18 17 11 5 191 document 11 article.pdf application/pdf 539800 2010-04-02 00:05:22 http://eprints.drcmr.dk/18/1/article.pdf 18 1 application/pdf en public

article.pdf

accepted http://eprints.org/relation/hasVolatileVersion /id/document/57 http://eprints.org/relation/haspreviewThumbnailVersion /id/document/57 http://eprints.org/relation/hasVersion /id/document/57 http://eprints.org/relation/hasVolatileVersion /id/document/112 http://eprints.org/relation/hasVersion /id/document/112 http://eprints.org/relation/hasIndexCodesVersion /id/document/112 archive 1 disk0/00/00/00/18 2008-06-28 20:46:37 2010-04-02 00:05:21 2008-06-28 21:11:00 article show larsh@drcmr.dk 0 Hanson Lars G larsh@drcmr.dk Lund Torben E Hanson Christian G pub E01x370x376x300 E01x370x350x500x200 E05x047 drcmr public 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. 2007 completed Journal of Magnetic Resonance Imaging : JMRI 25 5 Wiley InterScience 1059-66 TRUE 1053-1807 http://dx.doi.org/10.1002/jmri.20906 http://www.mriware.com/ author 1. Ives JR, Warach S, Schmitt F, Edelman RR, Schomer DL. Monitoring the patient's EEG during echo planar MRI. Electroencephalogr Clin Neurophysiol 1993;87(6):417–20. 2. Salek-Haddadi A, Friston KJ, Lemieux L, Fish DR. Studying spontaneous EEG activity with fMRI. Brain Res Brain Res Rev 2003;43(1):110–33. 3. Anami K, Mori T, Tanaka F, Kawagoe Y, Okamoto J, Yarita M, Ohnishi T, Yumoto M, Matsuda H, Saitoh O. Stepping stone sampling for retrieving artifact-free electroencephalogram during functional magnetic resonance imaging. Neuroimage 2003;19(2 Pt 1):281–95. 4. Cohen MS, Goldman R, Stern J, Engel J. Simultaneous EEG and fMRI made easy. In Proc. of Human Brain Mapping Annual Meeting. 2001; 6. 5. Allen PJ, Josephs O, Turner R. A method for removing imaging artifact from continuous EEG recorded during functional MRI. Neuroimage 2000;12(2):230–9. 6. Beauchamp MS. Detection of eye movements from fMRI data. Magn Reson Med 2003; 49(2):376–80. 7. Allen PJ, Polizzi G, Krakow K, Fish DR, Lemieux L. Identication of EEG events in the MR scanner: The problem of pulse artifact and a method for its subtraction. Neuroimage 1998; 8(3):229–39. 8. Hoffmann A, Jager L, Werhahn KJ, Jaschke M, Noachtar S, Reiser M. Electroencephalography during functional echo-planar imaging: Detection of epileptic spikes using post-processing methods. Magn Reson Med 2000;44(5):791–8. 9. DICOM Standards Committee, Working Group 1. Supplement 30: Waveform interchange. 2000. 10. Press W, Teukolsky S, Vetterling W, Flannery B. Numerical Recipes in C (The Art of Scientic Computing). Cambridge University Press, 1992. 11. Moody GB. Spectral analysis of heart rate without resampling. Computers in Cardiology 1993; 20:715–718. 12. Qi Y, Minka TP, Picard RW. Bayesian spectrum estimation of unevenly sampled nonstationary data, 2002. MIT Media Lab Technical Report Vismod-TR-556. 13. Bonmassar G, Purdon PL, Jaaskelainen IP, Chiappa K, Solo V, Brown EN, Belliveau JW. Motion and ballistocardiogram artifact removal for interleaved recording of EEG and eps during MRI. Neuroimage 2002;16(4):1127–41. 14. Negishi M, Abildgaard M, Nixon T, Constable RT. Removal of time-varying gradient artifacts from EEG data acquired during continuous fMRI. Clin Neurophysiol 2004;115(9):2181–92.