Penumbra detection in acute stroke with perfusion magnetic resonance imaging: Validation with O-positron emission tomography.

Objective: Accurate identification of the ischemic penumbra, the therapeutic target in acute clinical stroke, is of critical importance to identify patients who might benefit from reperfusion therapies beyond the established time windows. Therefore, we aimed to validate magnetic resonance imaging (MRI) mismatch-based penumbra detection against full quantitative positron emission tomography ( O-PET), the gold standard for penumbra detection in acute ischemic stroke.

Methods: Ten patients (group A) with acute and subacute ischemic stroke underwent perfusion-weighted (PW)/diffusion-weighted MRI and consecutive full quantitative O-PET within 48 hours of stroke onset.

Is Perfusion MRI without Deconvolution Reliable for Mismatch Detection in Acute Stroke? Validation with 15O-Positron Emission Tomography.

Background: In acute stroke, the magnetic resonance (MR) imaging-based mismatch concept is used to select patients with tissue at risk of infarction for reperfusion therapies. There is however a controversy if non-deconvolved or deconvolved perfusion weighted (PW) parameter maps perform better in tissue at risk prediction and which parameters and thresholds should be used to guide treatment decisions.

Methods: In a group of 22 acute stroke patients with consecutive MR and quantitative positron emission tomography (PET) imaging, non-deconvolved parameters were validated with the gold standard for penumbral-flow (PF) detection 15O-water PET.

Multiparametric Model for Penumbral Flow Prediction in Acute Stroke.

Background And Purpose: Identification of salvageable penumbra tissue by dynamic susceptibility contrast magnetic resonance imaging is a valuable tool for acute stroke patient stratification for treatment. However, prior studies have not attempted to combine the different perfusion maps into a predictive model. In this study, we established a multiparametric perfusion imaging model and cross-validated it using positron emission tomography perfusion for detection of penumbral flow.

A PET-Guided Framework Supports a Multiple Arterial Input Functions Approach in DSC-MRI in Acute Stroke.

Background And Purpose: In acute stroke, arterial-input-function (AIF) determination is essential for obtaining perfusion estimates with dynamic susceptibility-weighted contrast-enhanced magnetic resonance imaging (DSC-MRI). Standard DSC-MRI postprocessing applies single AIF selection, ie, global AIF. Physiological considerations, however, suggest that a multiple AIFs selection method would improve perfusion estimates to detect penumbral flow.

MRI-based mismatch detection in acute ischemic stroke: Optimal PWI maps and thresholds validated with PET.

Perfusion-weighted (PW) magnetic resonance imaging (MRI) is used to detect penumbral tissue in acute stroke, but the selection of optimal PW-maps and thresholds for tissue at risk detection remains a matter of debate. We validated the performance of PW-maps with 15O-water-positron emission tomography (PET) in a large comparative PET-MR cohort of acute stroke patients. In acute and subacute stroke patients with back-to-back MRI and PET imaging, PW-maps were validated with 15O-water-PET.

Clinical-Radiological Parameters Improve the Prediction of the Thrombolysis Time Window by Both MRI Signal Intensities and DWI-FLAIR Mismatch.

Background: With regard to acute stroke, patients with unknown time from stroke onset are not eligible for thrombolysis. Quantitative diffusion weighted imaging (DWI) and fluid attenuated inversion recovery (FLAIR) MRI relative signal intensity (rSI) biomarkers have been introduced to predict eligibility for thrombolysis, but have shown heterogeneous results in the past. In the present work, we investigated whether the inclusion of easily obtainable clinical-radiological parameters would improve the prediction of the thrombolysis time window by rSIs and compared their performance to the visual DWI-FLAIR mismatch.

Comparison of the 2 Most Popular Deconvolution Techniques for the Detection of Penumbral Flow in Acute Stroke.

Background And Purpose: Dynamic susceptibility-weighted contrast-enhanced (DSC) magnetic resonance imaging (MRI) is used to identify the tissue-at-risk in acute stroke, but the choice of optimal DSC postprocessing in the clinical setting remains a matter of debate. Using 15O-water positron emission tomography (PET), we validated the performance of 2 common deconvolution methods for DSC-MRI.

Methods: In (sub)acute stroke patients with consecutive MRI and PET imaging, DSC maps were calculated applying 2 deconvolution methods, standard and block-circulant single value decomposition.

DWI intensity values predict FLAIR lesions in acute ischemic stroke.

Background And Purpose: In acute stroke, the DWI-FLAIR mismatch allows for the allocation of patients to the thrombolysis window (<4.5 hours). FLAIR-lesions, however, may be challenging to assess.

Acute interventional recanalisation of vertebrobasilar stenoses by angioplasty: complications and 12 months follow up.

Introduction: In acute symptomatic vertebrobasilar artery stenosis, the use of mechanical recanalisation remains controversial. The complication rate of acute interventional recanalisation (aIR) has to be considered, as evidence from randomised trials is lacking. In a single centre retrospective case series, we here describe complications and outcome after aIR.

Influence of the arterial input function on absolute and relative perfusion-weighted imaging penumbral flow detection: a validation with ¹⁵O-water positron emission tomography.

Background And Purpose: Perfusion-weighted imaging maps are used to identify critical hypoperfusion in acute stroke. However, quantification of perfusion may depend on the choice of the arterial input function (AIF). Using quantitative positron emission tomography we evaluated the influence of the AIF location on maps of absolute and relative perfusion-weighted imaging to detect penumbral flow (PF; <20 mL/100 g/min on positron emission tomography(CBF)) in acute stroke.

Maps of time to maximum and time to peak for mismatch definition in clinical stroke studies validated with positron emission tomography.

Background And Purpose: Perfusion-weighted imaging-derived maps of time-to-maximum (Tmax) are increasingly used to identify the tissue at risk in clinical stroke studies (eg, DEFUSE and EPITHET). Using quantitative positron emission tomography (PET), we evaluated Tmax to define the penumbral flow threshold in stroke patients and compared its performance to nondeconvolved time-to-peak (TTP) maps.

Methods: Comparative perfusion-weighted imaging and quantitative 15O-water PET images of acute stroke patients were analyzed using cortical regions of interest.

A simple positron emission tomography-based calibration for perfusion-weighted magnetic resonance maps to optimize penumbral flow detection in acute stroke.

Background And Purpose: Perfusion-weighted (PW) MRI is increasingly used to identify the tissue at risk. The adequate PW-MRI map and threshold remain controversial due to a considerable individual variation of values. By comparative positron emission tomography, we evaluated a simple MR-based and positron emission tomography-validated calibration of PW maps.

Combined interventional stroke therapy using intracranial stent and local intraarterial thrombolysis (LIT).

Introduction: Supported by results of the ECASS III study, intravenous rt-PA thrombolysis is considered a standard therapy for acute stroke within 4.5 h. Still under debate is the use of a more aggressive treatment as that of local intraarterial thrombolysis (LIT) or combining intravenous administration of recombinant tissue plasminogen activator (rt-PA) followed by LIT (bridging concept).

MRI perfusion maps in acute stroke validated with 15O-water positron emission tomography.

Background And Purpose: Perfusion-weighted imaging maps are used to identify hypoperfusion in acute ischemic stroke. We evaluated maps of cerebral blood flow (CBF), cerebral blood volume, mean transit time, and time to peak (TTP) in acute stroke by comparison with positron emission tomography.

Methods: Perfusion-weighted imaging and positron emission tomography were performed in 26 patients with acute ischemic stroke (median 18.

Sequential escalation of therapy in "malignant" cerebral venous and sinus thrombosis.

Background: The best treatment of fulminant or progressive cerebral venous and sinus thrombosis (CVST) despite dose-adjusted heparin remains controversial. Local thrombolysis has been successfully performed in several cases. In cases of impending herniation hemicraniectomy has been suggested as ultima ratio.

The performance of MRI-based cerebral blood flow measurements in acute and subacute stroke compared with 15O-water positron emission tomography: identification of penumbral flow.

Background And Purpose: Perfusion-weighted MRI-based maps of cerebral blood flow (CBF(MRI)) are considered a good MRI measure of penumbral flow in acute ischemic stroke but are seldom used in clinical routine due to methodical issues. We validated CBF(MRI) on quantitative CBF measurement by 15O-water positron emission tomography (CBF(PET)).

Material And Methods: Comparative CBF(MRI) and CBF(PET) were performed in patients with acute and subacute stroke.

Rituximab in a patient with multiple sclerosis--effect on B cells, plasma cells and intrathecal IgG synthesis.

Objective: To study the time course of immunoglobulin, B and plasma cells in the blood and cerebrospinal fluid (CSF) before and during rituximab treatment in a patient with severe relapsing-remitting multiple sclerosis (MS) in relation to clinical and MRI findings.

Methods: Immunoglobulins in the CSF were measured by nephelometry and detected by isoelectrical focussing. CSF and blood cell subtypes from seven time points were analysed by flow cytometry.

Bilateral vertebral artery disease: transcranial Doppler assessment of the hemodynamic vulnerability to changes in posture.

Posture changes may cause hemodynamic ischemic events, particularly in severe vertebrobasilar artery disease. It may be difficult and not without risk to prove this vulnerability to changes in posture during angiography. Therefore, TCD monitoring with passive tilting (PT) was used to evaluate cerebral hemodynamics distally to severe bilateral vertebral artery disease (BVAD).

Proton magnetic resonance spectroscopy in ecstasy (MDMA) users.

The popular recreational drug 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) has well-recognized neurotoxic effects upon central serotonergic systems in animal studies. In humans, the use of MDMA has been linked to cognitive problems, particularly to deficits in long-term memory and learning. Recent studies with proton magnetic resonance spectroscopy (1H MRS) have reported relatively low levels of the neuronal marker N-acetylaspartate (NAA) in MDMA users, however, these results have been ambiguous.

Brain white-matter lesions in celiac disease: a prospective study of 75 diet-treated patients.

Objective: Celiac disease (CD), or gluten sensitivity, is considered to be a state of heightened immunologic responsiveness to ingested gluten proteins in genetically predisposed individuals. The gastrointestinal manifestation suggests a severe enteropathy of the small intestine with malabsorption, steatorrhea, and weight loss because of a deranged mucosal immune response. Neurologic complications occur, especially epilepsy, possibly associated with occipital calcifications or folate deficiency and cerebellar ataxia.