Abstract
Abstract 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.
Keywords
Affiliated Institutions
Related Publications
Correction of physiologically induced global off‐resonance effects in dynamic echo‐planar and spiral functional imaging
Abstract In functional magnetic resonance imaging, a rapid method such as echo‐planar (EPI) or spiral is used to collect a dynamic series of images. These techniques are sensiti...
Tissue specificity of nonlinear dynamics in baseline fMRI
Abstract In this work, recent advances in the field of nonlinear dynamics (NLD) were applied to fMRI data to examine the spatio‐temporal properties of BOLD resting state fluctua...
Functional connectivity in the motor cortex of resting human brain using echo‐planar mri
Abstract An MRI time course of 512 echo‐planar images (EPI) in resting human brain obtained every 250 ms reveals fluctuations in signal intensity in each pixel that have a physi...
Functional Brain Mapping Using Magnetic Resonance Imaging: Signal Changes Accompanying Visual Stimulation
Easily detectable (5%-20%) transient increases in the intensity of water proton magnetic resonance (MR) signals in human primary visual cortex were observed during visual stimul...
Self‐navigated spiral fMRI: Interleaved versus single‐shot
Abstract This study compares the measured activation volumes in motor cortex as well as the fluctuation noise and off‐resonance characteristics for 1‐, 2‐, and 4‐shot spiral gra...
Publication Info
- Year
- 2001
- Type
- article
- Volume
- 46
- Issue
- 4
- Pages
- 631-637
- Citations
- 635
- Access
- Closed
External Links
Social Impact
Social media, news, blog, policy document mentions
Citation Metrics
Cite This
Identifiers
- DOI
- 10.1002/mrm.1240