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Ultrafast in vivo diffusion imaging of stroke at 21.1 T by spatiotemporal encoding
Author(s) -
Leftin Avigdor,
Rosenberg Jens T.,
Solomon Eddy,
Calixto Bejarano Fabian,
Grant Samuel C.,
Frydman Lucio
Publication year - 2015
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.25271
Subject(s) - echo planar imaging , diffusion mri , diffusion imaging , magnetic resonance imaging , spin echo , nuclear magnetic resonance , stroke (engine) , effective diffusion coefficient , diffusion , single shot , nuclear medicine , medicine , physics , computer science , radiology , optics , thermodynamics
Purpose This study quantifies in vivo ischemic stroke brain injuries in rats using ultrahigh‐field single‐scan MRI methods to assess variations in apparent diffusion coefficients (ADCs). Methods Magnitude and diffusion‐weighted spatiotemporally encoded imaging sequences were implemented on a 21.1 T imaging system, and compared with spin‐echo and echo‐planar imaging diffusion‐weighted imaging strategies. ADC maps were calculated and used to evaluate the sequences according to the statistical comparisons of the ipsilateral and contralateral ADC measurements at 24, 48, and 72 h poststroke. Results Susceptibility artifacts resulting from normative anatomy and pathological stroke conditions were particularly intense at 21.1 T. These artifacts strongly distorted single‐shot diffusion‐weighted echo‐planar imaging experiments, but were reduced in four‐segment interleaved echo‐planar imaging acquisitions. By contrast, nonsegmented diffusion‐weighted spatiotemporally encoded images were largely immune to field‐dependent artifacts. Effects of stroke were apparent in both magnitude images and ADC maps of all sequences. When stroke recovery was followed by ADC variations, spatiotemporally encoded, echo‐planar imaging, and spin‐echo acquisitions revealed statistically significant increase in ADCs. Conclusions Consideration of experiment duration, image quality, and mapped ADC values provided by spatiotemporally encoded demonstrates that this single‐shot acquisition is a method of choice for high‐throughput, ultrahigh‐field in vivo stroke quantification. Magn Reson Med 73:1483–1489, 2015. © 2014 Wiley Periodicals, Inc.