Related Experiment Video

Updated: Sep 23, 2025

Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
09:33

Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases

Published on: July 28, 2013

28.6K

Diffusion-relaxation scattered MR signal representation in a multi-parametric sequence

Fabian Bogusz1, Tomasz Pieciak2, Maryam Afzali3

  • 1AGH University of Science and Technology, Kraków, Poland.

Magnetic Resonance Imaging
|May 13, 2022
PubMed

Insights

This study introduces Relax-SHORE, a new method for magnetic resonance imaging (MRI) that accurately models diffusion and relaxation properties from limited data. It enables robust quantitative imaging in complex scenarios.

Area of Science:

  • Biomedical Imaging
  • Quantitative MRI
  • Diffusion MRI

Background:

  • Multi-parametric MRI acquisitions often involve scattered data with limited diffusion encoding.
  • Simultaneous modeling of diffusion and relaxation (T1, T2*) is challenging in such sparse datasets.
  • Accurate estimation of diffusion metrics and relaxation times is crucial for understanding tissue microstructure.

Purpose of the Study:

  • To develop a novel method for magnetic resonance imaging (MRI) signal representation that integrates diffusion and relaxation properties.
  • To enable accurate quantitative MRI from scattered multi-parametric acquisitions with limited diffusion information.
  • To retrieve diffusion indices and relaxation times simultaneously.

Main Methods:

  • Utilized a three-dimensional simple harmonic oscillator-based reconstruction and estimation (SHORE) representation for the diffusion signal.
  • Developed the Relax-SHORE technique to jointly estimate T1 and T2* relaxation times with diffusion parameters.
  • Applied the method to both in silico and in vivo diffusion-relaxation scattered MR data.

Main Results:

  • Demonstrated the accuracy of Relax-SHORE in reconstructing diffusion signals from scattered multi-parametric data.
  • Successfully resolved T1 and T2* relaxation times alongside diffusion properties.
  • Validated the method's performance on both simulated and real-world MRI datasets.

Conclusions:

  • Relax-SHORE provides an accurate and flexible approach for diffusion-relaxation MRI signal representation.
  • The method is effective even with sparse, scattered multi-parametric acquisitions.
  • Enables robust estimation of quantitative indices like generalized fractional anisotropy and return-to-the-origin probability.
Keywords:
BrainDiffusion MRIDiffusion-relaxationMicrostructureMulti-parametric sequence

More Related Videos

Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease09:30

Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease

Published on: December 18, 2016

19.7K
15N CPMG Relaxation Dispersion for the Investigation of Protein Conformational Dynamics on the µs-ms Timescale08:09

15N CPMG Relaxation Dispersion for the Investigation of Protein Conformational Dynamics on the µs-ms Timescale

Published on: April 19, 2021

5.4K

Related Concept Videos

NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences01:17

NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences

A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.
942
Atomic Nuclei: Types of Nuclear Relaxation01:28

Atomic Nuclei: Types of Nuclear Relaxation

Nuclear relaxation restores the equilibrium population imbalance and can occur via spin–lattice or spin–spin mechanisms, which are first-order exponential decay processes.
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers...
422
¹H NMR: Interpreting Distorted and Overlapping Signals01:02

¹H NMR: Interpreting Distorted and Overlapping Signals

Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.1K
¹H NMR Signal Multiplicity: Splitting Patterns01:13

¹H NMR Signal Multiplicity: Splitting Patterns

When protons A and X are coupled, their nuclear spin energy levels are slightly modified. This is because the energy required to excite proton A to a spin state parallel to proton X is slightly different from the energy required for it to become anti-parallel to spin X. Consequently, there are two possible excitation frequencies for A (A1 and A2), depending on the spin state of X, and vice versa. The mutual nature of coupling implies that the difference between frequencies A1 and A2, indicated...
5.4K
Atomic Nuclei: Nuclear Relaxation Processes01:23

Atomic Nuclei: Nuclear Relaxation Processes

In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis,  the precessing magnetic moments are randomly oriented around the z-axis.
735
NMR Spectrometers: Resolution and Error Correction01:14

NMR Spectrometers: Resolution and Error Correction

When magnetic nuclei in a sample achieve resonance and undergo relaxation, the signal detected in NMR is an approximately exponential free induction decay. Fourier transform of an exponential decay yields a Lorentzian peak in the frequency domain. Lorentzian peaks in an NMR spectrum are defined by their amplitude, full width at half maximum, and position, where the peak width is governed by the spin-spin relaxation time alone. In real experiments, however, the applied magnetic field is rendered...
786