Fourier transform temporal diffusion spectroscopy

Franciszek Hennel; Hannes Dillinger; Jochen Leupold; Klaas P Pruessmann

doi:10.1016/j.jmr.2023.107401

Fourier transform temporal diffusion spectroscopy

J Magn Reson. 2023 Mar:348:107401. doi: 10.1016/j.jmr.2023.107401. Epub 2023 Feb 9.

Authors

Franciszek Hennel¹, Hannes Dillinger², Jochen Leupold³, Klaas P Pruessmann²

Affiliations

¹ Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland. Electronic address: hennel@biomed.ee.ethz.ch.
² Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland.
³ Division of Medical Physics, Department of Diagnostic and Interventional Radiology, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

PMID: 36774713
DOI: 10.1016/j.jmr.2023.107401

Abstract

Temporal diffusion spectroscopy (TDS) currently uses the oscillating gradient spin echo (OGSE) experiment to measure the spectral density of translational velocity autocorrelation at single frequencies. Due to timing restrictions imposed by the transverse relaxation, the frequency selectivity and the sampling density of OGSE are limited, especially at low frequencies. We propose to overcome this problem by adopting the principles of Fourier transform spectroscopy. The new method of Fourier transform TDS (FTDS) uses two broadband gradient waveforms with different relative delays to make the spin echo attenuation sensitive to a broad range of diffusion frequencies with different harmonic modulations and calculates the spectrum by discrete Fourier transform. The method was validated by a measurement of diffusion spectra in highly restrictive tissues of a celery stalk and provided results consistent with OGSE, however, on a denser frequency grid.

Keywords: Diffusion NMR; Diffusion Spectroscopy; Fourier transform spectroscopy; OGSE; Restricted diffusion.