The presence of distal hyperintense vessels before thrombolytic treatment is associated with large diffusion-perfusion mismatch and smaller subacute ischemic lesion volumes in patients with proximal middle cerebral artery occlusion. DWI = diffusion-weighted imaging; FLAIR = fluid-attenuated inversion recovery; GRE = gradient recalled echo; HV = hyperintense vessels; MCA = middle cerebral artery; MRA = magnetic resonance angiography; MTT = mean transit time; NIHSS = NIH Stroke Scale; PWI = perfusion-weighted imaging; rt-PA = recombinant tissue plasminogen activator; TE = echo time; TI = inversion time; TIMI = thrombolysis in myocardial infarction; TR = repetition time.

Objective-Outcome prediction is challenging in comatose post-cardiac arrest survivors. We assessed the feasibility and prognostic utility of brain diffusion-weighted MRI (DWI) during the first week.Corresponding Author Christine AC Wijman, MD, PhD, Stanford Stroke Center, 701 Welch Road, B325, Palo Alto, CA 94304, Fax: (650) Tel: (650) NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptMethods-Consecutive comatose post-cardiac arrest patients were prospectively enrolled. MRI data of patients who met predefined specific prognostic criteria were used to determine distinguishing ADC thresholds. Group 1: death at 6 months and absent motor response or absent pupillary reflexes or bilateral absent cortical responses at 72 hours, or vegetative at 1 month. Group 2A: Glasgow outcome scale (GOS) score of 4 or 5 at 6 months. Group 2B: GOS of 3 at 6 months. The percentage of voxels below different apparent diffusion coefficient (ADC) thresholds was calculated at 50 × 10 −6 mm 2 /sec intervals.Results-Overall, 86% of patients underwent MR imaging. Fifty-one patients with 62 brain MRIs were included in the analyses. Forty patients met the specific prognostic criteria. The percentage of brain volume with an ADC value below 650-700 × 10 −6 mm 2 /sec best differentiated between group 1 and groups 2A and 2B combined (p<0.001), while the 400-450 × 10 −6 mm 2 /sec threshold best differentiated between groups 2A and 2B (p=0.003). The ideal time window for prognostication using DWI was between 49 to 108 hours after the arrest. When comparing MRI in this time window with the 72 hour neurological examination MRI improved the sensitivity for predicting poor outcome by 38% while maintaining 100% specificity (p=0.021).Interpretation-Quantitative DWI in comatose post-cardiac arrest survivors holds great promise as a prognostic adjunct.Approximately 350,000 cardiac arrests occur annually in the United States1. Up to half of these patients are successfully resuscitated. In the past, only 10% to 30% of comatose postcardiac arrest patients had good functional recovery. These numbers will likely improve with the increasing use of therapeutic hypothermia2 , 3.Post-cardiac arrest brain injury is a common cause of morbidity and mortality. Many comatose post-cardiac arrest patients die or survive with severe disability after a prolonged intensive care unit stay associated with a tremendous cost burden4 , 5. Conversely, the potential for premature withdrawal of life support from patients who may have a chance of functional recovery represents an additional ethical dilemma. Thus, early accurate identification of patients who have no likelihood of meaningful recovery is a very important health care issue.Although several prognostic variables have been studied in comatose post-cardiac arrest patients, the currently accepted variables (neurological examination, neurophysiologic tests, and serum markers) have substantive limitations. First, they identify only a subset of poor outcome patients with high specificity. Se...

Background and Purpose-Diffusion-weighted magnetic resonance imaging of the brain is a promising technique to help predict functional outcome in comatose survivors of cardiac arrest. We aimed to evaluate prospectively the temporal-spatial profile of brain apparent diffusion coefficient changes in comatose survivors during the first 8 days after cardiac arrest. Methods-Apparent diffusion coefficient values were measured by 2 independent and blinded investigators in predefined brain regions in 18 good-and 15 poor-outcome patients with 38 brain magnetic resonance imaging scans and were compared with those of 14 normal controls. The same brain regions were also assessed qualitatively by 2 other independent and blinded investigators. Results-In poor-outcome patients, cortical structures, in particular the occipital and temporal lobes, and the putamen exhibited the most profound apparent diffusion coefficient reductions, which were noted as early as 1.5 days and reached a nadir between 3 and 5 days after the arrest. Conversely, when compared with normal controls, good-outcome patients exhibited increased diffusivity, in particular in the hippocampus, temporal and occipital lobes, and corona radiata. By qualitative magnetic resonance imaging readings, 1 or more cortical gray matter structures were judged to be moderately to severely abnormal in all poor-outcome patients except for the 3 patients imaged within 24 hours after the arrest. Conclusions-Brain diffusion-weighted imaging changes in comatose, postcardiac arrest survivors in the first week after the arrest are region and time dependent and differ between good-and poor-outcome patients. With increasing use of magnetic resonance imaging in this context, it is important to be aware of these relations. (Stroke. 2010;41:1665-1672.)

Background Some patients seen by a stroke team do not have cerebrovascular disease but a condition that mimics stroke. The purpose of this study was to determine the rate and predictors of stroke mimics in a large sample. Methods This is an analysis of data from consecutive patients seen by the NIH Stroke Program over 10 years. Data were collected prospectively as a quality improvement initiative. Patients with a cerebrovascular event or a stroke mimic were compared with the Student t or Pearson’s chi-square test as appropriate and logistic regression was done to identify independent predictors. Results The analysis included 8,187 patients: 30% had a stroke mimic. Patients with a stroke mimic were younger and the proportion of patients with a stroke mimic was higher among women, patients without any risk factors, those seen as a code stroke or who arrived to the emergency department via personal vehicle, and those who had the onset of symptoms while inpatients. The proportion of patients with a stroke mimic was marginally higher among African Americans than Caucasians. Factors associated with the greatest odds of having a stroke mimic in the logistic regression were lack of a history of hypertension atrial fibrillation, or hyperlipidemia. Conclusions A third of the patients seen by a stroke team over 10 years had a stroke mimic. Factors associated with a stroke mimic may be ascertained by an emergency physician before calling the stroke team.

Intravenous thrombolysis within 4.5 hours of symptom discovery in patients with unwitnessed stroke selected by qDFM, who are beyond the recommended time windows, is safe. A randomized trial testing efficacy using qDFM appears feasible and is warranted in patients without large vessel occlusions. Ann Neurol 2018;83:980-993.

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Cerebrovascular injuries can cause severe edema and inflammation that adversely affect human health. Here, we observed recanalization after successful endovascular thrombectomy for acute large vessel occlusion was associated with cerebral edema and poor clinical outcomes in patients who experienced hemorrhagic transformation. To understand this process, we developed a cerebrovascular injury model using transcranial ultrasound that enabled spatiotemporal evaluation of resident and peripheral myeloid cells. We discovered that injurious and reparative responses diverged based on time and cellular origin. Resident microglia initially stabilized damaged vessels in a purinergic receptor-dependent manner, which was followed by influx of myelomonocytic cells that caused severe edema. Prolonged blockade of myeloid cell recruitment with anti-adhesion molecule therapy prevented severe edema but also promoted neuronal destruction and fibrosis by interfering with vascular repair later orchestrated by pro-inflammatory monocytes and pro-angiogenic repair-associated microglia (RAM). These data demonstrate how temporally distinct myeloid cell responses can contain, exacerbate, and ultimately repair a cerebrovascular injury.

Background Some prior studies have shown that racial disparities exist in intravenous tissue plasminogen activator (IV tPA) utilization for acute ischemic stroke. We sought to determine whether race was associated with tPA treatment for stroke in a predominantly black urban population. Methods Systematic chart abstraction was performed on consecutive hospitalized ischemic stroke patients from all seven acute care hospitals in the District of Columbia from Feb 1, 2008 to Jan 31, 2009. Results Of 1044 ischemic stroke patients, 74%% were black, 19% non-Hispanic white, 5% received IV tPA. Blacks were one third less likely than whites to receive IV tPA (3% vs. 10%, p<0.001). However, blacks were also less likely than whites to present within 3 hours of symptom onset (13% vs. 21%, p=0.004) and also less likely to be tPA-eligible (5% vs. 13%, p<0.001). Of those who presented within 3 hours, blacks were almost half as likely to be treated with IV tPA than whites (27% vs. 46%, p=0.023). The treatment rate for tPA-eligible patients was similar for blacks and whites (70% vs. 76%, p=0.62). Conclusions In this predominantly black urban population hospitalized for acute ischemic stroke, blacks were significantly less likely to be treated with IV tPA due to contraindications to treatment, delayed presentation, and stroke severity. Effective interventions designed to increase treatment in this population need to focus on culturally relevant education programs designed to address barriers specific to this population.