May Nour

Ischemia-Reperfusion Injury in Stroke

Despite ongoing advances in stroke imaging and treatment, ischemic and hemorrhagic stroke continue to debilitate patients with devastating outcomes at both the personal and societal levels. While the ultimate goal of therapy in ischemic stroke is geared towards restoration of blood flow, even when mitigation of initial tissue hypoxia is successful, exacerbation of tissue injury may occur in the form of cell death, or alternatively, hemorrhagic transformation of reperfused tissue. Animal models have extensively demonstrated the concept of reperfusion injury at the molecular and cellular levels, yet no study has quantified this effect in stroke patients. These preclinical models have also demonstrated the success of a wide array of neuroprotective strategies at lessening the deleterious effects of reperfusion injury. Serial multimodal imaging may provide a framework for developing therapies for reperfusion injury.

Data science of stroke imaging and enlightenment of the penumbra

Imaging protocols of acute ischemic stroke continue to hold significant uncertainties regarding patient selection for reperfusion therapy with thrombolysis and mechanical thrombectomy. Given that patient inclusion criteria can easily introduce biases that may be unaccounted for, the reproducibility and reliability of the patient screening method is of utmost importance in clinical trial design. The optimal imaging screening protocol for selection in targeted populations remains uncertain. Acute neuroimaging provides a snapshot in time of the brain parenchyma and vasculature. By identifying the at-risk but still viable penumbral tissue, imaging can help estimate the potential benefit of a reperfusion therapy in these patients. This paper provides a perspective about the assessment of the penumbral tissue in the context of acute stroke and reviews several neuroimaging models that have recently been developed to assess the penumbra in a more reliable fashion. The complexity and variability of imaging features and techniques used in stroke will ultimately require advanced data driven software tools to provide quantitative measures of risk/benefit of recanalization therapy and help aid in making the most favorable clinical decisions.

Brain Imaging in Stroke: Insight Beyond Diagnosis

Stroke, whether hemorrhagic or ischemic in nature, has the ability to lead to devastating and debilitating patient outcomes, which not only has direct implications from a healthcare standpoint, but its effects are longstanding and they impact the community as a whole. For decades, the goal of advancement and refinement in imaging modalities has been to develop the most precise, convenient, widely available and reproducible interpretable modality for the detection of stroke, not only in its hyperacute phase, but a method to be able to predict its evolution through the natural course of disease. Diagnosis is one of the most important initial roles, which imaging fulfills after the identification of existent pathology. However, imaging fulfills an even more important goal by using a combination of imaging modalities and their precise interpretation, which lends itself to understanding the mechanisms and pathophysiology of underlying disease, and therefore guides therapeutic decision-making in a patient-tailored fashion. This review explores the most commonly used brain imaging modalities, computer tomography, and magnetic resonance imaging, with an aim to demonstrate their dynamic use in uncovering stroke mechanism, facilitating prognostication, and potentially guiding therapy.

Imaging of Cerebral Ischemia : From Acute Stroke to Chronic Disorders

Cerebral ischemia manifests widely in patient symptoms. Along with the clinical examination, imaging serves as a powerful tool throughout the course of ischemia-from acute onset to evolution. A thorough understanding of imaging modalities, their strengths and their limitations, is essential for capitalizing on the benefit of this complementary source of information for understanding the mechanism of disease, making therapeutic decisions, and monitoring patient response over time.

Intraosseous Administration of Tissue Plasminogen Activator on a Mobile Stroke Unit

Abstract Objective: Mobile stroke units offer improved time to administration of thrombolytics for ischemic stroke patients. Acquisition of intravenous (IV) access, however, can be challenging in the prehospital environment leading to treatment delays. Intraosseous (IO) access is commonly used in the prehospital setting for a variety of conditions and may serve as a viable means for tPA (tissue plasminogen activator) administration. Methods/Results: We describe 3 cases in which tPA was administered via IO access on a mobile stroke unit as part of the Benefits of Stroke Treatment Delivered Using a Mobile Stroke Unit Compared to Standard Management by Emergency Medical Services (BEST-MSU) trial. Conclusion: No adverse events were observed in the process of obtaining IO access or administering tPA.

The Frequency of Substantial Salvageable Penumbra in Thrombectomy-ineligible Patients with Acute Stroke: Frequency of Nonperfusable Penumbra

Endovascular therapy (ET) has become the standard of care for selected patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO). However, many LVO or medium vessel occlusion (MVO) patients are ineligible for ET, including some who harbor salvageable tissues. To develop complementary therapies for these patients, it is important to delineate their prevalence, clinical features, and outcomes.

Contents Vol. 1, 2012

132 9th International Stroke Summit July 5–7, 2013, Nanjing, China Chairpersons: Xinfeng Liu (Nanjing); Yangtai Guan (Shanghai); Chuanqiang Pu (Beijing); Suming Zhang (Wuhan); Gelin Xu (Nanjing)