MRI Technique Estimates Brain Tissue at Risk of Infarct from Stroke

The new imaging technique yields an estimate of the final level of brain tissues at risk of infarction for acute stroke patients. This new technique is derived from an unprecedented analysis of magnetic resonance imaging (MRI) data.

The application, called the NEURiNFARCT technique, results from the collaboration of the Cognitive Neuroscience and Brain Imaging Laboratory of the French National Center for Scientific Research (CNRS; Paris), and the Acute Stroke Center of the Pitié-Salpêtrière General Hospital (Paris France). The results of Dr. Charlotte Rosso and her coauthors study, which were published online in November 18, 2008, on the Radiology journal web site, demonstrate how this new technique may help predict within minutes the severity of stroke infarcts using a conventional clinical MR scanner.

Ischemic stroke is caused by clogged blood vessels, thereby putting target organs at risk of cellular death. NEURiNFARCT identifies the ischemic penumbra, a region subject to rapid developments within a few hours after the onset of a stroke, and conducive to severe irreversible brain lesions. Contrary to the zone of initial infarct, the penumbra region may be saved during the early acute phase of stroke, and therefore, the risk of subsequent deficits for the patients may be reduced--using thrombolytic medication, although this treatment has its share of possible secondary hemorrhagic complications. Early evaluation of the severity of stroke could therefore help assist the critical fast therapeutic decision-making process.

This challenge has fostered the research project from which NEURiNFARCT has originated. Existing MRI-based approaches necessitated the injection of a contrast agent; something NEURiNFARCT could make obsolete as the new technique only necessitates basic routine diffusion MR image sequences. The diffusion data measure the mobility of water molecules in tissues, which is considerably reduced in the core of the infarct lesion and to a much lesser extent, in the ischemic penumbra region. Sight identification of these alterations of the MRI data in the region at risk of infarction is impossible. The new approach, therefore, proposes an image analysis approach based on a model of the ongoing infarct growth in brain tissues.

The results from the study demonstrated that NEURiNFARCT performs at least as well as alternative approaches using perfusion techniques in MRI or computed tomography (CT) scanners, though these latter are conditioned to the delicate intravenous injection of a contrast agent. NEURiNFARCT has the secondary advantages in the context of acute emergency care that it is an automatic and standard procedure.

This new approach, according to the investigators, is likely to significantly contribute to rapid therapeutic decision-making and to faster throughput in the assessment of new drug molecules by the pharmaceutical industry. A NEURiNFARCT software prototype is currently contributing to ongoing research studies on treatments against evolving brain infarcts. This is of critical importance in the context of stroke, which concerns as many patients as Alzheimer and Parkinson's diseases. The NEURiNFARCT technique has been internationally patented.


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French National Center for Scientific Research