Real-time functional magnetic resonance imaging

• Published in: Magnetic resonance in medicine Vol. 33; no. 2; p. 230
• Main Authors: Cox, R W, Jesmanowicz, A, Hyde, J S
• Format: Journal Article
• Language: English
• Published: United States 01-02-1995
• Subjects: Algorithms; Analog-Digital Conversion; Brain - anatomy & histology; Brain - physiology; Color; Computer Systems; Data Display; Echo-Planar Imaging - methods; Echo-Planar Imaging - statistics & numerical data; Fingers - physiology; Humans; Image Processing, Computer-Assisted - methods; Image Processing, Computer-Assisted - statistics & numerical data; Likelihood Functions; Magnetic Resonance Imaging - methods; Magnetic Resonance Imaging - statistics & numerical data; Models, Statistical; Motor Skills - physiology; Time Factors
• ISSN: 0740-3194
• DOI: 10.1002/mrm.1910330213

A recursive algorithm suitable for functional magnetic resonance imaging (FMRI) calculations is presented. The correlation coefficient of a time course of images with a reference time series, with the mean and any linear trend projected out, may be computed with 22 operations per voxel, per image; the storage overhead is four numbers per voxel. A statistical model for the FMRI signal is presented, and thresholds for the correlation coefficient are derived from it. Selected images from the first real-time functional neuroimaging experiment (at 3 Tesla) are presented. Using a 50-MHz workstation equipped with a 14-bit analog-to-digital converter, each echo planar image was acquired, reconstructed, correlated, thresholded, and displayed in pseudocolor (highlighting active regions in the brain) within 500 ms of the RF pulse.