Magnetic Resonance Line Shape of Water as a Probe of the Structure of Biological Tissue

• Applicant: Professor Dr. Valerij Kiselev, Ph.D.
• Subject Area: Medical Physics, Biomedical Technology
• Term: from 2012 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 222108118

• Final Report Year: 2018

Final Report Abstract

In this project, two new windows for accessing the microscopic structure of heterogenous magnetic materials were opened for the users of NMR and MRI technologies. Namely, they are the long-time behavior of the transverse relaxation and the specific precession frequency of nuclear spins measurable in an NMR sample or an MRI imaging voxel. Accessing the microstructural properties can be considered as a super-resolution in MRI, since the addressed microstructure, such as properties of biological cells are two–three orders of magnitude finer than the achievable special resolution of MRI. The result on the transverse relaxation is novel with implications outside the MRI community, in particular, it is the first observation of the recently proposed maximally random jammed state of hard spheres without any microscopic imaging methods, which demonstrates the power of microscopic MRI outside the MRI community. While such a link was not anticipated within the MRI community, the results on the precession frequency came to the focus of intensive ongoing discussion with implications for recently developed MRI modalities (SWI, QSM, STI). The achieved results clarify the situation and, hopefully, help reaching a consensus within the MRI community.

Publications

• 2013. Characterizing microstructure by a time-dependent transverse relaxation rate. Proc. 21st Annual Meeting of ISMRM, 2013, p. 2590
  Alexander Ruh, Philipp Emerich, Dmitry S. Novikov, and Valerij G. Kiselev
  
• 2015. Observation of time-dependent transverse relaxation rate due to mesoscopic magnetic structure. Proc. 22rd Annual Meeting of ISMRM, 2014, p. 3124
  Philipp Emerich, Alexander Ruh, Harald Scherer, Dmitry S. Novikov, and Valerij G. Kiselev
  
• 2015. Lorentz cavity field in media with magnetic structure. Proc. 23rd Annual Meeting of ISMRM, 2015, p. 1700
  Alexander Ruh and Valerij G. Kiselev
  
• Time-dependent transverse relaxation reveals statistics of structural organization in microbead samples. Proc. 23rd Annual Meeting of ISMRM, 2015, p. 1667
  Alexander Ruh, Philipp Emerich, Harald Scherer, Dmitry S. Novikov, and Valerij G. Kiselev
  
• 2017. Larmor frequency shift in anisotropic heterogeneous media. Proc. 25th Annual Meeting of ISMRM, 2017, p. 467
  Alexander Ruh and Valerij G. Kiselev
  
• The Larmor frequency shift in magnetically heterogeneous media depends on their mesoscopic structure. Magnetic Resonance in Medicine 79 (2018) 1101–1110
  Alexander Ruh, Harald Scherer, and Valerij G. Kiselev
  (See online at https://doi.org/10.1002/mrm.26753)