Cerebral collateral circulation is a network of blood vessels which stabilizes blood flow and maintains cerebral perfusion whenever the main arteries fail to provide an adequate blood supply, as happens in ischemic stroke. These arterial networks are able to divert blood flow to hypoperfused cerebral areas. The extent of the collateral circulation determines the volume of the salvageable tissue, the so-called “penumbra”. Clinically, this is associated with greater efficacy of reperfusion therapies (thrombolysis and thrombectomy) in terms of better short- and long-term functional outcomes, lower incidence of hemorrhagic transformation and of malignant oedema, and smaller cerebral infarctions. Recent advancements in brain imaging techniques (CT and MRI) allow us to study these anastomotic networks in detail and increase the likelihood of making effective therapeutic choices. In this narrative review we will investigate the pathophysiology, the clinical aspects, and the possible diagnostic and therapeutic role of collateral circulation in acute ischemic stroke.

Spinal cord infarction (SCI) of arterial origin is a rare vascular event, and its incidence is probably underestimated. There are no strong epidemiological data, and the diagnostic pathway is complex and sometimes incomplete. Furthermore, many cases may be misdiagnosed as other forms of acute and subacute myelopathies. The focus of this review is the clinical and neuroradiological issues in diagnosing SCI and their respective reliability in a clinical setting. The new proposed diagnostic criteria of SCI, although not covering all aspects, highlight the need for a comprehensive approach, including even atypical cases, as the lack of cord compression on Magnetic Resonance Imaging (MRI) is the only mandatory feature for diagnosis. Some MRI features are supportive of the diagnosis, particularly when the anterior spinal artery territory is involved and diffusion-weighted imaging (DWI) is used. Several etiologies can be considered, considering traditional vascular risk factors and diseases affecting the aorta and its main branches, yet a significant proportion of cases remain without a definite etiology. The strongest predictor of SCI diagnosis is a clinical variable, i.e., a time to nadir of severe deficits < 12 h.

Introduction: Inequity in stroke care in Europe has previously been reported despite the existence of evidence-based cost-effective interventions for both prevention and treatment. This report aims to provide comprehensive data on stroke care in Europe in 2023 and explore associations to European regions, organisational and economic factors. Patients and methods: The Stroke Service Tracker, an annually collected survey-based dataset of aggregate summary data from participating European nations, was used with key performance indicators (KPIs) from the Stroke Action Plan for Europe (SAP-E). European regions were defined based on United Nations Geoscheme regions. Gross domestic product (GDP) per capita and healthcare spending per capita were collected based on World Bank data. Results: A total of 1,460,630 stroke events were reported in 2023 from 52 nations. Significant inequity was present in all data points and data quality varied significantly. Twenty (43.5%) nations have a national stroke plan in place, and in 19 (41.3%) work is ongoing. Quality programmes have been implemented in 20 (43.5%) nations. Implementation of a national stroke plan or a quality programme was associated with achieving more SAP-E KPIs (P < .001). There were regional differences in the number of met KPIs (P < .001). Both GDP and healthcare spending per capita were strongly correlated to meeting KPIs. Conclusion: The inequity in stroke care persists in Europe. Implementation of a national stroke plan and a quality programme is associated with meeting more KPIs; however, economic factors may pose limitations. Access to high-quality data will support decision-making towards evidence-based and cost-effective care.

Spontaneous convexity subarachnoid hemorrhage (cSAH) is a vascular disease different from aneurysmal SAH in neuroimaging pattern, causes, and prognosis. Several causes might be considered in individual patients, with a limited value of the patient’s age for discriminating among these causes. Cerebral amyloid angiopathy (CAA) is the most prevalent cause in people > 60 years, but reversible cerebral vasoconstriction syndrome (RCVS) has to be considered in young people. CAA gained attention in the last years, but the most known manifestation of cSAH in this context is constituted by transient focal neurological episodes (TFNEs). CAA might have an inflammatory side (CAA-related inflammation), whose diagnosis is relevant due to the efficacy of immunosuppression in resolving essudation. Other causes are hemodynamic stenosis or occlusion in extracranial and intracranial arteries, infective endocarditis (with or without intracranial infectious aneurysms), primary central nervous system angiitis, cerebral venous thrombosis, and rarer diseases. The diagnostic work-up is fundamental for an etiological diagnosis and includes neuroimaging techniques, nuclear medicine techniques, and lumbar puncture. The correct diagnosis is the first step for choosing the most effective and appropriate treatment.

The anterior choroidal artery (AChA) originates from the posterior wall of the internal carotid distal to the posterior communicating artery and proximal to the intracerebral carotid bifurcation. This thin artery is rarely the cause of aneurysm and only accounts for 2-5% of all aneurysms. Even though the AChA territory shows large variations among individuals, it supplies crucial motor and sensory structures, such as the internal capsule, optic tract, the posterior limb of the internal capsule, the cerebral peduncle, and the choroid plexus.