Search Results (322)

Background/Objectives: Posterior inferior cerebellar artery (PICA) aneurysms are one of the most difficult cerebrovascular lesions to treat and account for 0.5–3% of all intracranial aneurysms. They have deep anatomical locations, broad-neck configurations, high perforator density, and a close association with the brainstem, which creates considerable technical challenges for either microsurgical or endovascular treatment. Despite its acceptance as the standard of care for most posterior circulation aneurysms, PICA aneurysms are often associated with flow diversion using a coil or flow diversion due to incomplete occlusions, parent vessel compromise and high rate of recurrence. This case aims to describe the utility of microsurgical clipping as a durable and definitive option demonstrating the value of tailored surgical planning, preservation of anatomy and ancillary technologies for protecting a genuine outcome in ruptured PICA aneurysms. Methods: A 66-year-old male was evaluated for an acute subarachnoid hemorrhage from a ruptured and broad-necked fusiform left PICA aneurysm at the vertebra–PICA junction. Endovascular therapy was not an option due to morphology and the center of the recurrence; therefore, a microsurgical approach was essential. A far-lateral craniotomy with a partial C1 laminectomy was carried out for proximal vascular control, with careful dissection of the perforating arteries and precise clip application for the complete exclusion of the aneurysm whilst preserving distal PICA flow. Results: Post-operative imaging demonstrated the complete obliteration of the aneurysm with unchanged cerebrovascular flow dynamics. The patient had progressive neurological recovery with no new cranial nerve deficits or ischemic complications. Long-term follow-up demonstrated stable aneurysm exclusion and full functional independence emphasizing the sustainability of microsurgical intervention in challenging PICA aneurysms. Conclusions: This case intends to highlight the current and evolving role of microsurgical practice for treating posterior circulation aneurysms, particularly at a time when endovascular alternatives are limited by anatomy and hemodynamics. Advances in artificial intelligence cerebral aneurysm rupture prediction, high-resolution vessel wall imaging, robotic-assisted microsurgery and new generation flow-modifying implants have the potential to revolutionize treatment paradigms by embedding precision medicine principles into aneurysm management. While the discipline of cerebrovascular surgery is expanding, it can be combined together with microsurgery, endovascular technologies and computational knowledge to ensure individualized, durable, and minimally invasive treatment options for high-risk PICA aneurysms. Full article

Background: The anterior cerebral artery (ACA), a critical component of the cerebral arterial circle, exhibits substantial morphological variability. While previous studies have explored ACA morphology using cadaveric and imaging methods, a comprehensive meta-analysis incorporating the latest evidence is lacking. Methods: Following current guidelines, a systematic review and meta-analysis were performed across four major databases, supplemented by the gray literature and targeted journal searches. Ninety-nine studies, encompassing 85,316 patients, met the inclusion criteria. Statistical analyses were conducted using R, applying random effects models to estimate pooled prevalence and morphometric parameters. Results: The pooled prevalence of typical ACA morphology was 93.75%, whereas variants were noted in 6.25% of cases. The predominant variation identified was the accessory ACA (aACA) (1.99%), followed by unilateral absence of the A1 segment (1.78%), with the latter being more frequently recognized in imaging studies (p < 0.0001). Rare variants encompassed azygos ACA (azACA) (0.22%), fenestrated ACA (fACA) (0.02%), and bihemispheric ACA (bACA) (0.02%). The mean diameter and length of the A1 segment were measured at 2.10 mm and 14.24 mm, respectively. Hypoplasia of the A1 segment (<1 mm diameter) was recorded in 3.15% of cases. The influences of imaging modality, laterality, and population distribution on prevalence estimates were minimal. No significant publication bias was detected. Conclusions: Although infrequent, variants of the ACA possess significant clinical importance attributable to their correlation with aneurysm formation and the impairment of collateral circulation. The aACA and the absence of the A1 segment emerged as the most common variations. This meta-analysis presents an updated and high-quality synthesis of ACA morphology, serving as a valuable reference for clinicians and anatomists. Full article

Background/Objectives: A growing body of evidence is amassing in the literature suggesting a correlation between Alzheimer’s disease (AD) and thrombotic vascular complications, which led to the suggestive hypothesis that thrombosis may contribute to AD onset and progression by damaging the neurovasculature and reducing the cerebral blood flow. In turn, low cerebral blood flow is likely to contribute to neurodegeneration by reducing nutrient and oxygen supply and impairing toxic metabolite removal from the brain tissue. Methods: We searched the literature for studies in animal models of AD or patients diagnosed with the disease that reported circulating markers of platelet hyperactivity or hypercoagulation, or histological evidence of brain vascular thrombosis. Results: Platelet hyperactivity and hypercoagulability have been described in multiple animal models of AD, and histological evidence of neurovascular thrombosis has also been reported. Similarly, clinical studies on patients with AD showed circulating markers of platelet hyperactivity and hypercoagulation, or histological evidence of neurovascular thrombosis collected from post-mortem brain tissue samples. Conclusions: Taken together, a convincing picture is emerging that suggests a strong correlation between systemic or neurovascular thrombosis and AD. Nonetheless, a mechanistic role for haemostasis dysregulation and neurovascular damage in the onset or the progression of AD remains to be proven. Future research should focus on this important question in order to clarify the mechanisms underlying AD and identify a treatment for this disease. Full article

Background: Intercellular communication, facilitated by exosomes (Exos) derived from endothelial cells (ECs), significantly influences the regulation of angiogenesis. Leech extract significantly reduces ischemia–reperfusion injury, promotes angiogenesis, and improves neurological function in mice with stroke. However, further investigation is required to determine whether leech promotes angiogenesis through EC-Exo. Objective: This study aims to further explore whether leech regulates Exos to promote the establishment of collateral circulation in mice with ischemic stroke (IS) and the specific mechanisms involved. Methods: Here, we utilized an in vitro co-culture system comprising ECs and pericytes to investigate the impact of Leech-EC-Exo on enhancing the proliferation and migration of mouse brain microvascular pericytes (MBVPs). We further established an in vivo mouse model of middle cerebral artery occlusion/reperfusion (MCAO/R) to investigate the effects and underlying mechanisms of leech on collateral circulation establishment. Results: The findings demonstrated that leech significantly enhanced the in vitro cell migration number and migration number of pericytes. Therefore, it can also enhance the effect of EC-Exo on improving the infarct area and gait of mice, as well as modulating the HIFα-VEGF-DLL4-Notch1 signaling pathway to promote cerebral angiogenesis and facilitating the stable maturation of neovascularization in vivo. Conclusions: These results suggest that leech has the potential to enhance collateral circulation establishment, and its mechanism may involve the modulation of miRNA content in Exos and the promotion of signaling pathways associated with angiogenesis and vascular maturation. Full article

Aneurysmal subarachnoid hemorrhage (aSAH) has high morbidity and mortality in part due to vasospasm and delayed cerebral ischemia (DCI). This retrospective, single-center, case–control study evaluates the accuracy of an attention test, counting backwards from twenty to one (TTO), for detecting vasospasm and DCI in patients admitted to the ICU with aSAH over one year. The odds of symptomatic vasospasm and hospital outcomes were compared between the inattention and control groups. A subgroup analysis included accuracy tests comparing TTO to radiographic vasospasm. Of 44 subjects, 24 had inattention during their ICU course. Compared to controls, the inattention group had increased odds of vasospasm (OR 72 [7.6–677.7], p = 0.001), with significantly longer ICU (5.9 days) and hospital (6.6 days) lengths of stay, and higher odds of discharge to other healthcare facilities (OR 11.4 [2.8 to 46.8], p < 0.001). Errors on TTO testing had a specificity and sensitivity of 78%, and a positive predictive value (PPV) of 91%, for radiographic vasospasm, primarily in the anterior circulation. This study provides support for future prospective research to help elucidate the utility of TTO testing for monitoring and treatment of patients with aSAH. Full article

Background/Objectives: Fluid dynamic models of the cerebral vasculature are being developed to evaluate intracranial vascular pathology. Fluid–structure interaction modeling provides an opportunity for more accurate simulation of vascular pathology by modelling the vessel wall itself in conjunction with the fluid forces. Accuracy of these models is heavily dependent on the parameters used. Of those studied, elastin has been considered a key component used in aortic and common carotid artery modeling. We studied elastin thickness to determine if there was significant variation between cerebral artery territories to suggest its importance in cerebral blood vessel biomechanical response and provide reference data for modeling intracranial elastin. Elastin thickness was compared to vessel location, thickness, diameter, and laterality within human intracranial arteries. Methods: Tissue was taken from five human cadaveric heads preserved in formaldehyde from each intracranial vessel distribution bilaterally and stained with Van Gieson stain for elastin. A total of 160 normal cerebral vascular artery specimens were obtained from 17 different cerebrovascular regions. Two reviewers measured elastin thickness for each sample at five different locations per sample using Aperio ImageScope (Leica Biosystems, Deer Park, IL, USA). Statistical analysis of the samples was performed using mixed-models repeated measures regression methods. Results: There was a significant difference between anterior circulation (6.01 µm) and posterior circulation (4.4 µm) vessel elastin thickness (p-value < 0.05). Additionally, two predictive models of elastin thickness were presented, utilizing a combination of anterior versus posterior circulation, vessel diameter, and vessel wall thickness, which demonstrated significance for prediction with anterior versus posterior combined with vessel diameter and wall thickness. Conclusions: Elastin thicknesses are significantly different between anterior and posterior circulation vessels, which may explain the differences seen in aneurysm rupture risk for anterior versus posterior circulation aneurysms. Additionally, we propose two potential models for predicting elastin thickness based on vessel location, vessel diameter, and vessel wall thickness, all of which can be obtained using preoperative imaging techniques. These findings suggest that elastin plays an important role in cerebral vascular wall integrity, and this data will further enable fluid–structure interaction modeling parameters to be more precise in an effort to provide predictive modeling for cerebrovascular pathology. Full article

Aquaporins (AQPs) are a family of transmembrane water channel proteins facilitating the transport of water and, in some cases, small solutes such as glycerol, lactate, and urea. In the central nervous system (CNS), several aquaporins play crucial roles in maintaining water homeostasis, modulating cerebrospinal fluid (CSF) circulation, regulating energy metabolism, and facilitating neuroprotection under pathological conditions. Among them, AQP2, AQP4, AQP9, and AQP11 have been implicated in traumatic and non-traumatic brain injuries. The most abundant aquaporin (AQP) in the brain, AQP4, is essential for fluid regulation, facilitating water transport across the blood–brain barrier and glymphatic clearance. AQP2 is primarily known for its function in the kidneys, but it is also expressed in brain regions related to vasopressin signaling and CSF dynamics. AQP9 acts as a channel for glycerol and lactate, thus playing a role in metabolic adaptation during brain injury. AQP11, an intracellular aquaporin, is involved in oxidative stress responses and cellular homeostasis, with emerging evidence suggesting its role in neuroprotection. Aquaporins play a dual role in brain injury; while they help maintain homeostasis, their dysregulation can exacerbate cerebral edema, metabolic dysfunction, and inflammation. In traumatic brain injury (TBI), aquaporins regulate the formation and resolution of cerebral edema. In non-traumatic brain injuries, including ischemic stroke, aneurysmal subarachnoid hemorrhage (aSAH), and intracerebral hemorrhage (ICH), aquaporins influence fluid balance, energy metabolism, and oxidative stress responses. Understanding the specific roles of AQP2, AQP4, AQP9, and AQP11 in these brain injuries may lead to new therapeutic strategies to mitigate secondary damage and improve neurological outcomes. This review explores the function of the above aquaporins in both traumatic and non-traumatic brain injuries, highlighting their potential and limitations as therapeutic targets for neuroprotection and recovery. Full article

Background/Objectives: Near-infrared spectroscopy (NIRS) enables the non-invasive assessment of cerebral oximetry, offering insights into the efficacy of oxygen supply to the brain. NIRS, when combined with other monitoring techniques such as capnography, may play a crucial role in advanced patient monitoring during sudden cardiac arrest and post-resuscitation treatment. This research assessed the relationship between end-tidal carbon dioxide (ETCO₂) and regional cerebral oxygen saturation (rSO₂) during cardiopulmonary resuscitation. Methods: The research was performed from 11 January 2023 until 31 January 2024, at the University Hospital in Poland. The cohort of responders included patients who had in-hospital cardiac arrest (IHCA). The Rapid Response Team attached the rSO₂ and ETCO₂ monitoring devices to each patient during cardiopulmonary resuscitation (CPR). The cohort included 104 patients. Results: The correlation coefficient between ETCO₂ and rSO₂ values was 0.641 (95% CI: 0.636–0.646), and during the last 4 min of CPR before ROSC, it was 0.873 (95% CI: 0.824–0.910). Conclusions: The positive correlation between ETCO₂ and rSO₂ may suggest that concurrent monitoring of both parameters during resuscitation might serve as a valuable predictor of CPR efficacy and the likelihood of achieving recovery of spontaneous circulation in a multimodal framework. In the lack of rapid ETCO₂ monitoring capabilities, rSO₂ may function as a simple and effective alternative for assessment. Full article

We present a rare case of a 16-year-old male who was admitted with bilateral tinnitus and subsequently underwent magnetic resonance imaging (MRI) and digital subtraction angiography (DSA) for further evaluation. The left internal carotid (ICA) artery had a normal caliber but ended as a stump at the C7 segment, with a network of filiform vessels from both the stump and right posterior communicating artery (PComm). The right PComm was hypertrophic and the right posterior cerebral artery (PCA) was mainly supplied by the right ICA. The right ICA’s bifurcation and the initial middle cerebral artery (MCA) segment were absent, while the MCA trunk was hypoplastic. The right PCA and pial branches vascularized the temporal lobe, with collaterals between the PCA and MCA. The left ICA was slightly enlarged with double fenestration at the left A1 segment. The right A1 segment of the anterior cerebral artery had double fenestration and while several diagnoses were considered, no single diagnosis fully explained all clinical findings. A thorough review of the existing literature yielded no comparable cases, highlighting the uniqueness of this presentation. This case emphasizes the complexity of cerebral vascular anomalies and the challenges associated with diagnosing such rare conditions, underscoring the need for careful assessment. Full article

Increases in flow elicit dilations in the basilar artery (BA) supplied by the posterior cerebral circulation (PCC), and ensuring efficient blood supply to the circle of Willis in which blood flow and pressure can distribute and equalize, and thus provide the appropriate supply for the daughter branches to reach certain brain areas. In contrast, increases in flow elicit constrictions in the middle cerebral artery (MCA), supplied by the anterior cerebral circulation (ACC) and regulating the blood pressure and flow in distal cerebral circulation. Mediators of flow-dependent responses include arachidonic acid (AA) metabolites and nitric oxide (NO). We hypothesized that mediators of flow-dependent responses are differentially expressed in cerebral arteries of the PCC (CA_PCC) and ACC (CA_ACC). The expressions of key enzymes of the AA pathway—cyclooxygenases (COX1/COX2), cytochrome P450 hydroxylases (Cyp450), thromboxane synthase (TXAS), thromboxane A2 (TP) receptor, prostacyclin synthase (PGIS), prostacyclin (IP) receptor (IP); neuronal nitric oxide synthase (nNOS), and endothelial nitric oxide synthase (eNOS)—in the BA and MCA from rats (n = 20) were determined by western blotting. Transcriptome analysis in CA_PCC and CA_ACC from rats (n = 25) was assessed by RNA sequencing. In BA compared to MCA, COX1/2 and Cyp450 protein expressions were lower, PGIS was higher, TXAS and nNOS/eNOS were similar, TP receptors were lower, and IP receptors were higher. Gene expressions of vasodilator canonical pathways were higher in CA_PCC; vasoconstriction canonical pathways were higher in CA_ACC. Mediators of flow-dependent vasomotor signaling are differentially expressed in cerebral arteries of the posterior and anterior circulation, corresponding to their vasomotor function. Full article

Background and Clinical Significance: Carotid stump syndrome (CSS) is a rare and unexpected cause of recurrent ischemic ipsilateral events in the carotid vascular territory despite the demonstrated occlusion of the internal carotid artery (ICA). It is believed to be caused by microemboli due to turbulent blood flow in the patent stump of the occluded ICA that passes through anastomotic channels and retrograde flow into the middle cerebral artery circulation. Case Presentation: We describe the case of a 65-year-old male patient who suffered multiple concurrent transient ischemic attacks (TIAs) with a totally occluded ipsilateral ICA revealed by computed tomography angiography (CTA). He was diagnosed with CSS, which required the safest therapeutic approach. A further investigation with digital subtraction angiography (DSA) was performed, and a trickle of blood flow was observed in the reportedly occluded ICA. The diagnosis of a true ICA occlusion was withdrawn, and a diagnosis of pseudo-occlusion was established, affecting the final treatment strategy. Therefore, the patient underwent an ipsilateral carotid endarterectomy (CEA), and he has remained asymptomatic since then. Conclusions: The differentiation between a pseudo-occlusion and a true ICA occlusion is essential in promptly managing acute recurrent ipsilateral ischemic strokes in the carotid vascular territory. A further investigation with DSA in cases with a totally occluded ICA using CTA is essential for excluding pseudo-occlusions in ipsilaterally symptomatic patients. Full article

Background: Primary cardiac tumors (PCTs) are rare entities, with only a minority being malignant and capable of distant dissemination. Among the rarest and most challenging metastatic events are brain metastases originating from cardiac tumors. Due to the heart’s direct access to systemic circulation, even benign tumors such as atrial myxomas may cause cerebral embolic phenomena. Understanding the distinct biological behavior, diagnostic pathways, therapeutic strategies, and prognostic implications of these cases remains limited by the scarcity of the available literature. Methods: A systematic review was conducted following PRISMA guidelines. PubMed, Scopus, Embase, and other major databases were systematically searched using specific MeSH terms and keywords related to cardiac tumors and brain metastases. After applying strict inclusion and exclusion criteria, nineteen studies were included, comprising sixteen single-patient case reports and three multi-patient series. Extracted data included tumor histology, cardiac and brain imaging findings, neurological presentation, treatment approaches, and patient outcomes. Results: A total of 320 patients were analyzed. Atrial myxomas represented the predominant benign tumors causing embolic cerebral events, while angiosarcomas and other cardiac sarcomas were responsible for true hematogenous brain metastases. Brain involvement was frequently hemorrhagic and manifested with seizures, focal deficits, or signs of intracranial hypertension. Cardiac echocardiography and cardiac magnetic resonance imaging (CMR) were essential for tumor detection, while brain MRI, including SWI and DWI sequences, and CT scanning were critical for cerebral lesion characterization. Treatment strategies varied according to tumor type and included surgery, radiotherapy, and systemic therapies. Malignant cardiac tumors correlated with a poor prognosis, with median survival post-CNS involvement ranging from 12 to 14 months. Conclusions: Brain metastases from PCTs, though rare, represent a distinct and serious clinical phenomenon. Benign tumors like myxomas mainly cause embolic cerebral events, whereas malignant tumors, particularly sarcomas, lead to true metastatic brain lesions. Recognizing this biological distinction is crucial for diagnosis, prognostication, and therapeutic planning. An integrated multidisciplinary approach combining advanced cardiac and neuroimaging techniques is vital for early detection and appropriate management. Despite multimodal treatment, survival remains limited, underscoring the urgent need for novel targeted therapies and improved surveillance strategies. Full article

Background. Statins appear to be useful in patients with acute ischemic stroke. Our aim was to evaluate the association between premorbid statin treatment and CT perfusion characteristics of acute ischemic stroke. Methods. A retrospective analysis of patients with acute stroke secondary to occlusion of large vessels in the anterior circulation was performed to assess collateral flow, ischemic core volume, and ischemic penumbra using CT angiography and CT perfusion maps. Fisher’s exact test was used to compare baseline characteristics of patients in the two groups. The Wilcoxon rank-sum test for independent groups was used to compare all variables obtained for the two different groups with and without statin use. Results. We identified 61 patients, including 29 treated with statins and 32 not treated with statins before stroke onset matched by age, gender, and vascular risk factors except for hypercholesterolemia. The statin group showed lower National Institutes of health Stroke Scale scores at onset (14 ± 6.1 vs. 16 ± 4.5; p = 0.04) and lower volumes of brain tissue characterized by impaired cerebral blood flow (CBF), cerebral blood volume (CBV), and ${\mathrm{T}}_{\mathrm{m}\mathrm{a}\mathrm{x}}^{9.5-25\mathrm{s}}$; otherwise, no statistically significant difference was found in the volume of the ${\mathrm{T}}_{\mathrm{m}\mathrm{a}\mathrm{x}}^{16-25\mathrm{s}}$ between the two groups. Conclusions. Premorbid statin treatment is associated with a favorable imaging condition of acute ischemic stroke in terms of ischemic core and ischemic penumbra volume. Full article

Objective: Cerebral vascularization is made of the symmetrical arterial system, with muscular walls, and the venous system, more variable and dominated by sinuses and jugular veins. Factors like age and posture influence this network, complicating its study. Phase-contrast MRI is the gold standard for quantifying cerebral circulation. This study aimed to quantify the dynamics of the cerebral blood system using PC-MRI. Materials and Methods: Thirty-six healthy adults participated. Imaging was performed on a 3T MRI (Philips Achieva) in a supine position. Two slices were acquired: intracranial and extracranial. In-house software analyzed flow curves over a cardiac cycle. Each vessel’s contribution was evaluated. Results: Extracranial venous drainage was categorized as jugular-dominant, equivalent, or peripheral-dominant. A similar classification applied intracranially. Intracranial flows showed low variability (5–9%), while extracranial venous flows, especially in the internal jugular veins, had higher variability (17–21%). Some extracranial veins were absent. Conclusions: There is significant venous heterogeneity in the extracranial region. PC-MRI enables the quantification of cerebral dynamics. Full article

Background: Endovascular mechanical thrombectomy (EVT) is regarded as the standard treatment for acute ischemic stroke with large vessel occlusion. Few studies have examined the evolution of cerebral flow after the acute stage of ischemic stroke. In this study, we examined the association of functional outcomes with cerebral blood flow by extracranial carotid sonography during the subacute phase after EVT and multiple prognostic variables. Methods: We conducted a single-center, retrospective, observational study between January 2018 and June 2023. Patients with acute stroke resulting from anterior circulation large vessel occlusion who underwent EVT were included. All patients underwent carotid sonography in the second week after EVT. Patients with fair (modified Rankin Scale [mRS]: 0–3) and poor outcomes (mRS: 4–6) were compared to determine the association between and identify the predictors of these factors and functional outcomes. Results: A total of 89 patients were included (female: 38 (42.7%); mean age: 69.45 ± 13.59 years). Multivariable logistic regression analysis revealed that three factors were independent predictors of fair outcomes: (1) the Alberta Stroke Program Early CT Score (odds ratio [OR]: 1.79; 95% confidence interval [CI]: 1.16–2.78; p = 0.009); (2) Thrombolysis in Cerebral Infarction 2b to 3 (OR: 4.91; 95%CI: 1.10–21.89; p = 0.037); (3) the ratio of treatment-side blood flow between the internal carotid artery and common carotid artery (QTI/QTC, OR: 45.35; 95% CI: 1.11–1847.51; p = 0.04). Conclusions: The ratio of QTI/QTC is a clinically relevant parameter as a potential predictor of favorable outcomes. This parameter can be used to formulate patient prognostic scores and help clinicians determine whether adequate cerebral perfusion is maintained during the subacute phase. Full article