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Acute blood–brain barrier opening in experimentally induced focal cerebral ischemia is preferentially identified by quantitative magnetization transfer imaging
Author(s) -
Knight Robert A.,
Nagesh Vijaya,
Nagaraja Tavarekere N.,
Ewing James R.,
Whitton Polly A.,
Bershad Eric,
Fagan Susan C.,
Fenstermacher Joseph D.
Publication year - 2005
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20630
Subject(s) - ischemia , magnetization transfer , blood–brain barrier , magnetic resonance imaging , nuclear magnetic resonance , chemistry , putamen , effective diffusion coefficient , medicine , pathology , nuclear medicine , central nervous system , radiology , physics
Pathologic changes in brain tissue during and after stroke may lead to injury of the blood–brain barrier (BBB) and subsequent hemorrhagic transformation (HT). In a rat model of HT, the apparent diffusion coefficient of water, cerebral blood flow, relaxation times, T 1 and T 2 , and magnetization transfer (MT) related parameters ( T 1sat , K for and the MT ratio) were repetitively measured during 3 h of focal ischemia and 2 h of reperfusion ( n = 8). Areas of BBB opening were identified by sequential assay of the transcapillary influx of Gd‐diethylenetriaminepentaacetic acid (Gd‐DTPA) by MRI and 14 C‐α‐aminoisobutyric acid (AIB) by quantitative autoradiography. Ischemia‐injured regions of interest were identified from the MRI data and divided into those with and without BBB opening. Of the several MRI parameters measured, the T 1sat in the caudate‐putamen and preoptic area during ischemia and the first 2 h of reperfusion correlated best with the regional pattern of BBB opening observed thereafter. These data suggest that an ipsilateral/contralateral T 1sat ratio > 1.6 demarcates leakage of small molecules such as Gd‐DTPA and AIB across the BBB. As to clinical relevance, the quantitation of MT parameters in acute stroke may enable the early detection of areas of BBB opening and potential HT. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.