A novel method for quantifying scanner instability in fMRI

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

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)1053-1061
Number of pages9
JournalMagnetic Resonance in Medicine
Issue number4
StatePublished - Apr 2011

All Science Journal Classification (ASJC) codes

  • Radiology Nuclear Medicine and imaging


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