Structural and Functional Imaging of the Retina in Central Retinal Artery Occlusion - Current Approaches and Future Directions.

Central retinal artery occlusion (CRAO) is a form of acute ischemic stroke which affects the retina. Intravenous thrombolysis is emerging as a compelling therapeutic approach. However, it is not known which patients may benefit from this therapy because there are no imaging modalities that adequately distinguish viable retina from irreversibly infarcted retina. The inner retina receives arterial supply from the central retinal artery and there is robust collateralization between this circulation and the outer retinal circulation, provided by the posterior ciliary circulation. Fundus photography can show canonical changes associated with CRAO including a cherry-red spot, arteriolar boxcarring and retinal pallor. Fluorescein angiography provides 2-dimensional imaging of the retinal circulation and can distinguish a complete from a partial CRAO as well as central versus peripheral retinal non-perfusion. Transorbital ultrasonography may assay flow through the central retinal artery and is useful in the exclusion of other orbital pathology that can mimic CRAO. Optical coherence tomography provides structural information on the different layers of the retina and exploratory work has described its utility in determining the time since onset of ischemia. Two experimental techniques are discussed. 1) Retinal functional imaging permits generation of capillary perfusion maps and can assay retinal oxygenation and blood flow velocity. 2) Photoacoustic imaging combines the principles of optical excitation and ultrasonic detection and - in animal studies - has been used to determine the retinal oxygen metabolic rate. Future techniques to determine retinal viability in clinical practice will require rapid, easily used, and reproducible methods that can be deployed in the emergency setting.

Routine 24-Hour Computed Tomography Brain Scan is not useful in stable patients Post Intravenous Tissue Plasminogen Activator.

BACKGROUND: Obtaining a routine computed tomography (CT) brain scan 24 hours after treatment with intravenous tissue plasminogen activator (IV-tPA) is included in the American Heart Association/American Stroke Association acute stroke guidelines. The usefulness of the test in stable patients is not known. We hypothesized that the results of routine, 24-hour post-treatment neuroimaging (CT or magnetic resonance imaging [MRI] brain scans) would not alter the management of clinically stable patients. METHODS: Patients treated with IV-tPA between January 2011 and December 2013 were identified from a single hospital's stroke registry. All patients were closely monitored for changes in stroke severity. Demographics, changes in neurological status, neuroimaging results, and changes in therapy were abstracted from the patients' medical records. Patients having a neuroimaging study because of neurological deterioration were excluded. RESULTS: Of 136 patients treated with IV-tPA, 131 met criteria for inclusion. Of these, 86.7% had moderate to severe neurological deficits (i.e., initial National Institutes of Health Stroke Scale score > 5 points; median 8 points). All patients had routine imaging ~24 hours after treatment (CT brain 62.6%, MRI brain 12.4%, both CT and MRI brain 25%). Asymptomatic hemorrhagic transformation occurred in 6.7% and potentially changed management in a single patient (target systolic blood pressure was lowered from 185 to 180 mmHg). CONCLUSIONS: Over a 3-year period, routine neuroimaging ~24-hours after IV-tPA in clinically stable patients was associated with a change in therapy in only 1 (.95%) patient. If confirmed in other cohorts, these results suggest that routine neuroimaging after IV-tPA may be safely avoided in clinically stable patients, eliminating unnecessary radiation exposure in those having CT brain and reducing costs.

Assessment of healthcare personnel knowledge of stroke care at a large referral hospital in sub-Saharan Africa - A survey based approach.

There is no published literature regarding sub-Saharan health-care providers' understanding of stroke management patterns. Understanding current stroke management knowledge is important in formulating future education opportunities for providers to optimize patient outcomes. A cross-sectional survey of acute stroke diagnosis, hospital management, and secondary prevention questions was administered to health-care providers working in one large Kenyan acute referral hospital. Due to the prevalence of medical students (61.8%), an experienced-focused analysis contrasted students with more experienced providers. Providers (n=199) anonymously responded to the surveys. Among the acute diagnosis most respondents stated that stroke scales should always used (58.3% of respondents), 3h was the time period for alteplase (t-PA) (53.8% of respondents), and CT scan should be always be obtained prior to administration of anticoagulant therapy (61.3% of respondents). Neither VTE prophylaxis nor dysphagia/swallowing screening were considered to be done a majority of time. Secondary prevention results were variable. The respondent's level of clinical experience made the most difference in correctly answering the most appropriate IV Fluid to use in stroke patients (adjusted p=0.003) and the ideal initiation time for antithrombotic therapy (adjusted p=0.0017). Healthcare providers demonstrated a wide variability in their responses. Future efforts to improve stroke care in sub-Saharan Africa should include education and process improvement initiatives to focus on more specific aspects of stroke management based on the results from this survey.