Magnetic Resonance Imaging Criteria for Thrombolysis in Acute Cerebral Infarct

Abstract

Background and Purpose-Magnetic resonance imaging (MRI) selection of stroke patients eligible for thrombolytic therapy is an emerging application. Although the efficacy of therapy within 3 hours after onset of symptoms with intravenous (IV) tissue plasminogen activator (tPA) has been proven for patients selected with computed tomography (CT), no randomized, double-blinded MRI trial has been published yet. Summary of Review-MRI screening of acute stroke patients before thrombolytic therapy is performed in some cerebrovascular centers. In contrast to the CT trials, MRI pilot studies demonstrate benefit of therapy up to 6 hours after onset of symptoms. This article reviews the literature that has lead to current controlled MRI-based thrombolysis trials. We examined the MRI criteria applied in 5 stroke centers. Along with the personal views of clinicians at these centers, the survey reveals a variety of clinical and MRI technical aspects that must be further investigated: the therapeutic consequence of microbleeds, the use of magnetic resonance angiography, dynamic time windows, and others. Conclusion-MRI is an established application in acute evaluation of stroke patients and may suit as a brain clock, replacing the currently used epidemiological time clock when deciding whether to initiate thrombolytic therapy. MRI criteria for thrombolytic therapy are applied in some cerebrovascular centers, but the results of ongoing clinical trials must be awaited before it is possible to reach consensus. (Stroke. 2005;36:388-397.)

Bench to Bedside: The Quest for Quality in Experimental Stroke Research

“…A clear therapeutic benefit of stroke units has been demonstrated (Langhorne and Dennis, 2004;Alberts et al, 2005;Stroke Unit Trialists' Collaboration, 1997;Indredavik et al, 1999;Drummond et al, 2005). Advanced diagnostic imaging of stroke is now widely available, and includes early measures of damage (DWI) as well as blood perfusion (magnetic resonance (MR)-angiography, MR perfusion, computed tomography perfusion; Warach, 2003;Hjort et al, 2005). In addition, stroke trial design has come of age.…”

Early Identification of Potentially Salvageable Tissue with MRI-Based Predictive Algorithms after Experimental Ischemic Stroke

“…2,6,7 However, lack of standard postprocessing procedures and threshold values may compromise robust characterization of a 'perfusion-diffusion mismatch', 3,8 and volumetric analysis may obscure and oversimplify the complex and heterogeneous status of the affected tissue. 7,9,10 This mismatch area may therefore overestimate the actual tissue area at risk, 5,11,12 as well as exclude injured tissue that is potentially salvageable. 13 The complex relation between multiple pathophysiologic factors involved in stroke lesion progression may be better caught and described using multiparametric imaging-based statistical algorithms.…”

Use of heparin in neurointervention: a review of the literature

“…It is necessary to detect microbleeds (MBs) or hemorrhagic transformation (HT) early and accurately, and to institute rapid treatment decisionmaking according to neuroimaging findings to prevent development of a hemorrhageprone state and improve neurologic recovery. (24)(25)(26) Other complications derived from the use of heparin, is the heparin-related ICH, which is rare and data are sparse regarding appropriate treatment. One reasonable approach would be to reverse heparin with IV protamine sulfate at a dose of 1 mg to 1.5 mg per 100 units of heparin with a maximum dose of 50 mg. (27,28) Heparin-induced thrombocytopenia (HIT) is a rare but important adverse event for heparin anticoagulation.…”