Finding MeVO: Identifying Intracranial Medium-Vessel Occlusions at CT Angiography.

The development of methods to detect and treat intracranial large-vessel occlusions (LVOs) has revolutionized the management of acute ischemic stroke. CT angiography (CTA) of the head and neck is effective in depicting LVOs and widely used in the evaluation of patients who have had a stroke. Ongoing efforts are now focused on the potential to detect and treat intracranial medium-vessel occlusions (MeVOs), which by definition are smaller than LVOs and thus more difficult to detect with CTA.

Location-atypical lesions in non-ketotic hyperglycemic epilepsy: expanding the clinico-radiographic phenotype.

Non-ketotic hyperglycemia (NKH) is associated with a spectrum of symptoms and radiographic findings due to poorly-controlled diabetes mellitus. These lesions, which predominantly affect the parieto-occipital cortex, are commonly missed by neurologists and neuroradiologists due to their subtle hypointense appearance on T2-based imaging. We report four atypical cases of this syndrome to highlight its subtle, protean presentation in order to aid timely diagnosis.

Performance of Automated RAPID Intracranial Hemorrhage Detection in Real-World Practice: A Single-Institution Experience.

Background And Purpose: Intracranial hemorrhage (ICH) is a common finding in patients presenting to the emergency department with acute neurological symptoms. Noncontrast head computed tomography (NCCT) is the primary modality for assessment and detection of ICH in the acute setting. RAPID ICH software aims to automatically detect ICH on NCCT and was previously shown to have high accuracy when applied to a curated test data set.

Silent Infarcts, White Matter Integrity, and Oxygen Metabolic Stress in Young Adults With and Without Sickle Cell Trait.

Background: Individuals with sickle cell anemia have heightened risk of stroke and cognitive dysfunction. Given its high prevalence globally, whether sickle cell trait (SCT) is a risk factor for neurological injury has been of interest; however, data have been limited. We hypothesized that young, healthy adults with SCT would show normal cerebrovascular structure and hemodynamic function.

Cerebral Oxygen Metabolic Stress, Microstructural Injury, and Infarction in Adults With Sickle Cell Disease.

Objective: To determine the patient- and tissue-based relationships between cerebral hemodynamic and oxygen metabolic stress, microstructural injury, and infarct location in adults with sickle cell disease (SCD).

Methods: Control participants and patients with SCD underwent brain MRI to quantify cerebral blood flow (CBF), oxygen extraction fraction (OEF), mean diffusivity (MD), and fractional anisotropy (FA) within normal-appearing white matter (NAWM) and infarcts on fluid-attenuated inversion recovery. Multivariable linear regression examined the patient- and voxel-based associations between hemodynamic and metabolic stress (defined as elevated CBF and OEF, respectively), white matter microstructure, and infarct location.

Utility of CT angiography in screening for traumatic cerebrovascular injury.

Objective: Computed tomographic angiography (CTA) is increasingly utilized to evaluate for traumatic cerebrovascular injury (TCVI). The purpose of this study was to determine the yield, management effect, and risk of stroke or poor outcome of a positive CTA in a large cohort of trauma patients.

Patients And Methods: A retrospective analysis was performed on 1290 consecutive trauma patients that underwent head and/or neck CTA at our level I trauma center from 2006 to 2015.

Regional oxygen extraction predicts border zone vulnerability to stroke in sickle cell disease.

Objective: To determine mechanisms underlying regional vulnerability to infarction in sickle cell disease (SCD) by measuring voxel-wise cerebral blood flow (CBF), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen utilization (CMRO) in children with SCD.

Methods: Participants underwent brain MRIs to measure voxel-based CBF, OEF, and CMRO. An infarct heat map was created from an independent pediatric SCD cohort with silent infarcts and compared to prospectively obtained OEF maps.

Red cell exchange transfusions lower cerebral blood flow and oxygen extraction fraction in pediatric sickle cell anemia.

Blood transfusions are the mainstay of stroke prevention in pediatric sickle cell anemia (SCA), but the physiology conferring this benefit is unclear. Cerebral blood flow (CBF) and oxygen extraction fraction (OEF) are elevated in SCA, likely compensating for reduced arterial oxygen content (CaO). We hypothesized that exchange transfusions would decrease CBF and OEF by increasing CaO, thereby relieving cerebral oxygen metabolic stress.

Large-Vessel Vasculopathy in Children With Sickle Cell Disease: A Magnetic Resonance Imaging Study of Infarct Topography and Focal Atrophy.

Background: Large-vessel vasculopathy (LVV) increases stroke risk in pediatric sickle cell disease beyond the baseline elevated stroke risk in this vulnerable population. The mechanisms underlying this added risk and its unique impact on the developing brain are not established.

Methods: We analyzed magnetic resonance imaging and angiography scans of 66 children with sickle cell disease and infarcts by infarct density heatmaps and Jacobian determinants, a metric utilized to delineate focal volume change, to investigate if infarct location, volume, frequency, and cerebral atrophy differed among hemispheres with and without LVV.

Neurologic and neuroimaging manifestations of Cantú syndrome: A case series.

Objective: To describe the neurologic and neuroimaging manifestations associated with Cantú syndrome.

Methods: We evaluated 10 patients with genetically confirmed Cantú syndrome. All adult patients, and pediatric patients who were able to cooperate and complete the studies, underwent neuroimaging, including vascular imaging.

Spinolaminar Line Test as a Screening Tool for C1 Stenosis.

Study Design Retrospective cohort. Objective To clarify the sensitivity of C3-C2 spinolaminar line test as a screening tool for the stenosis of C1 space available for the cord (SAC). Methods Spine clinic records from April 2005 to August 2011 were reviewed.

Streamlined Hyperacute Magnetic Resonance Imaging Protocol Identifies Tissue-Type Plasminogen Activator-Eligible Stroke Patients When Clinical Impression Is Stroke Mimic.

Background And Purpose: Stroke mimics (SM) challenge the initial assessment of patients presenting with possible acute ischemic stroke (AIS). When SM is considered likely, intravenous tissue-type plasminogen activator (tPA) may be withheld, risking an opportunity to treat AIS. Although computed tomography is routinely used for tPA decision making, magnetic resonance imaging (MRI) may diagnose AIS when SM is favored but not certain.

Reperfusion Beyond 6 Hours Reduces Infarct Probability in Moderately Ischemic Brain Tissue.

Background And Purpose: We aimed to examine perfusion changes between 3 and 6 and 6 and 24 hours after stroke onset and their impact on tissue outcome.

Methods: Acute ischemic stroke patients underwent perfusion magnetic resonance imaging at 3, 6, and 24 hours after stroke onset and follow-up fluid-attenuated inversion recovery at 1 month to assess tissue fate. Mean transit time prolongation maps (MTTp=MTT-[median MTT of contralateral hemisphere]) were obtained at 3 (MTTp3 h), 6 (MTTp6 h), and 24 hours (MTTp24 h).

Defining the ischemic penumbra using magnetic resonance oxygen metabolic index.

Background And Purpose: Penumbral biomarkers promise to individualize treatment windows in acute ischemic stroke. We used a novel magnetic resonance imaging approach that measures oxygen metabolic index (OMI), a parameter closely related to positron emission tomography-derived cerebral metabolic rate of oxygen utilization (CMRO2), to derive a pair of ischemic thresholds: (1) an irreversible-injury threshold that differentiates ischemic core from penumbra and (2) a reversible-injury threshold that differentiates penumbra from tissue not-at-risk for infarction.

Methods: Forty patients with acute ischemic stroke underwent magnetic resonance imaging at 3 time points after stroke onset: <4.

Imaging Oxygen Metabolism In Acute Stroke Using MRI.

The ability to image the ischemic penumbra during hyper-acute stroke promises to identify patients who may benefit from treatment intervention beyond population-defined therapeutic time windows. MR blood oxygenation level dependent (BOLD) contrast imaging has been explored in ischemic stroke. This review provides an overview of several BOLD-based methods, including susceptibility weighted imaging (SWI), R2, R2*, R2', R2* under oxygen challenge, MR_OEF and MROMI approaches to assess cerebral oxygen metabolism in ischemic stroke.

Clinically relevant reperfusion in acute ischemic stroke: MTT performs better than Tmax and TTP.

While several MRI parameters are used to assess tissue perfusion during hyperacute stroke, it is unclear which is optimal for measuring clinically relevant reperfusion. We directly compared mean transit time (MTT) prolongation (MTTp), time-to-peak (TTP), and time-to-maximum (Tmax) to determine which best predicted neurological improvement and tissue salvage following early reperfusion. Acute ischemic stroke patients underwent three MRIs: <4.

Defining the ischemic penumbra using hyperacute neuroimaging: deriving quantitative ischemic thresholds.

Despite three decades of promise, a neuroimaging biomarker capable of delineating the ischemic penumbra is yet to be definitively demonstrated. Much progress has been made, especially with MR imaging. However, in order to rigorously define an imaging biomarker of the ischemic penumbra, carefully designed studies which can derive ischemic thresholds using quantitative imaging parameters may be required.

Oxygen metabolism in ischemic stroke using magnetic resonance imaging.

Detecting "at-risk" but potentially salvageable brain tissue, known as the ischemic penumbra, is of importance for identifying patients who may benefit from thrombolytic or other treatments beyond the currently FDA-approved short therapeutic window for tissue plasminogen activator. Since the magnetic resonance blood oxygenation level-dependent (BOLD) contrast may provide information concerning tissue oxygen metabolism, its utilization in ischemic stroke has been explored. The focus of this review is to provide an introduction of several BOLD-based methods, including susceptibility-weighted imaging, R2 BOLD, R2*, R2', MR_OEF, and MR_OMI approaches to assess cerebral oxygenation changes induced by ischemia.

Accuracy of computed tomography detection of superior canal dehiscence.

Hypothesis: High-resolution temporal bone computed tomography (CT) may erroneously demonstrate a superior semicircular canal dehiscence (SSCD) where none exists and inaccurately display the size of a dehiscence.

Background: CT is an integral component of the diagnosis of SSCD. The prevalence of dehiscence as measured on computed tomographic scan is approximately eightfold higher than that on histologic studies, suggesting that CT may have a relatively low specificity for identifying canal dehiscence.

Preexisting statin use is associated with greater reperfusion in hyperacute ischemic stroke.

Background And Purpose: Statin pretreatment has been associated with improved outcomes in patients with ischemic stroke. Although several mechanisms have been examined in animal models, few have been examined in patients. We hypothesized that patients using statins before stroke onset may have greater reperfusion than patients not using statins.

Vascular permeability precedes spontaneous intracerebral hemorrhage in stroke-prone spontaneously hypertensive rats.

Background And Purpose: Stroke-prone spontaneous hypertensive rats (SHRsp) fed a high-salt diet develop malignant hypertension, blood-brain barrier breakdown, and spontaneous intracerebral hemorrhage (ICH). The precise spatial and temporal relationship between these events has not been well-delineated.

Methods: Ten SHRsp male rats, fed a high-salt diet, were imaged weekly using MRI, starting at 12 weeks of age.

Transient encephalopathy in a postoperative non-alcoholic female with Marchiafava-Bignami disease.

Marchiafava-Bignami disease (MBD) is historically reported in middle-aged alcoholic men. We describe the presentation, course and radiological findings of a young non-alcoholic woman who developed encephalopathy and MRI findings consistent with MBD postoperatively. She returned to baseline after vitamin supplementation.