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Multispectral analysis of the temporal evolution of cerebral ischemia in the rat brain
Author(s) -
Carano Richard A.D.,
Li Fuhai,
Irie Katsumi,
Helmer Karl G.,
Silva Matthew D.,
Fisher Marc,
Sotak Christopher H.
Publication year - 2000
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/1522-2586(200012)12:6<842::aid-jmri7>3.0.co;2-5
Subject(s) - penumbra , medicine , lesion , ischemia , perfusion , multispectral image , magnetic resonance imaging , nuclear medicine , radiology , pathology , cardiology , computer science , artificial intelligence
A major difficulty in staging and predicting ischemic brain injury by magnetic resonance (MR) imaging is the time‐varying nature of the MR parameters within the ischemic lesion. A new multispectral (MS) approach is described to characterize cerebral ischemia in a time‐independent fashion. MS analysis of five MR parameters (mean diffusivity, diffusion anisotropy, T2, proton density, and perfusion) was employed to characterize the progression of ischemic lesion in the rat brain following 60 minutes of transient focal ischemia. k ‐Means (KM) and fuzzy c‐means (FCM) classification methods were employed to define the acute and subacute ischemic lesion. KM produced an estimate of lesion volume that was highly correlated with postmortem infarct volume, independent of the age of the lesion. Overall classification rates for KM exceeded FCM at acute and subacute time points as follows: KM, 90.5%, 94.4%, and 95.9%; FCM, 82.4%, 90.6%, and 82.6% (for 45 minutes, 180 minutes, and 24–120 hours post MCAO groups). MS analysis also offers a formal method of combining diffusion and perfusion parameters to provide an estimate of the ischemic penumbra (KM classification rate = 70.3%). J. Magn. Reson. Imaging 2000;12:842–858. © 2000 Wiley‐Liss, Inc.