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Comparison of T 2 *‐weighted sequences for functional MRI
Author(s) -
Hu Xiaoping,
Erhard Peter,
Le Tuang Huu,
Kim SeongGi,
Me Ravi,
Andersen Peter,
Adriany Gregor,
Strupp John P.,
Uǧurbil Kâmil
Publication year - 1995
Publication title -
international journal of imaging systems and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.359
H-Index - 47
eISSN - 1098-1098
pISSN - 0899-9457
DOI - 10.1002/ima.1850060208
Subject(s) - echo planar imaging , nuclear magnetic resonance , spiral (railway) , physics , flash (photography) , sensitivity (control systems) , gradient echo , magnetic resonance imaging , materials science , mathematics , optics , mathematical analysis , medicine , electronic engineering , radiology , engineering
Several sequences, including conventional gradient‐echo sequence (e.g., FLASH), gradient‐echo echo‐planar imaging (EPI), T 2 * prepared ultrafast gradient echo technique (TurboFLASH), and T 2 *‐weighted spiral sequence, are currently used for T 2 *‐weighted functional magnetic resonance imaging. This paper presents a comparison of FLASH, gradient‐echo EPI, and T 2 *‐prepared TurboFLASH. Experimental results have demonstrated that these sequences have different susceptibility to physiologic fluctuation, which is likely the dominant source of noise. EPI images exhibit the lowest relative fluctuation, while images obtained by FLASH and TurboFLASH, respectively, display similar relative fluctuation. Functional maps generated using these sequences are comparable but exhibit different sensitivity to activation from large vessels. Consequently, interpretation of activation results from various maps should take into account the difference in the sequences.