was conducted, involving 251 patients. Cephalometric measurements and statistical analyses were performed to assess correlations between skull dimensions and X-ray tube parameters (voltage and current). (3) Results. The study revealed significant correlations between skull dimensions and X-ray tube parameters, highlighting the importance of considering individual anatomical variations. Gender-based differences in X-ray parameters were observed, emphasizing the need for personalized imaging protocols. (4) Conclusions. Personalized approaches to DSA imaging, integrating individual anatomical variations and gender-specific differences, are essential for optimizing diagnostic outcomes. While this study provides valuable insights, further research across multiple centers and diverse imaging equipment is warranted to validate these findings.

Influence of Perioperative Three-Dimensional Computed Tomography (CT) Angiography and Surgical Clipping for Unruptured Cerebral Aneurysms on Renal Function in Patients with Chronic Kidney Disease.

BACKROUND: Surgical clipping is a valuable treatment option for unruptured intracranial aneurysms in patients with chronic kidney disease (CKD). However, the comprehensive impact of clipping and perioperative three-dimensional computed tomography angiography (3D-CTA) on renal function remains unclear. This study aimed to evaluate the effects of perioperative 3D-CTA and surgical clipping on renal function in patients with CKD. METHODS: We retrospectively analyzed 529 patients who underwent surgical clipping and perioperative 3D-CTA. An estimated glomerular filtration rate (eGFR) < 60 was defined as CKD. Patients were stratified according to their renal function (group 1: eGFR ≥60, group 2: 45 ≤ eGFR <60, group 3: 30 ≤ eGFR <45, group 4: eGFR <30 ml/min/1.73 m2), and eGFR was assessed preoperatively and 1 week and several months postoperatively. RESULTS: Of the 529 patients, 442 did not have CKD and 87 had CKD. Hypertension, hyperlipidemia, and hyperuricemia were significantly more common in those with CKD. After the surgery and perioperative series of 3D-CTA, renal function deterioration was not observed in any group, whether in the acute or chronic postoperative period. Notably, eGFR significantly increased in groups 2 (66.7 ± 10.1, P < 0.01) and 3 (48.9 ± 9.2, P = 0.02) 1 week postoperatively, despite the CKD. CONCLUSIONS: Surgical clipping of unruptured intracranial aneurysms and perioperative 3D-CTA with normal-dose contrast media did not impair renal function in patients with CKD. These results could be valuable in determining treatment strategies for those with CKD and intracranial aneurysms.

Neuro-Behcet's Disease and Its Association With Cerebral Aneurysms and Subarachnoid Hemorrhage: A Case Report.

Behçet's disease is a rare autoimmune condition characterized by systemic vasculitis, an inflammation of blood vessels, with an unknown etiology. It has varied clinical presentations. Herein, we present the case of a 31-year-old male patient with neuro-Behçet disease who presented with subarachnoid hemorrhage and microaneurysms.

Craniovertebral and spinal adhesive arachnoiditis: a late complication of ruptured vertebral and posterior inferior cerebellar arteries aneurysms.

BACKGROUND: Adhesive arachnoiditis is a rare yet serious complication that may occur following subarachnoid hemorrhage (SAH). In this circumstance, it is mainly due to ruptured vertebral artery (VA) or posterior inferior artery (PICA) aneurysms. It disrupts cerebrospinal fluid (CSF) flow leading to complications such as spinal arachnoiditis, syringomyelia, trapped 4th ventricle, or a combination of these conditions. Evidence for effective treatment strategies is currently limited. We aimed to review the epidemiology, clinical characteristics, treatment, complications, outcomes, and prognosis of cranio-vertebral junction and spinal adhesive arachnoiditis resulting from ruptured VA and PICA aneurysms. METHODS: This study involved a comprehensive literature review and complemented by our own case. We focused on adult cases of arachnoiditis, syringomyelia, and trapped 4th ventricle with SAH caused by ruptured VA or PICA aneurysms, excluding cases unrelated to these aneurysms and those with insufficient data. RESULTS: The study included 22 patients, with a mean age of 52.4 years. Symptoms commonly manifest within the first year after SAH and timely diagnosis requires a high index of suspicion. Treatment approaches included lysis of adhesions and various shunt procedures. Most patients showed improvement post-treatment, though symptom recurrence is significant. CONCLUSION: Adhesive arachnoiditis is a critical complication following SAH, most commonly from ruptured VA and PICA aneurysms. Early detection and individualized treatment based on the type of arachnoiditis and CSF flow impact are crucial for effective management. This study underscores the need for tailored treatment strategies and further research in this field.

[Russian study on brain aneurysm surgery: a continuation (RIHA II)]. / Rossiiskoe issledovanie po khirurgii anevrizm golovnogo mozga: prodolzhenie (RIKhA II).

OBJECTIVE: To assess the main performance indicators of neurosurgical departments in surgical treatment of cerebral aneurysms in the Russian Federation. MATERIAL AND METHODS: We analyzed 22 neurosurgical departments (19 regional and 3 federal hospitals) in 2017 and 2021. The study enrolled 6.135 patients including 3.160 ones in 2017 and 2.975 ones in 2021. We studied the features of surgical treatment of cerebral aneurysms in different volume hospitals and factors influencing postoperative outcomes. RESULTS: The number of surgeries for cerebral aneurysms decreased from 2.950 in 2017 to 2.711 in 2021. Postoperative mortality rate was 6.3% and 5.6%, respectively. The number of microsurgical interventions decreased from 60% in 2017 to 48% in 2021. The share of endovascular interventions increased from 40% to 52%, respectively. Endovascular embolization was accompanied by stenting in 55% of cases. Simultaneous revascularization was carried out in 2% of cases. In 2021, the number of patients undergoing surgery in acute period of hemorrhage increased to 70% (in 2017 - 61%). The number of hospitals performing more than 50 surgical interventions for cerebral aneurysms annually increased from 14 in 2017 to 17 in 2021. CONCLUSION: Certain changes in neurosurgical service occurred in 2021 compared to 2017. Lower number of surgical interventions for cerebral aneurysms, most likely caused by the COVID-19 pandemic, is accompanied by lower postoperative mortality. Endovascular interventions and revascularization techniques became more common. The number of surgeries in acute period after aneurysm rupture and hospitals performing more than 50 surgical interventions for cerebral aneurysms annually increased.

A mendelian randomization study investigates the causal relationship between immune cell phenotypes and cerebral aneurysm.

Background: Cerebral aneurysms (CAs) are a significant cerebrovascular ailment with a multifaceted etiology influenced by various factors including heredity and environment. This study aimed to explore the possible link between different types of immune cells and the occurrence of CAs. Methods: We analyzed the connection between 731 immune cell signatures and the risk of CAs by using publicly available genetic data. The analysis included four immune features, specifically median brightness levels (MBL), proportionate cell (PC), definite cell (DC), and morphological attributes (MA). Mendelian randomization (MR) analysis was conducted using the instrumental variables (IVs) derived from the genetic variation linked to CAs. Results: After multiple test adjustment based on the FDR method, the inverse variance weighted (IVW) method revealed that 3 immune cell phenotypes were linked to the risk of CAs. These included CD45 on HLA DR+NK (odds ratio (OR), 1.116; 95% confidence interval (CI), 1.001-1.244; p = 0.0489), CX3CR1 on CD14- CD16- (OR, 0.973; 95% CI, 0.948-0.999; p = 0.0447). An immune cell phenotype CD16- CD56 on NK was found to have a significant association with the risk of CAs in reverse MR study (OR, 0.950; 95% CI, 0.911-0.990; p = 0.0156). Conclusion: Our investigation has yielded findings that support a substantial genetic link between immune cells and CAs, thereby suggesting possible implications for future clinical interventions.

Influence of vortical structures on fibrin clot formation in cerebral aneurysms: A two-dimensional computational study.

Thrombosis is an important contributor to cerebral aneurysm growth and progression. A number of sophisticated multiscale and multiphase in silico models have been developed with a view towards interventional planning. Many of these models are able to account for clotting outcomes, but do not provide detailed insight into the role of flow during clot development. In this study, we present idealised, two-dimensional in silico cerebral fibrin clot model based on computational fluid dynamics (CFD), biochemical modelling and variable porosity, permeability, and diffusivity. The model captures fibrin clot growth in cerebral aneurysms over a period at least 1000 s in five different geometries. The fibrin clot growth results were compared to an experiment presented in literature. The biochemistry was found to be more sensitive to mesh size compared to the haemodynamics, while larger timesteps overpredicted clot size in pulsatile flow. When variable diffusivity was used, the predicted clot size was 25.4% lesser than that with constant diffusivity. The predicted clot size in pulsatile flow was 14.6% greater than in plug flow. Different vortex modes were observed in plug and pulsatile flow; the latter presented smaller intermediate modes where the main vortex was smaller and less likely to disrupt the growing fibrin clot. Furthermore, smaller vortex modes were seen to support fibrin clot propagation across geometries. The model clearly demonstrates how the growing fibrin clot alters vortical structures within the aneurysm sac and how this changing flow, in turn, shapes the growing fibrin clot.

Computational fluid dynamics for predicting the growth of small unruptured cerebral aneurysms.

OBJECTIVE: Larger cerebral aneurysms are more likely to enlarge, but even small aneurysms can grow. The aim of this study was to investigate the hemodynamic characteristics regarding the growth of small aneurysms using computational fluid dynamics (CFD). METHODS: The authors analyzed 185 patients with 215 unruptured cerebral aneurysms with a maximum diameter of 3-5 mm, registered in a multicenter prospective observational study of unruptured aneurysms (Systematic Multicenter Study of Unruptured Cerebral Aneurysms Based on Rheological Technique at Mie) from January 2013 to February 2022. Based on findings on repeated images, aneurysms were divided into a stable group (182 aneurysms) and a growth group (33 aneurysms). The authors developed the high shear concentration ratio (HSCR), in which high wall shear stress (HWSS) was defined as a value of 110% of the time-averaged wall shear stress of the dome. High shear area (HSA) was defined as the area with values above HWSS, and the ratio of the HSA to the surface area of the dome was defined as the HSA ratio (HSAR). They also created the flow concentration ratio (FCR) to measure the concentration of the inflow jet. Multivariate logistic regression analysis was performed to determine morphological variables and hemodynamic parameters that independently characterized the risk of growth. RESULTS: The growth group had a significantly higher projection ratio (0.74 vs 0.67, p = 0.04) and volume-to-ostium area ratio (1.72 vs 1.44, p = 0.02). Regarding the hemodynamic parameters, the growth group had significantly higher HSCR (6.39 vs 4.98, p < 0.001), lower HSAR (0.28 vs 0.33, p < 0.001), and lower FCR (0.61 vs 0.67, p = 0.005). In multivariate analyses, higher HSCR was significantly associated with growth (OR 0.81, 95% CI 7.06 e-1 to 9.36 e-1; p = 0.004). CONCLUSIONS: HSCR may be a useful hemodynamic parameter to predict the growth of small unruptured cerebral aneurysms.

Cerebrovascular Abnormalities in Adults Born SGA at 12 Years After Growth Hormone Cessation Compared to Controls.

CONTEXT: Increased cerebrovascular morbidity was reported in adults born small for gestational age (SGA) who were treated with growth hormone (GH) during childhood compared to the general population. However, previous studies did not have an appropriate control group, which is a major limitation. OBJECTIVE: To study cerebrovascular abnormalities (aneurysms, previous intracerebral hemorrhages and microbleeds) using magnetic resonance imaging (MRI) in adults born SGA at 12 years after cessation of childhood GH treatment (SGA-GH) compared to appropriate controls. METHODS: In this single-center, prospective study, brain MRIs were performed between May 2016 and December 2020 on a 3T MRI system. MRI images were scored by 2 neuroradiologists who were blinded to patient groupings. Participants included adults born SGA previously treated with GH and 3 untreated control groups: adults born SGA with persistent short stature (SGA-S), adults born SGA with spontaneous catch-up growth to a normal height (SGA-CU) and adults born appropriate for gestational age with a normal height (AGA). The intervention was long-term GH treatment during childhood and the main outcome measure was cerebrovascular abnormalities. RESULTS: A total of 301 adults were investigated. Aneurysms were found in 6 adults: 3 (3.6%) SGA-GH, 1 (2.9%) SGA-S and 2 (2.2%) AGA adults, without differences between SGA-GH adults and the controls. Previous intracerebral hemorrhages were only found in 2 SGA-S adults (4.8%). Microbleeds were found in 17 adults: 4 (4.3%) SGA-GH, 4 (9.5%) SGA-S, 3 (4.3%) SGA-CU and 6 (6.3%) AGA adults, without differences between SGA-GH adults and the controls. CONCLUSION: Our findings suggest that SGA-GH adults at 12 years after GH cessation have no increased prevalence of cerebrovascular abnormalities compared to appropriate controls. Further research is needed to confirm our findings.

A comprehensive simulation framework for predicting the eCLIPs implant crimping into a catheter and its deployment mechanisms.

Tubular flow diverters (FDs) represent an important subset of the endovascular treatment of cerebral aneurysms (CAs), acting to reduce aneurysm inflow, eventually resulting in aneurysm thrombosis and occlusion. eCLIPs (product of Evasc Neurovascular Enterprises, Vancouver, Canada), an innovative non-tubular implant causes flow diversion by bridging the neck of bifurcation CAs. However, in a small subset of challenging bifurcation aneurysms with fusiform pathology, the currently available eCLIPs models do not provide sufficient neck bridging resulting in a gap created between the device structure and the aneurysm/artery wall. To overcome this challenge, a new design of the eCLIPs (VR-eCLIPs) was developed by varying the rib length to cover such an inflow gap. To optimize the new product development process, and avoiding expensive and time-consuming iterative manufacture of prototype devices, we have developed a new finite element model to simulate the crimping and expansion processes of the VR-eCLIPs implant, and assess the possibility of plastic deformation. Results indicated that neither eCLIPs nor VR-eCLIPs experience plastic deformation during the crimping process. Upon full expansion, the ribs of VR-eCLIPs interact with the aneurysm and artery wall to cover the inflow gap that exists in certain challenging anatomies. This process serves as a basis to expedite design development prior to prototype manufacturing.