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Whole‐brain three‐dimensional T2‐weighted BOLD functional magnetic resonance imaging at 7 Tesla
Author(s) -
Hua Jun,
Qin Qin,
Zijl Peter C.M.,
Pekar James J.,
Jones Craig K.
Publication year - 2014
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.25055
Subject(s) - contrast (vision) , spin echo , nuclear magnetic resonance , gradient echo , temporal resolution , functional magnetic resonance imaging , physics , echo time , echo (communications protocol) , magnetic resonance imaging , blood oxygenation , t2 weighted , computer science , artificial intelligence , neuroscience , optics , medicine , psychology , computer network , radiology
Purpose A new acquisition scheme for T2‐weighted spin‐echo BOLD fMRI is introduced. Methods It uses a T2‐preparation module to induce blood‐oxygenation‐level‐dependent (BOLD) contrast, followed by a single‐shot three‐dimensional (3D) fast gradient‐echo readout with short echo time (TE). It differs from most spin‐echo BOLD sequences in that BOLD contrast is generated before the readout, which eliminates the “dead time” due to long TE required for T2 contrast, and substantially improves acquisition efficiency. This approach, termed “3D T2prep‐GRE,” was implemented at 7 Tesla (T) with a typical spatial (2.5 × 2.5 × 2.5 mm 3 ) and temporal (TR = 2.3 s) resolution for functional MRI (fMRI) and whole‐brain coverage (55 slices), and compared with the widely used 2D spin‐echo EPI sequence. Results In fMRI experiments of simultaneous visual/motor activities, 3D T2prep‐GRE showed minimal distortion and little signal dropout across the whole brain. Its lower power deposition allowed greater spatial coverage (55 versus 17 slices with identical TR, resolution and power level), temporal SNR (60% higher) and CNR (35% higher) efficiency than 2D spin‐echo EPI. It also showed smaller T2* contamination. Conclusion This approach is expected to be useful for ultra‐high field fMRI, especially for regions near air cavities. The concept of using T2‐preparation to generate BOLD contrast can be combined with many other sequences at any field strength. Magn Reson Med 72:1530–1540, 2014. © 2013 Wiley Periodicals, Inc.