Reducing correlated noise in fMRI data

✍ Scribed by Jacco A. de Zwart; Peter van Gelderen; Masaki Fukunaga; Jeff H. Duyn

• Book ID: 102955122
• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 506 KB
• Volume: 59
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.21507

✦ Synopsis

Abstract

The sensitivity of functional MRI (fMRI) in detecting neuronal activation is dependent on the relative levels of signal and noise in the time‐series data. The temporal noise level within a single voxel is generally substantially higher than the intrinsic NMR (thermal) noise, and the noise is often correlated between voxels. This work introduces and evaluates a method that allows fMRI sensitivity improvement by reduction of these correlated noise sources. The method allows model‐free estimation of the correlated noise from brain regions not activated by the functional paradigm using a short (1–2 min) reference scan. A single regressor representing this noise‐source estimate is added to the design matrix used in the data analysis. Results obtained from five volunteers show an average t‐score improvement of 11.3% and a 24.2% increase in the size of the activated area. Magn Reson Med 59:939–945, 2008. © 2008 Wiley‐Liss, Inc.