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Encoding of electrophysiology and other signals in MR images
Author(s) -
Hanson Lars G.,
Lund Torben E.,
Hanson Christian G.
Publication year - 2007
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.20906
Subject(s) - scanner , computer science , computer vision , artificial intelligence , oversampling , signal (programming language) , encoding (memory) , electrooculography , synchronization (alternating current) , channel (broadcasting) , bandwidth (computing) , eye movement , telecommunications , programming language
Purpose To develop a gradient insensitive, generic technique for recording of non‐MR signals by use of surplus scanner bandwidth. Materials and Methods Relatively simple battery driven hardware is used to transform one or more signals into radio waves detectable by the MR scanner. Similar to the “magstripe” technique used for encoding of soundtracks in motion pictures, the electrical signals are in this way encoded as artifacts appearing in the MR images or spectra outside the region of interest. The encoded signals are subsequently reconstructed from the signal recorded by the scanner. Results Electrophysiological (EP) eye and heart muscular recording (electrooculography [EOG] and electrocardiography [ECG]) during fast echo planar imaging (EPI) is demonstrated with an expandable, modular 8‐channel prototype implementation. The gradient artifacts that would normally be dominating EOG are largely eliminated. Conclusion The method provides relatively inexpensive sampling with inherent microsecond synchronization and it reduces gradient artifacts in physiological recordings significantly. When oversampling is employed, the method is compatible with all MR reconstruction and postprocessing techniques. J. Magn. Reson. Imaging 2007;25:1059–1066. © 2007 Wiley‐Liss, Inc.