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A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia.
McGarry, Bryony L; Jokivarsi, Kimmo T; Knight, Michael J; Grohn, Olli H J; Kauppinen, Risto A.
Afiliación
  • McGarry BL; School of Experimental Psychology and Clinical Research and Imaging Center Bristol, University of Bristol.
  • Jokivarsi KT; Department of Neurobiology, A.I. Virtanen Institute, University of Eastern Finland.
  • Knight MJ; School of Experimental Psychology and Clinical Research and Imaging Center Bristol, University of Bristol.
  • Grohn OHJ; Department of Neurobiology, A.I. Virtanen Institute, University of Eastern Finland.
  • Kauppinen RA; School of Experimental Psychology and Clinical Research and Imaging Center Bristol, University of Bristol; psrak@bristol.ac.uk.
J Vis Exp ; (127)2017 09 16.
Article en En | MEDLINE | ID: mdl-28994754
MRI provides a sensitive and specific imaging tool to detect acute ischemic stroke by means of a reduced diffusion coefficient of brain water. In a rat model of ischemic stroke, differences in quantitative T1 and T2 MRI relaxation times (qT1 and qT2) between the ischemic lesion (delineated by low diffusion) and the contralateral non-ischemic hemisphere increase with time from stroke onset. The time dependency of MRI relaxation time differences is heuristically described by a linear function and thus provides a simple estimate of stroke onset time. Additionally, the volumes of abnormal qT1 and qT2 within the ischemic lesion increase linearly with time providing a complementary method for stroke timing. A (semi)automated computer routine based on the quantified diffusion coefficient is presented to delineate acute ischemic stroke tissue in rat ischemia. This routine also determines hemispheric differences in qT1 and qT2 relaxation times and the location and volume of abnormal qT1 and qT2 voxels within the lesion. Uncertainties associated with onset time estimates of qT1 and qT2 MRI data vary from ± 25 min to ± 47 min for the first 5 hours of stroke. The most accurate onset time estimates can be obtained by quantifying the volume of overlapping abnormal qT1 and qT2 lesion volumes, termed 'Voverlap' (± 25 min) or by quantifying hemispheric differences in qT2 relaxation times only (± 28 min). Overall, qT2 derived parameters outperform those from qT1. The current MRI protocol is tested in the hyperacute phase of a permanent focal ischemia model, which may not be applicable to transient focal brain ischemia.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Encéfalo / Imagen por Resonancia Magnética / Isquemia Encefálica / Accidente Cerebrovascular Tipo de estudio: Prognostic_studies Límite: Animals Idioma: En Revista: J Vis Exp Año: 2017 Tipo del documento: Article Pais de publicación: Estados Unidos
Texto completo
Añadir a Mi BVS
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XML
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Encéfalo / Imagen por Resonancia Magnética / Isquemia Encefálica / Accidente Cerebrovascular Tipo de estudio: Prognostic_studies Límite: Animals Idioma: En Revista: J Vis Exp Año: 2017 Tipo del documento: Article Pais de publicación: Estados Unidos