TY  - JOUR
A1  - Schlamann, Marc
A1  - Yoon, Min-Suk
A1  - Maderwald, Stefan
A1  - Pietrzyk, Thomas
A1  - Bitz, Andreas
A1  - Gerwig, Marcus
A1  - Forsting, Michael
A1  - Ladd, Susanne C.
A1  - Ladd, Mark E.
A1  - Kastrup, Oliver
T1  - Short term effects of magnetic resonance imaging on excitability of the motor cortex at 1.5T and 7T
T2  - Academic Radiology
N2  - Rationale and Objectives
The increasing spread of high-field and ultra-high-field magnetic resonance imaging (MRI) scanners has encouraged new discussion of the safety aspects of MRI. Few studies have been published on possible cognitive effects of MRI examinations. The aim of this study was to examine whether changes are measurable after MRI examinations at 1.5 and 7 T by means of transcranial magnetic stimulation (TMS).

Materials and Methods
TMS was performed in 12 healthy, right-handed male volunteers. First the individual motor threshold was specified, and then the cortical silent period (SP) was measured. Subsequently, the volunteers were exposed to the 1.5-T MRI scanner for 63 minutes using standard sequences. The MRI examination was immediately followed by another TMS session. Fifteen minutes later, TMS was repeated. Four weeks later, the complete setting was repeated using a 7-T scanner. Control conditions included lying in the 1.5-T scanner for 63 minutes without scanning and lying in a separate room for 63 minutes. TMS was performed in the same way in each case. For statistical analysis, Wilcoxon's rank test was performed.

Results
Immediately after MRI exposure, the SP was highly significantly prolonged in all 12 subjects at 1.5 and 7 T. The motor threshold was significantly increased. Fifteen minutes after the examination, the measured value tended toward normal again. Control conditions revealed no significant differences.

Conclusion
MRI examinations lead to a transient and highly significant alteration in cortical excitability. This effect does not seem to depend on the strength of the static magnetic field.
Y1  - 2010
UR  - https://opus.bibliothek.fh-aachen.de/opus4/frontdoor/index/index/docId/8020
SN  - 1076-6332
VL  - 17
IS  - 3
SP  - 277
EP  - 281
PB  - Elsevier
CY  - Amsterdam
ER  -