http://www.nitrc.org/forum/forum.php?forum_id=5903 <table border="0" width="100%"><tr><td align="left"/></tr></table> <p><b>Coil-to-coil physiological noise correlations and their impact on functional MRI time-series signal-to-noise ratio.</b></p> <p>Magn Reson Med. 2016 Jan 12;</p> <p>Authors: Triantafyllou C, Polimeni JR, Keil B, Wald LL</p> <p>Abstract<br/> PURPOSE: Physiological nuisance fluctuations ("physiological noise") are a major contribution to the time-series signal-to-noise ratio (tSNR) of functional imaging. While thermal noise correlations between array coil elements have a well-characterized effect on the image Signal to Noise Ratio (SNR0 ), the element-to-element covariance matrix of the time-series fluctuations has not yet been analyzed. We examine this effect with a goal of ultimately improving the combination of multichannel array data.<br/> THEORY AND METHODS: We extend the theoretical relationship between tSNR and SNR0 to include a time-series noise covariance matrix Ψt , distinct from the thermal noise covariance matrix Ψ0 , and compare its structure to Ψ0 and the signal coupling matrix SS(H) formed from the signal intensity vectors S.<br/> RESULTS: Inclusion of the measured time-series noise covariance matrix into the model relating tSNR and SNR0 improves the fit of experimental multichannel data and is shown to be distinct from Ψ0 or SS(H) .<br/> CONCLUSION: Time-series noise covariances in array coils are found to differ from Ψ0 and more surprisingly, from the signal coupling matrix SS(H) . Correct characterization of the time-series noise has implications for the analysis of time-series data and for improving the coil element combination process. Magn Reson Med, 2016. © 2016 Wiley Periodicals, Inc.<br/> </p><p>PMID: 26756964 [PubMed - as supplied by publisher]</p> en-us Copyright 2000-2026 NITRC OSI Mon, 04 May 2026 1:38:48 GMT http://blogs.law.harvard.edu/tech/rss NITRC RSS generator