MR compatibility of EEG scalp electrodes at 4 tesla

✍ Scribed by Todd K. Stevens; John R. Ives; L. Martyn Klassen; Robert Bartha

• Book ID: 102905746
• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 693 KB
• Volume: 25
• Category: Article
• ISSN: 1053-1807
• DOI: 10.1002/jmri.20872

✦ Synopsis

Abstract

Purpose

To design and apply a method to quantitatively evaluate the MR compatibility of electroencephalographic (EEG) scalp electrodes based on pulse sequence‐independent metrics.

Materials and Methods

Three types of electrodes (constructed primarily of brass, silver, and conductive plastic, respectively) were tested. B~0~ field distortions, B~1~ shielding, and heat induction was measured in adjacent agarose and oil phantoms at 4 T. B~0~ field maps were corrected for distortions caused by the measurement apparatus and passive shim heating, and projections perpendicular to the surfaces of the electrodes were fit, generating cubic coefficients representing the electrode distortion severity. Signal loss in T~2~‐weighted images was used to determine B~1~ shielding by the electrodes. Temperature measurements were recorded during the application of a high‐power pulse sequence.

Results

Significantly different B~0~ distortions were observed in the three types of electrodes. The B~1~ shielding detected in all three electrodes is minimal for most human MRI, and no significant heating was detected in the electrodes or adjacent phantom.

Conclusion

The three types of electrodes were successfully differentiated in terms of MR compatibility based on pulse sequence‐independent B~0~ field distortions. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.