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Physiological noise in oxygenation‐sensitive magnetic resonance imaging
Author(s) -
Krüger Gunnar,
Glover Gary H.
Publication year - 2001
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.1240
Subject(s) - communication noise , nuclear magnetic resonance , noise (video) , oxygenation , magnetic resonance imaging , white matter , physics , blood oxygenation , spiral (railway) , chemistry , functional magnetic resonance imaging , biology , neuroscience , medicine , computer science , mathematics , artificial intelligence , mathematical analysis , philosophy , linguistics , image (mathematics) , radiology
The physiological noise in the resting brain, which arises from fluctuations in metabolic‐linked brain physiology and subtle brain pulsations, was investigated in six healthy volunteers using oxygenation‐sensitive dual‐echo spiral MRI at 3.0 T. In contrast to the system and thermal noise, the physiological noise demonstrates a signal strength dependency and, unique to the metabolic‐linked noise, an echo‐time dependency. Variations of the MR signal strength by changing the flip angle and echo time allowed separation of the different noise components and revealed that the physiological noise at 3.0 T (1) exceeds other noise sources and (2) is significantly greater in cortical gray matter than in white matter regions. The SNR in oxygenation‐sensitive MRI is predicted to saturate at higher fields, suggesting that noise measurements of the resting brain at 3.0 T and higher may provide a sensitive probe of functional information. Magn Reson Med 46:631–637, 2001. © 2001 Wiley‐Liss, Inc.