A novel method for quantifying scanner instability in fMRI

✍ Scribed by Douglas N. Greve; Bryon A. Mueller; Thomas Liu; Jessica A. Turner; James Voyvodic; Elizabeth Yetter; Michele Diaz; Gregory McCarthy; Stuart Wallace; Brian J. Roach; Judy M. Ford; Daniel H. Mathalon; Vince D. Calhoun; Cynthia G. Wible; Gregory G. Brown; Steven G. Potkin; Gary Glover

• Book ID: 102534054
• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 440 KB
• Volume: 65
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.22691

✦ Synopsis

Abstract

A method was developed to quantify the effect of scanner instability on functional MRI data by comparing the instability noise to endogenous noise present when scanning a human. The instability noise was computed from agar phantom data collected with two flip angles, allowing for a separation of the instability from the background noise. This method was used on human data collected at four 3 T scanners, allowing the physiological noise level to be extracted from the data. In a “well‐operating” scanner, the instability noise is generally less than 10% of physiological noise in white matter and only about 2% of physiological noise in cortex. This indicates that instability in a well‐operating scanner adds very little noise to functional MRI results. This new method allows researchers to make informed decisions about the maximum instability level a scanner can have before it is taken off line for maintenance or rejected from a multisite consortium. This method also provides information about the background noise, which is generally larger in magnitude than the instability noise. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.