ELECTRONIC POSTER - ismrm

14:30 3806. A 8 Channel TX/RX Decoupled Loop Array for Cardiac/body Imaging at 7T
Wolfgang Renz 1,2 , Tomasz Lindel, 23 , Matthias Dieringer 2,4 , Frank Seifert, 23 , Jeanette
Schulz-Menger, 2,5 , Thoralf Niendorf 2,4 , Bernd Ittermann, 23
1 Siemens AG, Erlangen, Germany; 2 Berlin Ultrahigh Field Facility, Max-Delbrueck-Center for Molecular
Medicine, Berlin, Germany; 3 Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany; 4 Experimental
and Clinical Research Center, Charite Campus Buch, Berlin, Germany; 5 CMR-Unit, Charite Campus Buch,
Berlin, Germany
The first steps in cardiac/body imaging at 7T have been reported. One of the challenges is a suitable TX coil concept, which adresses
the RF problems (B1 homogeneity, SAR) of body imaging at 300MHz. Traditional bodycoils seem not to be the right way, a coil array
enabling TX SENSE and B1 shimming seems to be more promising. We describe a 8-element TX/RX loop coil array with adjustable
capacitive decoupling. A prototype has been realised and tested. First imaging results in cardiac imaging are shown.
15:00 3807. Investigation of Element Designs and Construction of a Reconfigurable 8 Channel
Tx, 16 Channel Rx Torso Array for 7T
Ryan Brown 1 , Bernd Stoeckel 2 , Daniel K. Sodickson 1 , Graham C. Wiggins 1
1 Radiology, Center for Biomedical Imaging, NYU School of Medicine, New York, NY, United States;
2 Siemens Medical Solutions USA Inc., New York, NY, United States
7T torso imaging has been hindered by non-uniform B1+ distribution and inadequate B1+ in the center of the torso. Stripline coils
are the preferred method for RF excitation at 7T and have shown promise for torso imaging. Nevertheless, loop coils have not been
compared to striplines in the context of torso imaging. In this study, B1+ was measured using several single element prototype coils
and an array of stripline/loop combination coils. Results showed that the stripline array offers improved transmit efficiency near the
surface while loop coils may provide a marginal advantage at depth.
15:30 3808. Uniform Prostate Imaging and Spectroscopy at 7T: Comparison Between a Stripline
Array and an Endorectal Coil
Alexander Raaijmakers 1 , Bob van den Bergen 1 , Dennis Klomp 2 , Catalina Arteaga de
Castro 2 , Vincent Boer 2 , Hugo Kroeze 2 , Peter Luijten 2 , Jan Lagendijk 1 , Nico van den
Berg 1
1 Radiotherapy, UMC Utrecht, Utrecht, Netherlands; 2 Radiology, UMC Utrecht, Netherlands
In this study, we compare a 8-stripline coil array with a endorectal coil. FDTD simulations are performed to evaluate the SAR
deposition of both coils. Given the power restrictions due to these SAR levels, the suitability of the coils is tested for three common
imaging protocols for prostate cancer: a T1w image, a T2w image and MR spectroscopy. Results show that a surface coil array is
needed for T1w and T2w images, while the endorectal coil is needed for spectroscopy.
Tuesday 13:30-15:30 Computer 44
13:30 3809. B1 Shimming Using Passive Surface Coils in the Abdomen
Laura Sacolick 1 , Pekka T. Sipilae 1 , Mika W. Vogel 1 , Ileana Hancu 2
1 GE Global Research, Garching b. Munchen, Germany; 2 GE Global Research, Niskayuna, NY, United States
Here we present a simple approach for improving B1 homogeneity in the abdomen at 3 Tesla. 3D B1 maps were acquired from 6
subjects in the lower abdomen from the GE HDx whole body transmit coil. The B1 in the abdomen had very similar distributions in all
subjects studied. The average B1 distribution among these subjects was used to design and place two tuned passive loop coils to
couple to the transmit field and increase the B1 field in regions of low B1. One loop was tuned to 136.5 MHz and placed on the
anterior, and one tuned to 141.0 MHz was placed on the posterior abdomen. Significant improvement was found in the transmit B1
field homogeneity in subjects with the corrective coils.
14:00 3810. Reduction of B 1 Inhomogeneity Using B 1 Rectifying Fin at High Fields
Yukio Kaneko 1 , Hideta Habara 1 , Yoshihisa Soutome 1 , Yoshitaka Bito 1
1 Central Research Laboratory, Hitachi, Ltd., Kokubunji-shi, Tokyo, Japan
B 1 inhomogeneity in a human body increases as static magnetic field strength becomes higher, and various RF control methods have
been developed to reduce B 1 inhomogeneity. However, B 1 inhomogeneity still remains in some cases of abdominal imaging, and a
more effective method is necessary. We have proposed a new method using a B 1 rectifying finish combined with B 1 shimming. Both
electromagnetic simulation with phantom and experiments with a human abdomen were conducted, and we confirmed that the B 1
rectifying fin, used with B 1 shimming, was more effective in reducing B 1 inhomogeneity than B 1 shimming alone.