ELECTRONIC POSTER - ismrm

14:30 3886. Safety in Simultaneous EEG-FMRI: Temperature Changes of the Electrodes in a
Phantom and a Volunteer Study
Linda Kuusela 1,2 , Sampsa Turunen 1,3 , Outi Sipilä 1
1 HUS Helsinki Medical Imaging Center, Helsinki (HUS), Finland; 2 Department of Physics, Univeristy of
Helsinki, Helsinki, Finland; 3 Department of Physics, University of Helsinki, Helsinki, Finland
An EEG-fMRI protocol is being developed at the Helsinki Medical Imaging Center to aid in the pre-surgical evaluation of patients
with epilepsy. The purpose of this study was to study the heating of the electrodes with our protocol. Phantom and volunteer studies
were performed, by measuring the temperatures of the EEG-electrodes in a 3T MRI scanner. A maximum temperature increase of 4.1
and 1.0º C was observed for a T2-TSE sequence in the phantom and the volunteer study, respectively. The temperature increase was
found to be within safe limits to perform simultaneous EEG-fMRI patient studies with our protocol.
15:00 3887. Magnetic and RF Characterization of Stents Using Magnetic Resonance Imaging
Karl-Heinz Herrmann 1 , Anne Rösler 2,3 , Andreas Hansch 4 , Stefan OR Pfleiderer 5 , Jürgen
R. Reichenbach 2
1 Medical Physics Group, Department of Diagnostic and Interventional Radiology, Jena University Hospital ,
Jena, Thüringen, Germany; 2 Medical Physics Group, Department of Diagnostic and Interventional Radiology,
Jena University Hospital, Jena, Thüringen, Germany; 3 Department of Medical Engineering and Biotechnology,
University of Applied Sciences, Jena, Germany; 4 Department of Diagnostic and Interventional Radiology, Jena
University Hospital, Jena, Germany; 5 Central Institute for Diagnostics and Nuclear Medicine, Clinical Center
Bremerhaven-Reinkenheide, Germany
While some manufacturers provide MR compatibility certifications for stents, the actual imaging artifacts after implantation may still
vary widely. To assess and predict imaging artifacts produced by implanted stents, characterization of both, magnetic and rf
properties, is necessary. In this study effective susceptibilities and maps of the flip angle distribution were determined from MR
imaging data for different stent types.
15:30 3888. A FMRI Compatible Thumb Actuator for Stroke Patients
Ewa Piatkowska-Janko 1 , Grzegorz Goworek 1 , Artur Handke 2 , Tomasz Wolak 3 , Maciej
Krawczyk 4 , Piotr Bogorodzki 1
1 Institute of Radioelectronics, Warsaw University of Technology, Warsaw, Poland; 2 Wroclaw University of
Technology, Poland; 3 Institute of Physiology and Pathology of Hearing, Poland; 4 Institute of Psychiatry and
Neurology, Poland
In order to overcome limitations of fMRI for disabled patients we propose a pneumatical mechanical system helping them in fMRI
motor stimulation paradigms. Results for group of healthy volunteers right and left handed were preset. Preliminary results for patient
monitoring during rehabilitation time were also presented.
Tuesday 13:30-15:30 Computer 49
13:30 3889. Safety in EEG-MRI: Heating Beneath EEG Scalp Electrodes for Different RF
Transmit Coils
Ulrike Nöth 1 , Helmut Laufs, 1,2 , Robert Stoermer 3 , Ralf Deichmann 1
1 Brain Imaging Center (BIC), Goethe University Frankfurt am Main, Frankfurt am Main, Germany;
2 Department of Neurology, Goethe University Frankfurt am Main, Frankfurt am Main, Germany; 3 Brain
Products GmbH, Gilching, Germany
The heating beneath eight EEG scalp electrodes during simultaneous EEG-MRI acquisition was measured in vivo, using various MR
sequences covering a wide range of SAR values. RF transmission was performed with a head and a body coil in comparison.
Temperature increases beneath the electrodes were stronger and more frequent for the body coil, and fitted equilibrium temperatures
reached the critical level of 41°C for high SAR sequences. This is of special interest as many scanners are not routinely equipped with
a head transmit coil.
14:00 3890. The Compatibility of Temporary Pacemaker Leads with Magnetic Resonance
Imaging – an Ex Vivo Tissue Study
Reinhard Rzanny 1 , Andreas Hansch 2 , Alexander Pfeil 3 , Alexander Gussew 1 , Stefanie
Drobnik 4 , Jürgen R. Reichenbach 5
1 Medical Physics Group, Department of Diagnostic and Interventional Radiology, Jena University Hospital,
Jena, Germany; 2 Department of Diagnostic and Interventional Radiology, Jena University Hospital, Jena,
Germany; 3 Department of Internal Medicine III, Jena University Hospital, Jena, Germany; 4 Department of
Cardiothoracic Surgery, Jena University Hospital, Jena, Germany; 5 Medical Physics Group, Department of
Diagnostic and Interventional Radiology, Jena University Hospital, Jena, Germany
The presence of pacemaker leads is considered to be a safety contraindication for MRI. To measure heating effects at the tip of
temporary pacemaker leads, the frequency shift of water was estimated by single voxel 1H-MRS. The temperature dependence of the
water frequency in the myocardial tissue was estimated in prior preliminary experiments during 3 warming and cooling cycles of a