http://www.nitrc.org/forum/forum.php?forum_id=6864 <table border="0" width="100%"><tr><td align="left"/><td align="right"><a href="https://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&amp;cmd=Link&amp;LinkName=pubmed_pubmed&amp;from_uid=27910126">Related Articles</a></td></tr></table> <p><b>Gradient-echo EPI using a high-degree shim insert coil at 7 T: Implications for BOLD fMRI.</b></p> <p>Magn Reson Med. 2016 Dec 1;:</p> <p>Authors: Kim T, Lee Y, Zhao T, Hetherington HP, Pan JW</p> <p>Abstract<br/> PURPOSE: To quantitatively assess the effects of high degree and order (1(st) -4(th+) ) relative to 1(st) -2(nd) degree B0 shimming at 7 Tesla (T) on gradient-echo echo planar imaging (GE-EPI) and blood-oxygen-level dependent (BOLD) activation.<br/> METHODS: Simulations and GE-EPI were performed at (2mm)(3) and (3mm)(3) resolution, evaluating the temporal signal-to-noise ratio (tSNR), transverse relaxivity ( R2*), BOLD % signal change and activated pixel counts in a breath-hold task.<br/> RESULTS: Comparing the 1(st) -4(th+) degree with 1(st) -2(nd) degree shimmed B0 maps generated spatially varying regions of Δ|B0|=|B01-2|-|B01-4+|. As binned in 10-Hz intervals, the two center Δ|B0 | (±10 Hz) bins maintained the B0 offset of 48.6% of gray-matter pixels. In the positive Δ|B0 | bins greater than 10 Hz, the 1(st) -4(th+) degree shimming improved the B0 offset in 41.1%; in negative Δ|B0 | bins less than -10 Hz, the offset worsened in 10.2% of the pixels. In the positive Δ|B0 | bins, we found variable but significant increases in BOLD sensitivity; the negative Δ|B0 | bins showed significant decreases. In the breath-hold studies, positive bins showed significantly increased activated pixel numbers (+5-29%), whereas negative bins showed -18 to 0% decline.<br/> CONCLUSION: 1(st) -4(th+) degree shimming maintained B0 homogeneity over central brain regions while improving most of the other regions, including the inferior frontal lobe. Magn Reson Med, 2016. © 2016 International Society for Magnetic Resonance in Medicine.<br/> </p><p>PMID: 27910126 [PubMed - as supplied by publisher]</p> en-us Copyright 2000-2026 NITRC OSI Wed, 06 May 2026 1:27:06 GMT http://blogs.law.harvard.edu/tech/rss NITRC RSS generator