Data quality in fMRI and simultaneous EEG-fMRI.
OBJECTIVE
To evaluate functional magnetic resonance imaging (fMRI) and simultaneous electroencephalography (EEG)-fMRI data quality in an organization using several magnetic resonance imaging (MRI) systems.


METHODS
Functional magnetic resonance imaging measurements were carried out twice with a uniform gel phantom on five different MRI systems with field strengths of 1.5 and 3.0 T. Several image quality parameters were measured with automatic analysis software. For simultaneous EEG-fMRI, data quality was evaluated on 3.0 T systems, and the phantom results were compared to data on human volunteers.


RESULTS
The fMRI quality parameters measured with different MRI systems were on an acceptable level. The presence of the EEG equipment caused superficial artifacts on the phantom image. The typical artifact depth was 15 mm, and no artifacts were observed in the brain area in the images of volunteers. Average signal-to-noise ratio (SNR) reduction in the phantom measurements was 15 %, a reduction of SNR similar to that observed in the human data. We also detected minor changes in the noise of the EEG signal during the phantom measurement.


CONCLUSIONS
The phantom proved valuable in the successful evaluation of the data quality of fMRI and EEG-fMRI. The results fell within acceptable limits. This study demonstrated a repeatable method to measure and follow up on the data quality of simultaneous EEG-fMRI.
HUS Medical Imaging Center, P.O. Box 340, 00029 HUS,, Helsinki, Finland, toni.ihalainen@hus.fi.
Toni
T
Ihalainen
Linda
L
Kuusela
Sampsa
S
Turunen
Sami
S
Heikkinen
Sauli
S
Savolainen
Outi
O
Sipilä
D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000295:instrumentation / Q000592:standards*; D000068598:Data Accuracy; D004569:Electroencephalography / Q000295:instrumentation / Q000592:standards*; D004867:Equipment Design; D005387:Finland; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods / Q000592:standards; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation / Q000379:methods / Q000592:standards; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000592:standards*; D064847:Multimodal Imaging / Q000295:instrumentation / Q000379:methods / Q000592:standards; D019047:Phantoms, Imaging / Q000592:standards*; D011785:Quality Assurance, Health Care / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity