We performed a preliminary feasibility and safety study using intravenous (IV) administration of a platelet glycoprotein IIb/IIIa inhibitor (abciximab) in conjunction with intraarterial (IA) administration of a thrombolytic agent (reteplase) in a primate model of intracranial thrombosis. We introduced thrombus through superselective catheterization of the intracranial segment of the internal ...

PURPOSE: To describe the findings of hyperperfusion on perfusion computed tomography (CT) in four patients following revascularization for acute stroke. MATERIAL AND METHODS: In 2002-2003, among a series of 6 patients presenting with an acute stroke and treated with intra-arterial thrombolysis, we observed the presence of hyperperfusion in 3 patients ...

Increased risk of hemorrhagic transformation (HT) limits the general use of thrombolytic therapy in acute ischemic stroke (AIS). This study shows that early blood-brain barrier defects in AIS can be assessed by using permeability MR imaging. Significantly increased permeability was found in 3 patients who later hemorrhaged. This method indicates ...

OBJECTIVES: To assess the reliability and interobserver agreement of stroke identification on neuroimaging in patients presenting with dementia. DESIGN: Comparison study between neurologists, radiology reports, and autopsy. SETTING: Dementia registry within a health maintenance organization. PARTICIPANTS: Dementia patients with computed tomography (CT) scans obtained near the time of diagnosis and ...

It is thought that gray and white matter (GM and WM) have different perfusion and diffusion thresholds for cerebral infarction in humans. We sought to determine these thresholds with voxel-by-voxel, tissue-specific analysis of co-registered acute and follow-up magnetic resonance (MR) perfusion- and diffusion-weighted imaging. Quantitative cerebral blood flow (CBF), cerebral ...

AIM: A rapid assessment stroke clinic (RASC) was established to provide a rapid diagnostic service to individuals with suspected transient cerebral or ocular ischaemia or recovered non-hospitalized strokes. In this report we review imaging findings and clinical outcomes of patients proceeding to the carotid surgery programme. METHODS: Between October 2000 ...

BACKGROUND AND PURPOSE: Substantial variability in functional outcome and relatively few factors predictive of death or degree of recovery have been observed in patients with lacunar stroke. Such indicators are of great use in the selection of optimal rehabilitation strategies after stroke. Although computed tomography (CT) of patients with a ...

BACKGROUND: Orolingual angioedema can occur during thrombolysis with alteplase in stroke patients. However, data about its frequency, severity and the significance of concurrent use of angiotensin-converting-enzyme inhibitors (ACEi) are sparse. OBJECTIVE: (1), to alert to the potentially life-threatening complication of orolingual angioedema. (2), to present CT-scans of the tongue which ...

Stroke is a leading cause of long-term disability in adults worldwide. The mechanisms of impairment and recovery are not well understood, but there is growing interest in the role that central nervous system reorganization might play. Functional magnetic resonance imaging and transcranial magnetic stimulation allow the non-invasive study of the ...

BACKGROUND AND PURPOSE: The importance of early ischemic change (EIC) on baseline computed tomography (CT) in the decision to thrombolyze the patient with acute ischemic stroke has been controversial. ASPECTS is a semiquantitative scale that scores the extent of EIC within the middle cerebral artery territory. We examined whether ASPECTS ...

Though basal ganglia calcification (BGC) has been recognized as a feature of mitochondriopathy, little is known about its frequency in a larger cohort. The aim of this work was to assess the frequency of BGC, type and frequency of clinical and additional imaging central-nervous-system (CNS) abnormalities and of non-CNS abnormalities ...

A 78-year-old woman suffered a stroke inside a magnetic resonance scanner while being imaged because of a brief transient ischemic attack 2 hours earlier. Diffusion-weighted images obtained 11 minutes after stroke showed tissue injury not found on initial images. The data show early, abrupt diffusion changes in hypoperfused tissue, adding ...

OBJECTIVES: Infarct volume correlation using magnetic resonance imaging (MRI) and pathology specimens enables exact tissue localization of cerebral injury following experimental stroke. We describe a protocol that enables co-registration of radiographic signal change and histologic ischemia in a non-human primate model of stroke. METHODS: One male baboon underwent left middle ...

The mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes syndrome (MELAS) is a rare congenital disorder of mitochondrial DNA (mtDNA). Herein we report a case of MELAS, whose second stroke-like episode was provoked by chickenpox. A point mutation at nucleotide (nt) 3243 in mtDNA supported the diagnosis of MELAS in ...

BACKGROUND AND PURPOSE: There is little agreement on how to assess outcome in acute stroke trials. Cutoff scores for the Barthel Index (BI) and modified Rankin Scale (mRS) are frequently arbitrarily chosen to dichotomize favorable and unfavorable outcome. We investigated sensitivity and specificity of BI cutoff scores in relation to ...

There is increasing interest in using diffusion-weighted (DWI) MR imaging and perfusion-weighted MR imaging (PWI) to assist clinical decision-making in the management of acute stroke patients. Larger PWI than DWI lesions have been speculated to represent potentially salvageable tissue that is at risk of infarction unless nutritive flow is restored ...

As new treatments are developed for stroke, the potential clinical applications of CT perfusion (CTP) imaging in the diagnosis, triage, and therapeutic monitoring of these diseases are certain to increase. Technical advances in scanner hardware and software should no doubt continue to increase the speed, coverage, and resolution of CTP ...

We employed a dynamically scaled mechanical model of the small fruit fly Drosophila melanogaster (Reynolds number 100-200) to investigate force enhancement due to contralateral wing interactions during stroke reversal (the ;clap-and-fling'). The results suggest that lift enhancement during clap-and-fling requires an angular separation between the two wings of no more ...

Data from intravenous tissue plasminogen activator studies have shown rapidly diminishing clinical benefit beyond 3 hours when noncontrast CT is used for treatment triage. Newer trials, such as the Desmoteplase in Acute Ischemic Stroke trial, have now successfully pushed the time window out to 9 hours using the concept of ...

BACKGROUND: Cerebrovascular Accident or stroke is a major cause of morbidity and mortality. For any treatment to be contemplated it is important to know whether we are dealing with a bleed or an infarct. This study was carried out to compare clinical diagnosis of stroke with Computed tomography (CT) scan ...

Multimodality magnetic resonance imaging (MRI) techniques, including diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI), fluid-attenuated inversion recovery (FLAIR), T2 susceptibility imaging, and magnetic resonance angiography (MRA), quickly provide accurate information about ischemic penumbra (DWI/PWI mismatch), tissue perfusion, and vascular localization in acute stroke setting. These techniques help physicians to select the ...

INTRODUCTION: Microhemorrhages seen on gradient-echo magnetic resonance imaging are thought to be a manifestation of small-vessel disease. It was the aim of our study to evaluate the prevalence of microhemorrhage for patients presenting with acute lacunar infarction. METHODS: We obtained gradient-echo and diffusion-weighted magnetic resonance imaging as part of the ...

Imaging in a patient suspected of having suffered an acute stroke is used primarily to clear the patient for thrombolytic therapy, by excluding intracranial hemorrhage and nonstroke causes of the patient's symptoms, within a critical 3-hour window. Noncontrast CT of the brain is the imaging test of choice for the ...

BACKGROUND AND PURPOSE: Diffusion-and perfusion-weighted magnetic resonance imaging (DWI and PWI) are useful tools for the assessment of brain ischemia. Discrepancies between the extent of DWI and PWI abnormalities are thought to depend pre dominantly on time from symptom onset to magnetic resonance imaging (MRI) examination. However, underlying ischemic stroke ...

OBJECTIVE: To evaluate the technical feasibility of an integrated ultrafast head magnetic resonance (MR) protocol using a sensitivity encoding (SENSE) technique for depicting parenchymal ischaemia and vascular compromise in patients with suspected recent stroke. METHODS: 23 patients were evaluated with the ultrafast MR protocol using T2, T1, fluid attenuated inversion ...

PURPOSE: To determine the evolution of the ischemic lesion volumes in a population treated with tissue plasminogen activator (t-PA), MRIs were performed before treatment and 24 hours later; final infarct size was evaluated 60 days later. MATERIALS AND METHODS: A total of 42 patients with hemispheric stroke were recruited for ...

We examined whether the presence of diffusion-weighted imaging (DWI) lesions and vessel occlusion on acute brain magnetic resonance images of minor stroke and transient ischemic attack patients predicted the occurrence of subsequent stroke and functional outcome. 120 transient ischemic attack or minor stroke (National Institutes of Health Stroke Scale < ...

A 67-year-old woman with a recent history of recurrent ischemic stroke secondary to right vertebral artery stenosis suffered acute onset of left homonymous hemianopsia and the medial longitudinal fasciculus syndrome, which resolved with hyperdynamic therapy. However, consciousness deteriorated 6 hours later. Perfusion computed tomography (CT) revealed regions of prolonged mean ...

PURPOSE: To investigate the ability of map-ISODATA (Iterative Self-Organizing Data Analysis Technique) to classify the different categories of ischemic damage in the lesion and to evaluate a combined (thrombolysis plus antiplatelet) treatment efficacy in an embolic stroke of rat. MATERIALS AND METHODS: Rats subjected to embolic stroke with (N=12) and ...

BACKGROUND AND PURPOSE: Our goal was to develop magnetic resonance indices, without image contrast agent enhancement, that predict hemorrhagic transformation (HT) in a rat model of embolic stroke. METHODS: Male Wistar rats subjected to embolic stroke with (n=12) or without (n=10) the combination treatment with recombinant tissue plasminogen activator and ...

Brainstem infarcts comprise approximately 10% of all first ischemic brain strokes. The extrinsic vascular supply to the stem is complex. The intrinsic vascularization of the stem may be conceptualized in terms of four relatively constant and distinct vascular territories designated anteromedial, anterolateral, lateral, and dorsal (or dorsolateral). The anatomic structures ...

Unenhanced CT remains the most widely used imaging technique and is the standard of care for acute stroke evaluation. Early ischemic signs (EIS) within the first 3 to 6 hours of symptom onset (eg, parenchymal hypodensity, sulcal effacement, and dense vessel) have been advocated as a triage tool for thrombolytic ...

In early trials of thrombolysis, unenhanced CT was used to exclude patients with brain hemorrhage or large infarctions but was insensitive to stroke pathophysiology or early signs of cerebral ischemia or infarction. Currently, CT angiography, CT perfusion, and MR imaging can provide information about stroke mechanisms and prognosis, quantify penumbral ...

The anatomic description of the stroke lesion is an essential component of clinical diagnosis and treatment and has become an established tool in investigations into underlying stroke pathophysiology. Magnetic resonance (MR) imaging permits quantitative evaluation of the distributed consequences of the pathologic stroke insult. General properties of stroke effects have ...

In the setting of acute stroke evaluation, CT is accessible, versatile, available, inexpensive, and, most importantly, fast. Its use extends beyond that of identifying intracranial hemorrhage. We have emphasized the importance of clinical assessment, supported by a systematic approach to unenhanced CT interpretation using the Alberta Stroke Program Early CT ...

Ipsilateral hemiparesis after a supratentorial stroke is rare. However, the role of the reorganization of the unaffected hemisphere in recovery after a stroke is poorly understood. Two patients developed ipsilateral hemiparesis after a left corona radiata infarct. Both of these patients had previously experienced contralateral hemiparesis after a right-sided supratentorial ...

We have developed a new three dimensional (3-D) conductivity imaging approach and have used it to detect human brain conductivity changes corresponding to acute cerebral stroke. The proposed Magnetic Resonance Electrical Impedance Tomography (MREIT) approach is based on the J-Substitution algorithm and is expanded to imaging 3-D subject conductivity distribution ...

New and more advanced diagnostic imaging techniques for acute stroke triage have the potential to not only improve the quality of care but also reduce health care costs. Although sufficiently large and methodologically sound studies with regard to cost effectiveness of MR imaging are lacking, the overall impression is that ...

Ultrahigh-field MRI at 8 T offers unprecedented resolution for imaging brain structures and microvasculature. The aim of this study is to apply high-resolution MRI for stroke imaging and to characterize findings at 1.5 and 8 T. Seventeen subjects with minor ischemic infarcts were studied using T2-weighted gradient echo (GE) and ...

In this study we evaluated the presence of patent foramen ovale (PFO) in a cohort of 25 consecutive patients suffering from migraine with aura (MA) during an attack presenting to the emergency ward of an Italian hospital. Patients underwent brain magnetic resonance imaging (MRI) with contrast medium, routine coagulation tests, ...

BACKGROUND AND PURPOSE: The volume of decreased cerebral blood flow (CBF) in acute stroke perfusion-weighted imaging frequently overestimates final infarct volume. We hypothesized that surviving tissue exists even in patients without recanalization and tried to determine perfusion thresholds from initial MR imaging. METHODS: Stroke MR imaging including MR angiography was ...

PURPOSE: To investigate infarct evolution and functional consequences of exclusive subcortical or cortico-subcortical strokes, transient middle cerebral artery occlusion (MCAO) was conducted in Wistar rats. MATERIALS AND METHODS: MCAO was induced in male Wistar rats (260-300 g) for 60 minutes. Lesion volumes and absolute T2 times on magnetic resonance imaging ...

Although diffusion-weighted (DW) magnetic resonance (MR) imaging can detect hyperacute ischemic parenchyma with high sensitivity, the ability of DW images to reveal subtle change in abnormal diffusion may be limited by the conventional visual evaluation. To overcome the limitation, we have developed a method of transparent color-coded three-dimensional (3D) DW ...

BACKGROUND: Introduction of helical computed tomography (CT) scanning has enabled rapid imaging of the vascular status by means of CT angiography and perfusion CT. By virtue of recent multi-detector technology, helical CT has the ability to perform both CT angiography and multi-section perfusion CT simultaneously. This study investigated the clinical ...

One of the main reasons for the soaring interest in acute ischemic stroke among radiologists is the advent of new magnetic resonance techniques such as diffusion-weighted imaging. This new modality has prompted us to seek a better understanding of the pathophysiologic mechanisms of cerebral ischemia/infarction. The ischemic penumbra is an ...

BACKGROUND AND PURPOSE: In ischemic stroke, diffusion-weighted (DW) and perfusion-weighted (PW) magnet resonance imaging (MRI) is used to define the mismatch as the therapeutic target. With positron emission tomography (PET), we characterized the metabolic patterns of tissue compartments identified by MRI and compared the volumes of mismatch to those of ...

The site of lesion responsible for left hemispatial neglect after stroke has been intensely debated recently. Some studies provide evidence that right angular lesions are most likely to cause left neglect, whereas others indicate that right superior temporal lesions are most likely to cause neglect. We examine two potential accounts ...

206 patients clinically diagnosed as stroke / cerebrovascular accidents (CVA) were investigated using computerized tomography (CT) scan. 19 patients (9%) had normal scan. While 20(9.7%) had other lesions including atrophy and tumours. Of the 167 (18. %) patients proven to have suffered a cerebro- vascular accident (CVA/stroke), 73 (43.7 %) ...

BACKGROUND AND PURPOSE: Analogous to the CT hyperattenuated vessel sign (HMCAS), MR imaging may show hypo- or hyperintense vessels in acute ischemic stroke (AIS) patients. We assessed the diagnostic and prognostic strength of early MR imaging vessel signs in AIS patients treated with intravenous thrombolysis (IVT) within 3 hours of ...

The recent failure of many clinical trials of neuroprotective compounds may be due in part to poor animal models of human stroke. We have developed an endovascular stroke model in nonhuman primates that is compatible with serial magnetic resonance imaging (MRI) monitoring. Using cynomologous macaques (n = 4), a microcatheter ...