Room 250 BCEF

10:30 - 12:30

Moderators:

Blaine A. Chronik, Fraser J. L. Robb

Manoj M. Nimbalkar¹, Matthias Müller², Titus Lanz², Stephan G. Nekolla¹, Sibylle Ziegler¹, Rebekka Kraus¹, Sebastian Fürst¹, Axel Haase³, Markus Schwaiger¹, and Isabel Dregely^1
1Klinikum rechts der Isar, Technischen Universität München, München, Bayern, Germany, ²RAPID Biomedical GmbH, Rimpar, Germany,³Zentralinstituts für Medizintechnik, Technische Universität München, München, Bayern, Germany

Novel hybrid systems such as PET/MR can simultaneously provide metabolical and anatomical information in breast cancer imaging. Here we present design and implementation of a 16-channel breast RF coil optimized for simultaneous PET/MR (3T) systems. In phantom studies we found that the MR performance of the PET/MR coil was comparable to MR-only coils. Accurate PET quantification could be achieved with the PET/MR breast coil in the PET FOV by implementing a CT-based template-attenuation correction (AC) map of the coil to be combined with the MR-acquired phantom-AC map.

Yun-Jeong Stickle¹, Tae-Young Yang¹, Tom E. Zink¹, Sahil Bhatia¹, Victor Taracila¹, Fraser Robb¹, Bijay K. Shah², and David M. Goldhaber^2
1Engineering, GE Healthcare, Aurora, OH, United States, ²Engineering, GE Healthcare, Waukesha, WI, United States

A PET optimized 16- Element anterior array coil is described for acquiring high-sensitivity MR (Magnetic Resonance) images and good quality PET images of the torso and cardiac at 3 Tesla simultaneous PET/MR system. This anterior coil has been optimized to minimize the interference with gamma ray detection from the PET without scarifying MR image quality. In this study, we reduced the thickness of the rigid coil formers that consist of a Lexan 940 with the PET transparent material supports, optimized arrangement of components (internal cables, internal cable baluns, feedboards and decoupling boards) and introduced the new mechanical feedboard and decoupling housing design.

Christin Y. Sander^1,2, Avilash Cramer¹, Boris Keil¹, Azma Mareyam¹, Bruce R. Rosen^1,3, and Lawrence L. Wald^1,3
1A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States, ²Electrical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States, ³Health Sciences and Technology, Harvard-MIT, Cambridge, MA, United States

Simultaneous PET/MR imaging of non-human primates is challenging due to the lack of dedicated coils that are needed to target smaller brain volumes and allow for increased resolution without a loss in sensitivity. Moreover, the attenuation properties of coils are an important design parameter to ensure PET imaging with minimal artifacts. In this study, we developed two monkey coils of different sizes that minimized 511 keV attenuation and showed superior sensitivity and acceleration compared to the alternative use of a human head coil.

Sahil Bhatia¹, Gabriel Searles², Dmitriy Londarskiy², Tom E. Zink², Darren Gregan², Tae-Young Yang², Bijay Shah³, and Yun-Jeong Stickle^2
1GE Healthcare, Aurora, OH, United States, ²G.E. Healthcare, Aurora, OH, United States, ³G.E. Healthcare, Waukesha, WI, United States

MR-PET combines the advantages of MRI’s morphological imaging with excellent soft tissue contrast and PET’s functional imaging. Integrated MR-PET scanners offer several advantages over sequential scanners such as reduction in overall scan time and elimination of patient repositioning. In an integrated MR-PET system, phased array surface coils are directly in the PET field of view and attenuate positrons resulting in artifacts and poor quality PET images. This paper presents a head neck coil at 3T designed specifically to be transparent to PET positrons. Significant improvements in PET sensitivity loss are shown without loss in MR performance.

Christian Findeklee¹, Christoph Leussler¹, Daniel Wirtz¹, and Jochen Keupp^1
1Research Laboratories Hamburg, Philips Technologie GmbH, Hamburg, Germany

A PET compatible ¹H/¹⁹F surface coil was realized by an adjustable dual resonant inductive coupling loop. This concept enables convenient and accurate tuning and matching across a wide variety of different loading scenarios. In addition, the inductive coupling mechanism integrates a cable trap function. Furthermore, the stray field of the feeding loop is exactly the same at both operating frequencies. The coil was designed such that it is merely transparent for PET imaging.

Robert Grimm¹, Sebastian Fürst², Isabel Dregely², Stephan G. Nekolla², Sibylle Ziegler², Simon Bauer³, Dominik Nickel³, Berthold Kiefer³, Joachim Hornegger¹, Markus Schwaiger², and Kai Tobias Block^4
1Pattern Recognition Lab, FAU Erlangen-Nuremberg, Erlangen, Germany, ²Department of Nuclear Medicine, Technische Universität München, Munich, Germany, ³Siemens Healthcare, Erlangen, Germany, ⁴Department of Radiology, NYU Langone Medical Center, New York City, NY, United States

First in-vivo results of respiratory motion compensation in hybrid PET-MRI systems are presented. With the help of self-gated reconstructions of a 3D radial stack-of-stars GRE sequence, a motion model can be generated from the MR images. The derived self-gating signal also allows motion-binned PET reconstruction. The motion model is applied to warp the µ-map to different respiratory levels as well as to perform motion correction in the reconstructed PET images. The resulting images show better lesion delineation and sharpness of the liver dome compared to uncorrected reconstructions.

René Kartmann¹, Daniel H. Paulus¹, Bassim Aklan¹, Susanne Ziegler¹, Harald Braun¹, Bharath Navalpakkam¹, and Harald H. Quick^1
1Institute of Medical Phyics, Erlangen, Bavaria, Germany

Flexible RF surface coils used in simultaneous PET/MR imaging attenuate the PET signal and are currently not attenuation corrected. An algorithm is presented, which automatically integrates CT-based attenuation maps of flexible surface coils into PET attenuation correction. Registration is based on markers. Two phantoms are scanned with/out RF coils placed on top. Considerable local attenuation due to the presence of the coils was measured in regions close to the coils. The combined attenuation maps generated by the presented algorithm perform well concerning the attenuation correction of the coils. Furthermore, volunteer scans provide evidence that the algorithm is accurate and robust.

Mark Jason Hamamura¹, Seunghoon Ha², Werner W. Roeck¹, James W. Hugg³, Dirk Meier⁴, and Orhan Nalcioglu^1,5
1Tu & Yuen Center for Functional Onco-Imaging, University of California, Irvine, CA, United States, ²Tu & Yuen Center for Functional Onco-Imaging, University of California Irvine, Irvine, CA, United States, ³Gamma Medica, Inc., Northridge, CA, United States, ⁴Gamma Medica, Inc., Fornebu, Norway, ⁵Department of Cogno-Mechatronics, Pusan National University, Busan, Korea

We have developed a modular rotating gamma camera insert that has been designed for straightforward integration with existing MRI systems for simultaneous SPECT and MR imaging. Operation of the combined system was demonstrated through phantom and small animal imaging. Due to its versatility, we anticipate that this system can be utilized for a wide range of small-animal imaging applications.

Emilee Minalga¹, Robb Merrill¹, Nick Todd¹, Dennis L. Parker¹, and J. Rock Hadley^1
1Department of Radiology, University of Utah, Salt Lake City, UT, United States

This work describes the design of an open access 10-channel brain RF coil for magnetic resonance guided high intensity focused ultrasound. The coil was built to be compatible with a head stereotactic device and waterproof for use in a water tank. This coil uses capacitive decoupling of adjacent loops. The coil is evaluated for SNR performance, temperature imaging performance, and a comparison of anatomy scans. The coil was found to give better SNR over the body coil. This SNR increase translates to better anatomy imaging and temperature measurements.

Lukas Winter¹, Tessa van de Lindt¹, Celal Özerdem¹, Werner Hoffmann², Davide Santoro¹, Alexander Müller¹, Andreas Graessl¹, Reiner Seemann², Jaroslav Marek¹, and Thoralf Niendorf^1,3
1Berlin Ultrahigh Field Faciltiy (B.U.F.F.), Max-Delbrück Center for Molecular Medicine, Berlin, Germany, ²Metrology in Medicine, Physikalisch Technische Bundesanstalt, Berlin, Germany, ³Experimental and Clinical Research Center (ECRC), a joint cooperation between Charité Medical Faculty and Max-Delbrück Center for Molecular Medicine, Berlin, Germany

The concept of combining dedicated MR hardware for MR imaging, MR thermometry and targeted RF heating at 7.0T has been demonstrated recently. This study examines controlled RF induced heating at even higher frequencies (11.7T), to benefit from the sharpening and focusing abilities of a RF wavelength reduction. The presented antenna configurations both for 7.0T and 11.7T are suitable for MR imaging, MRTh and targeted RF-Heating. Temperature simulations in voxel models show, that a controlled generation of a hotspot in the human brain is feasible and the hotspot dimensions can be further reduced with an increase in frequency.