ISMRM 21st Annual Meeting & Exhibition 20-26 April 2013 Salt Lake City, Utah, USA

New Systems & Probes
Monday 22 April 2013
Room 155 EF  16:30 - 18:30 Moderators: Daniel K. Sodickson, Jason P. Stockmann

16:30 0131.   A Separated Transmit-Only, Receive-Only Array for Body Imaging at 7T with Automated Tuning and Matching Capabilities
Carl Snyder1, Lance DelaBarre1, Aaron T. Hess2, Chris Rodgers2, Mattew Robson2, and University of Minnesota University of Minnesota Vaughan1
1University of Minnesota, Minneapolis, MN, United States, 2University of Oxford, Oxford, United Kingdom

Describe below is a novel 16-channel TEM transmit-Only array used with a 32-channel receive-only loop array for body imaging at 7T. Additionally, and more importantly, we describe an electromechanical method for automating the tuning and matching process for the 16 transmit elements using piezoelectric actuators. Automation of the tuning and matching procedure took, on average 50s and with an average S11 greater than 20dB. Following tuning and matching the array successfully imaged the human torso.

16:42 0132.   A Novel Flexible Flex Cable Antenna (FFCA) for Foot MR Imaging
Hongyang Yuan1, Qunzhi Chen2, Yu Wang2, Wenchao Cai3, Xiaoying Wang2,3, Jue Zhang1,2, and Jing Fang1,2
1College of Engineering, Peking University, Beijing, China, 2Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China, 3Department of Radiology, Peking University First Hospital, Beijing, China

In this study, a novel flexible antenna, which is consisted of a flex cable and tuning/matching box, was developed for human foot MR imaging. Experimental results show that compared to conventional phase array coils, the FFCA have a higher SNR and better magnetic field homogeneity, and it can be easily designed for individual foot shape with higher fill factor. Meanwhile, the feasibility of FFCA has been validated by phantom and healthy human foot experiments. In the near future, it is believed that as a flexible antenna, the FFCA can be applied for hand or other unusual shape of human body.

16:54 0133.   
Screen Printed Flexible 2-Channel Receive Coil Array
Joseph R. Corea1, Ana Claudia Arias1, Anita Flynn1, Greig C. Scott2, Peter Shin3, and Michael Lustig1
1EECS, UC Berkeley, Berkeley, California, United States, 2EE, Stanford University, Stanford, California, United States, 3EE, UC San Francisco, San Fransisco, California, United States

Taking advantage of recent advances in printed electronics, we have created a flexible 2-channel receive coil array. This array was fabricated from solution using screen-printing, a high volume manufacturing technique. The entire array is highly flexible and allows for a new level of conformity to the patient. We discuss the performance of the array and compare the printed components to traditional ceramic components under various bending conditions. We also demonstrate major steps toward clinical usability with the first phantom and in-vivo imaging results.

17:06 0134.   
Development of a Catheter-Mounted Cardiac RF Coil for Temperature Imaging in Atrial Fibrillation Treatment
Nelly A. Volland1,2, Robb Merrill1, J. Rock Hadley1,2, and Dennis L. Parker1,2
1Ucair/ Radiology, University of Utah, Salt Lake City, UT, United States, 2CARMA, University of Utah, Salt Lake City, UT, United States

Purpose: An expandable catheter-mounted local RF cardiac coil was developed and evaluated. Methods: Elastic fiberglass filaments with predetermined curvature allowed the flexible inductive coil loop to fold and unfold in and out of a sheath. A microcoaxial cable electrically connected the inductive loop to the receiver circuit board through the sheath. For expansion, the support arms were pushed out of the 11 Fr catheter sheath until the loop was fully extended. Results and conclusion: The prototype of an expandable catheter-mounted local cardiac coil was successfully constructed and used to acquire MR images at 3T in a saline phantom.

17:18 0135.   High-Temperature Superconducting Radiofrequency Probe for MRI Applications Operated Below Ambient Pressure in a Simple Liquid-Nitrogen Cryostat
Simon Auguste Lambert1, Marie Poirier-Quinot1, Jean-christophe Ginefri2, and Luc Darrasse1
1CRB3- INSERM U773, Univ Paris Diderot, Sorbonne Paris Cit, Clichy, France, 2CRB3- INSERM U773, Univ Paris-Sud, Clichy, France

Small high-temperature superconducting coils improve the signal-to-noise ratio (SNR) but their use is limited by the large degradation of their electrical properties due to the static magnetic field, depending both on the coil orientation relative to B0 and on the cooling temperature (THTS). In this work, by decreasing THTS from 83K to 69K, SNR improvement has been demonstrated, degree of freedom in the coil orientation has been added. Moreover THTS control has appeared to be an easy way to retune the HTS coil to the NMR frequency. Additional THTS decrease would be beneficial for imaging small animals at higher fields.

17:30 0136.   
MR Microimaging Using a High Tc Superconducting Bulk Magnet with Compressed Sensing
Daiki Tamada1,2, Takashi Nakamura1,2, and Katsumi Kose1,2
1Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki, Japan, 2RIKEN, Wako, Saitama, Japan

A high critical temperature (Tc) superconducting bulk magnet is a promising magnet for magnetic resonance (MR) microimaging since it produces a strong (up to 17 T) and very stable (0.018 T/hour) magnetic field with a small installation space. However, the major application for the bulk magnet is now limited to MR microimaging of small objects because the room temperature bore diameter is limited. In such case, a long signal averaging time is required to achieve sufficient signal-to-noise ratio due to the small voxel volume.In this study, we demonstrated usefulness of compressed sensing in MR microimaging using the high Tc bulk magnet.

17:42 0137.   A Lightweight, Portable MRI Brain Scanner Based on a Rotating Halbach Magnet
Clarissa Zimmerman Cooley1,2, Jason P. Stockmann2,3, Brandon Dean Armstrong2,3, Matthew S. Rosen2,3, and Lawrence L. Wald2
1Electrical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States, 2Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States, 3Department of Physics, Harvard University, Cambridge, MA, United States

A lightweight brain scanner based on a rotating permanent-magnet Halbach array is constructed and tested in phantom imaging. As the magnet is rotated around the object, the multipolar static field inhomogeneity creates generalized projections. The image is reconstructed using an iterative algebraic reconstruction technique based on knowledge of the field map. We show 2D phantom images containing aliasing artifacts similar to radial PatLoc images, which share the multipolar encoding field. These artifacts are greatly reduced through parallel imaging methods, which further reduce streaking and other residual artifacts while improving resolution.

17:54 0138.   
Target Field Based RF Phase Gradient Transmit Array for 3D TRASE MRI
Jesse Bellec1, Scott B. King1,2, Chen-Yi Liu1, and Christopher P. Bidinosti3
1Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada, 2National Research Council of Canada, Winnipeg, Manitoba, Canada, 3Physics, University of Winnipeg, Winnipeg, Manitoba, Canada

Transmit array spatial encoding (TRASE) is novel gradient-free imaging technique relying on Tx RF phase gradients to spatially encode the transverse magnetization. Ideal phase gradients have uniform magnitudes and linear phase gradients. To perform a 3D TRASE MRI experiment, 2 distinct phase gradients are required for each dimension. A target field approach was used to design a five coil Tx array that can be driven to produce a set six RF phase gradients necessary for 3D TRASE MRI at 3T.

18:06 0139.   
An Open Source Mobile NMR Relaxometry Platform
Michael Twieg1, Matthew J. Riffe2, Natalia Gudino2, and Mark A. Griswold1,3
1Dept. of Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, OH, United States, 2Dept. of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, 3Dept. of Radiology, Case Western Reserve University, Cleveland, OH, United States

We present an improved mobile and low-cost NMR hardware platform aimed for use in simple NMR relaxometry experiments. The platform includes all necessary hardware, with the exception of the NMR probe itself, in a single enclosure. The platform is versatile, allowing for operation across a wide frequency range and with various NMR probes. The flexible system firmware allows for many relaxometry experiments, including measurement of T1, T2, ρ0, and self diffusion coefficient (D). The total cost of the system, neglecting the host computer, is less than $750. Documentation on the platform is open source and available online.

18:18 0140.   Magnetic Particle Imaging for Safe Angiography and Stem Cell Tracking
Emine U. Saritas1, Patrick W. Goodwill1, Justin J. Konkle1, Laura R. Croft1, Kuan Lu1, Bo Zheng1, and Steven M. Conolly1,2
1Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States, 2Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, United States

Magnetic Particle Imaging (MPI) is a new imaging modality that re-uses FDA-approved superparamagnetic iron oxide (SPIO) nanoparticle contrast agents in a new imaging scanner (i.e., not an MRI scanner) [1-3]. The MPI method has ideal SNR, penetration, linearity and contrast, and is completely non-invasive. Moreover, compared to iodine and gadolinium, the SPIO contrast agents are much safer for patients with Chronic Kidney Disease (CKD). This work describes our state-of-the-art MPI scanners and MPIs potential for applications such as angiography and quantitative cell tracking.