| Autor: |
Nöth, Ulrike, Laufs, Helmut, Stoermer, Robert, Deichmann, Ralf |
| Zdroj: |
Journal of Magnetic Resonance Imaging; Mar2012, Vol. 35 Issue 3, p561-571, 11p |
| Abstrakt: |
Purpose: To describe heating effects to be expected in simultaneous electroencephalography (EEG) and magnetic resonance imaging (MRI) when deviating from the EEG manufacturer's instructions; to test which anatomical MRI sequences have a sufficiently low specific absorption rate (SAR) to be performed with the EEG equipment in place; and to suggest precautions to reduce the risk of heating. Materials and Methods: Heating was determined in vivo below eight EEG electrodes, using both head and body coil transmission and sequences covering the whole range of SAR values. Results: Head transmit coil: temperature increases were below 2.2°C for low SAR sequences, but reached 4.6°C (one subject, clavicle) for high SAR sequences; the equilibrium temperature Teq remained below 39°C. Body transmit coil: temperature increases were higher and more frequent over subjects and electrodes, with values below 2.6°C for low SAR sequences, reaching 6.9°C for high SAR sequences (T8 electrode) with Teq exceeding a critical level of 40°C. Conclusion: Anatomical imaging should be based on T1-weighted sequences (FLASH, MPRAGE, MDEFT) with an SAR below values for functional MRI sequences based on gradient echo planar imaging. Anatomical sequences with a high SAR can pose a significant risk, which is reduced by using head coil transmission. J. Magn. Reson. Imaging 2012;35:561-571. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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