http://www.nitrc.org/forum/forum.php?forum_id=4985 <table border="0" width="100%"><tr><td align="left"/></tr></table> <p><b>Reduced field of view imaging using a static second-order gradient for functional MRI applications.</b></p> <p>Magn Reson Med. 2015 Mar 25;</p> <p>Authors: Islam H, Glover GH</p> <p>Abstract<br/> PURPOSE: Imaging using reduced FOV excitation allows higher resolution or signal-to-noise ratio (SNR) per scan time but often requires long radiofrequency pulses. The goal of this study was to improve a recent reduced field of view (FOV) method that uses a second-order shim gradient to decrease pulse length and evaluate its use in functional MRI (fMRI) applications.<br/> THEORY AND METHODS: The method, which was initially limited to excite thin disc-shaped regions at the isocenter, was extended to excite thicker regions off the isocenter and produced accurate excitation profiles on a grid phantom. Visual stimulation fMRI scans were performed with full and reduced FOV. The resolution of the time series images and functional activation maps were assessed using the full-width half-maxima of the autocorrelation functions (FACFs) of the noise images and the activation map values, respectively.<br/> RESULTS: The resolution was higher in the reduced FOV time series images (4.1% ± 3.7% FACF reduction, P &lt; 0.02) and functional activation maps (3.1% ± 3.4% FACF reduction, P &lt; 0.01), but the SNR was lower (by 26.5% ± 16.9%). However, for a few subjects, the targeted region could not be localized to the reduced FOV due to the low Z2 gradient strength.<br/> CONCLUSION: The results of this study suggest that the proposed method is feasible, though it would benefit from a stronger gradient coil. Magn Reson Med, 2015. © 2015 Wiley Periodicals, Inc.<br/> </p><p>PMID: 25809723 [PubMed - as supplied by publisher]</p> en-us Copyright 2000-2026 NITRC OSI Fri, 01 May 2026 22:37:51 GMT http://blogs.law.harvard.edu/tech/rss NITRC RSS generator