Reproducibility of functional MRI localization within the human somatosensory cortex

✍ Scribed by Rishma Vidyasagar; Laura M. Parkes

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 268 KB
• Volume: 34
• Category: Article
• ISSN: 1053-1807
• DOI: 10.1002/jmri.22758

✦ Synopsis

Abstract

Purpose:

To evaluate the effect of fMRI localization approaches and region size on the reproducibility of digit localization in the human somatosensory cortex.

Materials and Methods:

Vibrotactile stimulation was applied to digits 2 and 4 producing cortical activation sites relating to each digit. Thirteen subjects were scanned twice on separate occasions in a 3 Tesla scanner using a voxel size of 2 mm. Regions of activity were thresholded to different sizes varying from 50 to 1000 voxels. Three measures of position were acquired from these regions: center of gravity (COG), center co‐ordinate and peak voxel. To account for registration errors, Euclidean distance between the two digits was computed. Reproducibility was determined in terms of the 95% confidence interval for individual position in X, Y, and Z and also the distance between the two digit locations.

Results:

Region size of 200 most significant voxels was shown to have the best reproducibility. Center co‐ordinate proved to be the most precise form of localizing activity with a 95% CI of 2.1 mm, 2.6 mm, and 3.1 mm in the X, Y, and Z axes. Euclidean distance between the center co‐ordinates of the two digit activation sites was shown to be a reliable means of overcoming registration errors with a 95% CI of 1.7 mm.

Conclusion:

This study shows a high level of reproducibility for fMRI localization in the somatosensory system. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.