Bo Zhu^1,2, Thomas Witzel¹, Shan Jiang³, Susie Y. Huang¹, Bruce R. Rosen^1,4, and Lawrence L. Wald^1,2
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.

Jakob Assländer¹, Steffen Glaser², and Jürgen Hennig^1
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.

Mark Chiew¹, Stephen M. Smith¹, Peter J. Koopmans¹, Nadine N. Graedel¹, Thomas Blumensath¹, and Karla L. Miller^1
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.

Joseph Yitan Cheng^1,2, Tao Zhang^1,2, Nichanan Ruangwattanapaisarn³, Marcus T. Alley², Martin Uecker⁴, John M. Pauly¹, Michael Lustig⁴, and Shreyas S. Vasanawala^2
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.

Martin Thomas Freitag¹, Mathies Breithaupt², Moritz Berger², Reiner Umathum², Armin M. Nagel², Jessica Hassel³, Mark E. Ladd², Wolfhard Semmler², Heinz-Peter Schlemmer⁴, and Bram Stieltjes^4
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

tba

Anette Karlsson^1,2, Johannes Rosander³, Joakim Tallberg², Anders Grönqvist^2,4, Magnus Borga^1,2, and Olof Dahlqvist Leinhard^2,5
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