Hui, Ferdinand

Background The eccentric stenosis morphology in patients with intracranial atherosclerotic stenosis (ICAS) has a critical impact on the efficacy of endovascular treatment. This study aimed to establish a rabbit model of eccentric carotid atherosclerotic stenosis that mimics the pathophysiological and morphological characteristics of eccentric plaques in humans. Methods Rabbits received localized cryoinjury of the right carotid artery after 2 weeks of a high fat, high cholesterol diet, followed by an additional 8 weeks on the same diet. On the experimental endpoint, comprehensive analyses of the model’s pathological changes were conducted using serum lipid analysis, DSA, optical coherence tomography (OCT), histopathological analysis, and immunohistochemistry. Results The high fat, high cholesterol diet significantly elevated serum lipid levels in rabbits. Hematoxylin and eosin staining results at 24 hours postoperatively revealed focal intimal damage induced by 5 s of cryoinjury. After localized cryoinjury and high fat, high cholesterol diet feeding, DSA results demonstrated significant carotid stenosis, with a stenosis degree of 47±5% and a length of approximately 9 mm. OCT images revealed eccentric fibrous plaque formation at the stenotic site. Morphological analysis of the plaque samples demonstrated a plaque eccentricity index of 0.66±0.05 and a plaque burden of 60.68±7.41%. Histopathological analysis showed that atherosclerotic lesions developed in all rabbits of the model group. Among them, three rabbits had intermediate lesions, one rabbit had atheroma, and eight rabbits had fibroatheroma. Conclusions This study successfully established a rabbit model of eccentric carotid atherosclerotic stenosis, providing a novel experimental platform for transformation research of neurointerventional devices.

Objective Cognitive impairment is increasingly recognized in patients with cerebral venous congestion (CVC), yet the cognitive tools used are largely adapted from stroke and dementia research. This review examines current literature on cognitive function in CVC, including conditions such as cerebral venous sinus thrombosis (CVST), idiopathic intracranial hypertension (IIH), and dural arteriovenous fistulas (dAVFs). Special emphasis is placed on the limitations of common screening tools like the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE). Cognitive dysfunction—primarily affecting executive function, processing speed, and attention—is reported in up to 86% of CVC cases, yet only about 20% of studies use validated cognitive testing tools, most of which may lack sensitivity for CVC-specific deficits. Emerging techniques such as ocular motor testing and physiological markers show promise but require further validation. There is an urgent need for standardized, CVC-specific cognitive assessment protocols that reflect the unique pathophysiology of venous disorders. Future research should prioritize the development of targeted cognitive batteries and integrate objective physiological measures to enhance diagnostic accuracy.

Background Nickel hypersensitivity is the most common metal related allergy. Nickel containing alloys are frequently used in endovascular devices. The use of intracranial stents in patients with nickel hypersensitivity appears to be safe, but these small series only evaluated arterial stent placement. This case series aimed to assess the safety of intracranial venous stent placement in patients with documented nickel allergy. Methods In this retrospective multicenter case series, patients with idiopathic intracranial hypertension and documented nickel allergy underwent treatment with a permanently implanted nickel containing stent in the dural venous sinuses. Results Nine patients with nickel allergy were included. All patients reported clinical improvement in their idiopathic intracranial hypertension symptoms. Of the five patients who had follow-up intracranial venous imaging, all stents remained patent. No patients experienced intraoperative, postoperative, or long term procedure related complications, with follow-up ranging from 1.8 weeks to 49.1 months. Conclusion In this limited case series, the use of nickel containing stents in intracranial venous sinuses in patients with nickel allergy did not result in any allergic reaction or adverse outcome.

Background The recognition of venous sinus stenosis as a contributing factor in the majority of patients with idiopathic intracranial hypertension coupled with increasing cerebral venography and venous sinus stenting experience have dramatically improved our understanding of the pathophysiologic mechanisms driving this disease. There is now a dense, growing body of research in the neurointerventional literature detailing anatomical and physiological mechanisms of disease which has not been widely disseminated among clinicians. Methods A literature search was conducted, covering the most recent neurointerventional literature on idiopathic intracranial hypertension, the pathophysiology of idiopathic intracranial hypertension, and management strategies (including venous sinus stenting), and subsequently summarized to provide a comprehensive review of the most recently published studies on idiopathic intracranial hypertension pathophysiology and management. Conclusion Recent studies in the neurointerventional literature have greatly improved our understanding of the pathophysiologic mechanisms causing idiopathic intracranial hypertension and its associated conditions. The ability to make individualized, patient-specific treatment approaches has been made possible by advances in our understanding of how venous sinus stenosis and cerebral venous hypertension fundamentally contribute to idiopathic intracranial hypertension.

BACKGROUND: Several collateral venous pathways exist to assist in cranial venous drainage in addition to the internal jugular veins. The important extrajugular networks (EJN) are often readily identified on diagnostic cerebral angiography. However, the angiographic pattern of venous drainage through collateral EJN has not been previously compared among patients with and without idiopathic intracranial hypertension (IIH). OBJECTIVE: To quantify EJN on cerebral angiography among patients both with and without IIH and to determine whether there is a different EJN venous drainage pattern in patients with IIH. METHODS: Retrospective imaging review of 100 cerebral angiograms (50 IIH and 50 non-IIH patients) and medical records from a single academic medical center was performed by 2 independent experienced neuroendovascular surgeons. Points were assigned to EJN flow from 0 to 6 using an increasing scale (with each patient's dominant internal jugular vein standardized to 5 points to serve as the internal reference). Angiography of each patient included 11 separately graded extrajugular networks for internal carotid and vertebral artery injections. RESULTS: Patients in the IIH group had statistically significant greater flow in several of the extrajugular networks. Therefore, they preferentially drained through EJN compared with the non-IIH group. Right transverse-sigmoid system was most often dominant in both groups, yet there was a significantly greater prevalence of codominant sinus pattern on posterior circulation angiograms. CONCLUSION: Patients with IIH have greater utilization of EJN compared with patients without IIH. Whether this is merely an epiphenomenon or possesses actual cause-effect relationships needs to be determined with further studies.

Background and Purpose: The HydroSoft coil was developed to be placed along the aneurysm neck to enhance intracranial aneurysm healing. In order to better understand the safety and efficacy of Hydrosoft coils in treating the aneurysm neck, the GEL THE NEC multicenter registry was developed. We report immediate angiographic and clinical results of this prospective registry. Methods: The GEL THE NEC study was undertaken at 30 centers in 5 countries. Patients aged 21-90 years with a ruptured or unruptured aneurysm 3-15 mm in size were eligible for enrollment. For each patient the following data were obtained: demographics and comorbidities, aneurysm geometry, use of adjunctive devices, immediate angiographic outcomes, and early (<30 days) adverse events. Postoperative anatomic results were graded by on-site neuroradiologists using the Modified Raymond Scale (Raymond 1=complete obliteration of aneurysm including the neck, Raymond 2=contrast filling the neck of the aneurysm without opacification of the aneurysm sac, Raymond 3=contrast filling the sac of the aneurysm). Predictors of good angiographic outcome were studied using chi-squared and t-tests. Results: A total of 571 patients with 571 aneurysms have been treated thus far in the study (196 ruptured, 375 unruptured). HydroSoft coils were successfully deployed in 549 (96.3%) of these patients. Adjunctive devices were used in 307 cases (53.8%) (212 balloon assistance, 89 stent). Aneurysmal occlusion rates were the following: 261 patients (47.3%) exhibited Raymond 1 occlusion, 257 patients (47.0%) had Raymond 2, and 29 patients (5.3%) had Raymond 3. Early post-operative stroke occurred in 10 patients (1.8%). Aneurysm perforation occurred in 11 patients (1.9%). Coil prolapse/migration occurred in 8 patients (1.4%). Early post-operative death occurred in 3 patients, all of whom presented with SAH (0.5%). Small aneurysm neck size was a significant predictor of good angiographic outcome (P=0.0003). Conclusions: Endovascular treatment of intracranial aneurysms with HydroSoft coils resulted in high rates of satisfactory occlusion (94.3%) and low rates of major clinical complications. Aneurysm neck size was a significant predictor of angiographic outcomes.

Purpose: Various imaging approaches are utilized for evaluating acute stroke patients. Despite numerous studies, there is no clear evidence that one approach is superior to another for identifying which patients will benefit from mechanical thrombectomy (MT). The PICS registry was established to determine the imaging modalities being employed to triage acute stroke patients for MT and to assess their impact on patient functional outcome. Methods: Patients were enrolled across 35 centers. For each patient, the baseline imaging modality was recorded to determine the utilization rates of noncontrast CT (NCCT), CT perfusion (CT-P), and MRI diffusion weighted imaging (DWI). All patients subsequently treated by the Penumbra System per standard of care were followed for 3 months after the procedure to assess functional outcome using the modified Rankin Scale (mRS). Results: A total of 305 patients were enrolled in this registry, of which 267 had the requisite imaging modalities used for this analysis. Of these, 49.4% were females. Mean age was 66.6 ± 15.9 years; median NIHSS score was 17.0 (IQR 12-21). The median time from stroke onset to presentation was 2.3 hours, from stroke symptom onset to arterial puncture was 4.8 hours, and from arterial puncture to end of thromboaspiration was 73.0 minutes. Post-treatment evaluation revealed that 83.5% of patients were successfully recanalized to TIMI 2/3 (from TIMI 0/1) with 43.5% achieving a 90-day mRS of 0-2. All cause mortality was 19.9% with symptomatic intracranial hemorrhage reported in 4.5% of the patients. The principal imaging modalities used for patient triage were NCCT in 61.8%, CT-P in 27.3% and DWI in 10.9% of the study population. Of the patients selected for NCCT, 42.5% were functionally independent at 90 days, whereas for CT-P and DWI, the rates were 45.9% and 42.9%, respectively. There was no significant difference between groups for patient age, baseline NIHSS, time from onset to presentation, time from arterial puncture to end of thromboaspiration. The time from stroke symptom onset to groin puncture was significantly different in the DWI cohort (p<0.0001) with a median of 4.4 hrs for NCCT, 4.8 hrs for CTP, and 6.5 hrs for DWI. There was a significant difference in % of female patients with CTP 37.0%, DWI 48.3%, and NCCT 55.2% (p=0.034). Conclusion: The type of imaging modality utilized to triage acute ischemic stroke patients for MT varies widely across the US. Based on the present findings, the imaging approach appears to have little impact on patient functional outcome after MT.

Abstract In children with arterial ischemic stroke (AIS), the definitive diagnosis of stroke subtype and confirmation of stroke etiology is necessary to mitigate stroke morbidity and prevent recurrent stroke. The common causes of AIS in children are sharply differentiated from the common causes of adult AIS. A comprehensive, structured diagnostic approach will identify the etiology of stroke in most children. Adequate diagnostic evaluation relies on advanced brain imaging and vascular imaging studies. A variety of medical and surgical secondary stroke prevention strategies directed at the underlying cause of stroke are available. This review aims to outline strategies for definitive diagnosis and secondary stroke prevention in children with AIS, emphasizing the critical role of neuroimaging.