Rapid RASER MRI

Angewandte Chemie International Edition, vol. 65, pp. e25699

Abstract

Abstract Conventional Magnetic Resonance Imaging (MRI) relies on high‐power Radio‐Frequency (RF) pulses to excite nuclear spins and in turn generate NMR signals. These pulses require large high‐power RF‐amplifiers and cause heat deposition in the tissue, which must be minimized for safety, presenting a growing problem when moving toward ever‐higher field MRI. An alternative to RF‐pulse excitation is self‐excitation of nuclear spins using Radiofrequency Amplification by Stimulated Emission of Radiation (RASER), where the nuclear spins undergo spontaneous transition, without RF excitation, from an over‐populated state to a ground state. Here, the feasibility of recording rapid proton RASER MRI images of pyrazine at low concentration (120 mM) with large matrix (128x128 pixels) in as little as 78 ms is demonstrated at 500 MHz (11.7 T). We also recorded a time‐series of images using a single bolus hyperpolarized pyrazine highlighting the feasibility of dynamic tracking. The demonstrated approach allows recording MRI scans without transmit‐receive electronics of the MRI scanner, which is highly desirable for portable MRI as well as the emerging field of hyperpolarized MRI using, e.g., HP protons, 129 Xe gas or HP 13 C labeled biomolecules as molecular tracers and imaging agents.

Authors 8

1. Sören Lehmkuhl corresponding

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute of Microstructure Technology Karlsruhe Institute of Technology Eggenstein‐Leopoldshafen 76344 Karlsruhe Germany

2. Simon Fleischer

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute of Microstructure Technology Karlsruhe Institute of Technology Eggenstein‐Leopoldshafen 76344 Karlsruhe Germany

3. Jing Yang

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute of Microstructure Technology Karlsruhe Institute of Technology Eggenstein‐Leopoldshafen 76344 Karlsruhe Germany

4. Eduard Y. Chekmenev

   Wayne State University · The Barbara Ann Karmanos Cancer Institute

   Affiliation as printed

   Department of Chemistry Integrative Biosciences Karmanos Cancer Institute Wayne State University Detroit Michigan 48202 USA

5. Thomas Theis

   North Carolina State University

   Affiliation as printed

   Department of Chemistry Department of Physics Comparative Medicine Institute North Carolina State University Raleigh North Carolina 27695–8204, 513 USA

6. Stephan Appelt Aachen Institute of Technical and Macromolecular Chemistry

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Institute of Technical and Macromolecular Chemistry RWTH Aachen University 52056 Aachen Germany

   Peter Grünberg Institute (PGI‐4) Integrated Computing Architectures (ICA) Forschungszentrum Jülich GmbH 52425 Jülich Germany

7. Jan Gerrit Korvink

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute of Microstructure Technology Karlsruhe Institute of Technology Eggenstein‐Leopoldshafen 76344 Karlsruhe Germany

8. Mazin Jouda corresponding

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute of Microstructure Technology Karlsruhe Institute of Technology Eggenstein‐Leopoldshafen 76344 Karlsruhe Germany