MRI Research Today is a free monthly online journal that collates and summarizes the latest research about MRI, including details on magnetic resonance imaging, neuroimaging, brain tumors.

Time is brain: is MRI the clock?

Neumann-Haefelin T, Steinmetz H

Department of Neurology, Goethe-University Frankfurt, Frankfurt, Germany. tnh@rz.uni-frankfurt.de

PURPOSE OF REVIEW: MRI is increasingly used as the primary imaging modality in acute stroke, since it allows treatment based on individual pathophysiology rather than strict time windows. RECENT FINDINGS: PET studies have confirmed that regions with disturbed diffusion frequently indicate irreversible tissue damage, although they may in part be viable. The mismatch between a larger perfusion deficit and a smaller diffusion abnormality contains both critically hypoperfused regions as well as oligemic regions. Although mismatch is thus not perfect, recent prospective trials have convincingly shown that mismatch patients treated with revascularization therapies benefit from reperfusion, while patients without mismatch do not. This is particularly important for patients presenting beyond the first three hours. In addition, several studies have investigated MRI as a tool to assess the risk of thrombolytic treatment. Parameters reflecting severe ischemia, blood-brain barrier damage and preexisting small-vessel disease emerge as risk factors for intracerebral hemorrhage, while microbleeds are not clearly associated with an increased risk. SUMMARY: Based on data from prospective trials, the mismatch concept is an acceptable method to identify patients who benefit from recanalization therapies. The concept, however, still needs to be further improved and standard definitions are required before widespread use can be recommended.

Published 10 July 2007 in Curr Opin Neurol, 20(4): 410-6.
Full-text of this article is available online (may require subscription).

© 2005-2008 MRI Research Today. All Rights Reserved.