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MRI of focal cerebral ischemia using 17 O‐labeled water
Author(s) -
de Crespigny A.J.,
D'Arceuil H.E.,
Engelhorn T.,
Moseley M.E.
Publication year - 2000
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 - 10.1002/1522-2594(200006)43:6<876::aid-mrm14>3.0.co;2-y
Subject(s) - ischemia , magnetic resonance imaging , cerebral ischaemia , nuclear magnetic resonance , medicine , radiology , cardiology , physics
This work presents a novel approach for quantifying low concentrations of H 2 17 O in vivo and explores its utility for assessing cerebral ischemia. Oxygen‐17 enriched water acts as a T 2 shortening contrast agent whose effect can be suppressed by decoupling at the 17 O frequency during TE interval in a spin‐echo MR image. Serial T 2 ‐weighted echo planar images were acquired in phantoms and rat brain with decoupler power alternated every eight images. The resulting periodic signal change (proportional to H 2 17 O concentration) was detected by cross‐correlating the square‐wave decoupler power timecourse with the signal intensity in each voxel. Natural abundance (0.037 atom%) images of H 2 17 O in rat brain were generated. The transverse relaxivity of H 2 17 O in brain was estimated, R 2 = 2.4 ± 0.5 s −1 (atom%) −1 . After bolus injection of 1 ml of 10 atom% H 2 17 O, brain H 2 17 O concentration was estimated at 0.06 ± 0.01 atom%. In the rat focal ischemia model, 17 O cross‐correlation maps compared well with diffusion and Gd‐DTPA perfusion images to indicate infarct location. Magn Reson Med 43:876–883, 2000. © 2000 Wiley‐Liss, Inc.