Infarct Evolution on MR-DWI After Thrombectomy in Acute Stroke Patients Randomized to Nerinetide or Placebo: The REPERFUSE-NA1 Study.

Background And Objectives: The neuroprotectant nerinetide has shown promise in reducing infarct volumes in primate models of ischemia reperfusion. We hypothesized that early secondary infarct growth after endovascular therapy (EVT) (1) may be a suitable surrogate biomarker for testing neuroprotective compounds, (2) is feasible to assess in the acute setting using sequential MRI, and (3) can be modified by treatment with nerinetide.

Methods: REPERFUSE-NA1 was a prospective, multisite MRI substudy of the randomized controlled trial ESCAPE-NA1 (ClinicalTrials.

Visualization of atrophy of medial temporal lobes and the septal nuclei in patients with transient ischaemic attack and controls.

Introduction: Transient ischaemic attack (TIA) is associated with increased risk of cognitive decline and dementia as early as one-year post-event. Regional brain atrophy measurements may predict future cognitive decline. 1) To determine whether Medial Temporal Atrophy (MTA) scores and interseptal distance (ISD) measurements are greater in patients with TIA compared to controls; and 2) To determine whether MTA and ISD predicts cognitive change one year after TIA.

Arterial spin labelling reveals multi-regional cerebral hypoperfusion in patients with transient ischemic attack that are unrelated to ischemia location: A proof-of-concept study.

Background And Aims: Patients with transient ischemic attack (TIA) have a substantially increased risk of early dementia. In this exploratory study, we aim to determine whether patients with TIA have 1) measurable regional cerebral hypoperfusion unrelated to the location of ischemia, and 2) determine the relationship of regional cerebral blood flow (rCBF) with their cognitive profiles.

Methods: Patients with TIA ( = 49) and seventy-nine ( = 79) age and sex matched controls underwent formal neuropsychological testing and MRI.

Acute stroke imaging selection for mechanical thrombectomy in the extended time window: is it time to go back to basics? A review of current evidence.

Treatment with endovascular therapy in the extended time window for acute ischaemic stroke with large vessel occlusion involves stringent selection criteria based on the two landmark studies DAWN and DEFUSE3. Current protocols typically include the requirement of advanced perfusion imaging which may exclude a substantial proportion of patients from receiving a potentially effective therapy. Efforts to offer endovascular reperfusion therapies to all appropriate candidates may be facilitated by the use of simplified imaging selection paradigms with widely available basic imaging techniques, such as non-contrast CT and CT angiography.

White matter tract microstructure and cognitive performance after transient ischemic attack.

Background And Purpose: Patients with transient ischemic attack (TIA) show evidence of cognitive impairment but the reason is not clear. Measurement of microstructural changes in white matter (WM) using diffusion tensor imaging (DTI) may be a useful outcome measure. We report WM changes using DTI and the relationship with neuropsychological performance in a cohort of transient ischemic attack (TIA) and non-TIA subjects.

Dynamic CTA-Derived Perfusion Maps Predict Final Infarct Volume: The Simple Perfusion Reconstruction Algorithm.

Background And Purpose: Infarct core volume measurement using CTP (CT perfusion) is a mainstay paradigm for stroke treatment decision-making. Yet, there are several downfalls with cine CTP technology that can be overcome by adopting the simple perfusion reconstruction algorithm (SPIRAL) derived from multiphase CTA. We compare SPIRAL with CTP parameters for the prediction of 24-hour infarction.

Automatic arterial input function selection in CT and MR perfusion datasets using deep convolutional neural networks.

Purpose: The computation of perfusion parameter images requires knowledge of the arterial blood flow in the form of an arterial input function (AIF). This work proposes a novel method to automatically identify AIFs in computed tomography perfusion (CTP) and dynamic susceptibility contrast perfusion-weighted MRI (PWI) datasets using a deep convolutional neural network (CNN).

Methods: One-hundred CTP and 100 PWI datasets of acute ischemic stroke patients were available for model development and evaluation.

Recanalization following Endovascular treatment and imaging of PErfusion, Regional inFarction and atrophy to Understand Stroke Evolution-NA1 (REPERFUSE-NA1).

Rationale: Following endovascular treatment, poor clinical outcomes are more frequent if the initial infarct core or volume of irreversible brain damage is large. Clinical outcomes may be improved using neuroprotective agents that reduce stroke volume and improve recovery.

Aim: The aim of the REPERFUSE NA1 was to replicate the preclinical neuroprotection study that significantly reduced infarct volume in a primate model of ischemia reperfusion.

Temporal evolution and spatial distribution of quantitative T2 MRI following acute ischemia reperfusion injury.

Background: Determining mechanisms of secondary stroke injury related to cerebral blood flow and the severity of microvascular injury contributing to edema and blood-brain barrier breakdown will be critical for the development of adjuvant therapies for revascularization treatment.

Aim: To characterize the heterogeneity of the ischemic lesion using quantitative T2 imaging along with diffusion-weighted magnetic resonance imaging (DWI) within five hours of treatment.

Methods: Quantitative T2 magnetic resonance imaging was acquired within 5 h (baseline) and at 24 h (follow-up) of stroke treatment in 29 patients.

Correction to: Accuracy and Reliability of Multiphase CTA Perfusion for Identifying Ischemic Core.

Correction to: Clin Neuroradiol 2018 https://doi.org/10.1007/s00062-018-0717-x Unfortunately, the author list of the original version of this article contains a mistake.

CT perfusion measurement of postictal hypoperfusion: localization of the seizure onset zone and patterns of spread.

Purpose: Seizures are often followed by a period of transient neurological dysfunction and postictal alterations in cerebral blood flow may underlie these symptoms. Recent animal studies have shown reduced local cerebral blood flow at the seizure onset zone (SOZ) lasting approximately 1 h following seizures. Using arterial spin labelling (ASL) MRI, we observed postictal hypoperfusion at the SOZ in 75% of patients.

Longitudinal Brain Atrophy Rates in Transient Ischemic Attack and Minor Ischemic Stroke Patients and Cognitive Profiles.

Patients with transient ischemic attack (TIA) and minor stroke demonstrate cognitive impairment, and a four-fold risk of late-life dementia. To study the extent to which the rates of brain volume loss in TIA patients differ from healthy controls and how they are correlated with cognitive impairment. TIA or minor stroke patients were tested with a neuropsychological battery and underwent T1 weighted volumetric magnetic resonance imaging scans at fixed intervals over a 3 years period.

Quantitatively detecting postictal hypoperfusion in patients with focal epilepsy using CT perfusion: Determining cross-modality comparisons and electrode artifacts.

Background: We previously showed that CT perfusion (CTP) and arterial spin labelled (ASL) MRI can localize the seizure onset zone in humans via postictal perfusion patterns. As a step towards improving the feasibility/ease of collecting postictal CBF data, we determined whether EEG electrodes need to be removed for CTP data collection and whether a cross-modality comparison between baseline ASL and postictal CTP data is possible.

New Method: Five patients with epilepsy underwent postictal CTP scanning.

Diffusion-weighted imaging lesion growth occurs despite recanalization in acute ischemic stroke: Implications for future treatment trials.

Background: A proportion of patients presenting with acute small ischemic strokes have poor functional outcomes, even following rapid recanalization treatment.

Aims: Infarct growth may occur even after successful recanalization and could represent an appropriate endpoint for future stroke therapy trials.

Methods: Magnetic resonance diffusion-weighted imaging lesion volumes were obtained at 5 h (initial posttreatment) and 24 h (follow-up) after acute stroke treatment for n = 33 in ischemic stroke patients.

Accuracy and Reliability of Multiphase CTA Perfusion for Identifying Ischemic Core.

Purpose: Acute stroke treatment requires simple, quick and accurate detection of early ischemic changes to facilitate treatment decisions guided by published selection criteria. The aim of this study was to determine the accuracy and reliability of multiphase computed tomography angiography (mCTA) perfusion hypoattenuation for detecting early severe ischemia.

Methods: Non-contrast CT (NCCT), mCTA for regional leptomeningeal score (mCTA-rLMC), and mCTA perfusion lesion visibility (mCTA-arterial and mCTA-venous) were assessed blinded to clinical information in patients treated with endovascular therapy (EVT).

Absolute risk and predictors of the growth of acute spontaneous intracerebral haemorrhage: a systematic review and meta-analysis of individual patient data.

Background: Intracerebral haemorrhage growth is associated with poor clinical outcome and is a therapeutic target for improving outcome. We aimed to determine the absolute risk and predictors of intracerebral haemorrhage growth, develop and validate prediction models, and evaluate the added value of CT angiography.

Methods: In a systematic review of OVID MEDLINE-with additional hand-searching of relevant studies' bibliographies- from Jan 1, 1970, to Dec 31, 2015, we identified observational cohorts and randomised trials with repeat scanning protocols that included at least ten patients with acute intracerebral haemorrhage.

A longitudinal magnetic resonance imaging study of neurodegenerative and small vessel disease, and clinical cognitive trajectories in non demented patients with transient ischemic attack: the PREVENT study.

Background: Late-life cognitive decline, caused by progressive neuronal loss leading to brain atrophy years before symptoms are detected, is expected to double in Canada over the next two decades. Cognitive impairment in late life is attributed to vascular and lifestyle related risk factors in mid-life in a substantial proportion of cases (50%), thereby providing an opportunity for effective prevention of cognitive decline if incipient disease is detected earlier. Patients presenting with transient ischemic attack (TIA) commonly display some degree of cognitive impairment and are at a 4-fold increased risk of dementia.

Diffusion-Weighted MRI Stroke Volume Following Recanalization Treatment is Threshold-Dependent.

Purpose: Infarct lesion segmentation has been problematic as there are a wide range of relative and absolute diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) thresholds that have been used for this purpose. We examined differences of stroke lesion volume and evolution evaluated by magnetic resonance imaging (MRI) during the immediate post-treatment phase (<5 h) and at 24 h.

Methods: In this study 33 acute ischemic stroke patients were imaged with MRI <5 h and 24 h post-reperfusion treatment.

Neurovascular Unit: Basic and Clinical Imaging with Emphasis on Advantages of Ferumoxytol.

Physiological and pathological processes that increase or decrease the central nervous system's need for nutrients and oxygen via changes in local blood supply act primarily at the level of the neurovascular unit (NVU). The NVU consists of endothelial cells, associated blood-brain barrier tight junctions, basal lamina, pericytes, and parenchymal cells, including astrocytes, neurons, and interneurons. Knowledge of the NVU is essential for interpretation of central nervous system physiology and pathology as revealed by conventional and advanced imaging techniques.

Added value of multiphase CTA imaging for thrombus perviousness assessment.

Purpose: Thrombus perviousness has been associated with favorable functional outcome in acute ischemic stroke (AIS) patients. Measuring thrombus perviousness on CTA may be suboptimal due to potential delay in contrast agent arrival in occluded arteries at the moment of imaging. Dynamic sequences acquired over time can potentially overcome this issue.

Collateral Scoring on CT Angiogram Must Evaluate Phase and Regional Pattern.

Purpose: We measured anterior cerebral artery (ACA)-middle cerebral artery (MCA) and posterior cerebral artery (PCA)-MCA pial filling on single-phase computed tomography angiograms (sCTAs) in acute ischemic stroke and correlate with the CTA-based Massachusetts General Hospital (MGH) and digital subtraction angiography (DSA)-based American Society of Interventional and Therapeutic Neuroradiology (ASITN) score.

Methods: Patients with acute stroke and M1 MCA±intracranial internal carotid artery occlusion on baseline CTA were included. Baseline sCTA was assessed for phase of image acquisition.

Use of Noncontrast Computed Tomography and Computed Tomographic Perfusion in Predicting Intracerebral Hemorrhage After Intravenous Alteplase Therapy.

Background And Purpose: Intracerebral hemorrhage is a feared complication of intravenous alteplase therapy in patients with acute ischemic stroke. We explore the use of multimodal computed tomography in predicting this complication.

Methods: All patients were administered intravenous alteplase with/without intra-arterial therapy.

Permeability surface area product analysis in malignant brain edema prediction - A pilot study.

Background And Purpose: Using an extended CT perfusion acquisition (150s), we sought to determine the association between perfusion parameters and malignant edema after ischemic stroke.

Methods: Patients (from prospective study PROVE-IT, NCT02184936) with terminal internal carotid artery±proximal middle cerebral occlusion were involved. CTA was assessed for clot location and status of leptomeningeal collaterals.