ISMRM 23rd Annual Meeting & Exhibition • 30 May - 05 June 2015 • Toronto, Ontario, Canada

Scientific Session • Young Investigator Awards

Monday 1 June 2015

Room 701 A 

10:45 - 12:45


10:45 0029.   Selective magnetic resonance imaging of magnetic nanoparticles by Acoustically Induced Rotary Saturation (AIRS)
Bo Zhu1,2, Thomas Witzel1, Shan Jiang3, Susie Y. Huang1, Bruce R. Rosen1,4, and Lawrence L. Wald1,2
1Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States, 2Harvard-MIT Division of Health Sciences Technology, Massachusetts Institute of Technology, Cambridge, MA, United States, 3David H Koch Institute for Integrative Cancer Research, Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States, 4Department of Meridian & Acupuncture, Collaborating Center for Traditional Medicine, East-West Medi, Kyung Hee University, Seoul, Korea

The manual image interpretation process typically required to locate magnetic nanoparticle contrast agents from pre- and post-injection scans often results in ambiguous identifications. We present a resonant spin-lock acquisition technique to selectively image iron oxide contrast agents within an entirely post-injection paradigm, offering more certain localization of iron oxide presence for research and clinical studies. The ability to perform block-design experiments with the method’s rapidly modulatable agent contrast further enables quantitative statistical analysis, extending the robustness and flexibility of iron oxide nanoparticles as an investigative molecular imaging tool.

11:05 0030.   Spin Echoes in the Regime of Weak Dephasing
Jakob Assländer1, Steffen Glaser2, and Jürgen Hennig1
1Dept. of Radiology - Medical Physics, University Medical Center, Freiburg, Germany, 2Dept. of Chemistry, Technische Universität München, Germany

It is shown that it is possible to form spin echoes after a single excitation pulse, where the time between the end of the pulse and the echo is longer than the length of the pulse itself. This stands in contrast to Hahn's spin echo theory, where the length of the pulse sequence is at most equal to the time between the end of the composite pulse and the echo. A representative pulse is implemented into a FLASH sequence and proof-of-concept images show a reduction of off-resonance induced signal attenuation.

11:25 0031.   k-t FASTER: Acceleration of fMRI Data Acquisition using Low Rank Constraints - permission withheld
Mark Chiew1, Stephen M. Smith1, Peter J. Koopmans1, Nadine N. Graedel1, Thomas Blumensath1, and Karla L. Miller1
1FMRIB Centre, University of Oxford, Oxford, Oxfordshire, United Kingdom

FMRI data acquisition can benefit from improvements in sampling efficiency to provide richer spatial or temporal information. In this work, we propose a novel mechanism for accelerating FMRI data acquisition by leveraging the intrinsic spatio-temporal structure in FMRI datasets, namely that temporal information is shared across spatial locations. Our method, k-t FASTER (FMRI Accelerated in Space-time via Truncation of Effective Rank), is demonstrated on 4x accelerated data to recover resting state networks without using coil information. We also briefly highlight subsequent improvements using more sophisticated k-space trajectories to achieve up to 8.25x acceleration.

11:45 0032.   Free-Breathing Pediatric MRI with Nonrigid Motion Correction and Acceleration - permission withheld
Joseph Yitan Cheng1,2, Tao Zhang1,2, Nichanan Ruangwattanapaisarn3, Marcus T. Alley2, Martin Uecker4, John M. Pauly1, Michael Lustig4, and Shreyas S. Vasanawala2
1Electrical Engineering, Stanford University, Stanford, CA, United States, 2Radiology, Stanford University, Stanford, CA, United States, 3Ramathibodi Hospital, Mahidol University, Bangkok, Thailand, 4Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, United States

The goal of this work is to develop and assess motion correction techniques for free-breathing pediatric MRI. First, a variable-density sampling and radial-like phase-encode ordering scheme was developed for a 3D Cartesian acquisition. Second, intrinsic multichannel butterfly navigators were used to measure respiratory motion. Lastly, these estimates were applied for both motion-weighted data-consistency in an accelerated imaging reconstruction, and for nonrigid motion correction using a localized autofocusing framework. With IRB approval and informed consent, 22 pediatric patients were imaged, and representative features were evaluated. With the proposed methods, diagnosable high-resolution abdominal volumetric scans can be obtained from free-breathing acquisitions that are comparable to longer respiratory-gated scans.

12:05 0033.   In Vivo Visualization of Mesoscopic Anatomy of Healthy and Pathological Lymph Nodes Using 7T MRI: A Feasibility Study
Martin Thomas Freitag1, Mathies Breithaupt2, Moritz Berger2, Reiner Umathum2, Armin M. Nagel2, Jessica Hassel3, Mark E. Ladd2, Wolfhard Semmler2, Heinz-Peter Schlemmer4, and Bram Stieltjes4
1Section Quantitative Imaging Based Disease Characterization, German Cancer Research Center, Heidelberg, Baden-Wuerttemberg, Germany, 2Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany, 3Department of Dermatology, National Center for Tumor Diseases (NCT), University of Heidelberg, Heidelberg, Germany, 4Department of Radiology, German Cancer Research Center, Heidelberg, Baden-Wuerttemberg, Germany


12:25 0034.   Automatic and Quantitative Assessment of Total and Regional Muscle Tissue Volume using Multi-Atlas Segmentation - permission withheld
Anette Karlsson1,2, Johannes Rosander3, Joakim Tallberg2, Anders Grönqvist2,4, Magnus Borga1,2, and Olof Dahlqvist Leinhard2,5
1Department of Biomedical Engineering (IMT), Linköping University, Linköping, Sweden, Sweden, 2Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden, 3Advanced MR Analytics (AMRA) AB, Linköping, Sweden, 4Department of Radiation Physics and Department of Medical and Health Sciences, Linköping University, Linköping, Sweden, 5Department of Medical and Health Sciences (IMH), Linköping University, Linköping, Sweden

The purpose is to develop and demonstrate a rapid whole-body MRI method for automatic quantification of total and regional lean skeletal muscle volume. Quantitative water and fat separated image volumes of the whole body are manually segmented and used as atlases. The atlases are non-rigidly registered onto to a new image volume and the muscle groups are classified using a voting scheme. A leave-one-out approach with subjects scanned in a 1.5 T and a 3.0 T scanner is used for validation. The method quantifies the whole-body skeletal muscle volumes and the volumes of separate muscle groups independently of image resolution.