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Related Experiment Video

Updated: Nov 16, 2025

Deriving the Time Course of Glutamate Clearance with a Deconvolution Analysis of Astrocytic Transporter Currents
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Non-Cartesian k-space trajectory calculation based on concurrent reading of the gradient amplifiers' output currents.

Jürgen Rahmer1, Ingo Schmale1, Peter Mazurkewitz1

  • 1Philips Research, Hamburg, Germany.

Magnetic Resonance in Medicine
|February 19, 2021
PubMed
Summary

Accurate magnetic field dynamics in non-Cartesian MRI are determined by measuring gradient amplifier output currents. This novel method improves image reconstruction quality by better accounting for gradient imperfections.

Keywords:
MRIcurrent measurementgradient amplifiergradient impulse response functionnon-Cartesianultrashort TE

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Area of Science:

  • Magnetic Resonance Imaging (MRI)
  • Medical Physics
  • Biomedical Engineering

Background:

  • Non-Cartesian imaging sequences require precise knowledge of encoding field gradient dynamics for high-quality image reconstruction.
  • Inaccurate field dynamics lead to artifacts and reduced image fidelity in MRI.

Purpose of the Study:

  • To develop a measurement-based method for accurately determining magnetic field dynamics during non-Cartesian MRI acquisition.
  • To improve k-space trajectory calculation and subsequent image reconstruction quality.

Main Methods:

  • Measuring gradient amplifier output currents concurrently with MRI data acquisition.
  • Calculating actual dynamic field evolution using a measured current-to-field impulse response function.
  • Integrating gradient field evolution to derive accurate k-space trajectories.

Main Results:

  • The proposed current-based approach demonstrated slightly improved image quality in spiral and ultrashort TE phantom imaging.
  • This improvement was attributed to better modeling of eddy current effects and amplifier nonlinearities.
  • The method offers a robust, measurement-based alternative to conventional model-based trajectory calculations.

Conclusions:

  • A novel, purely measurement-based method for trajectory calculation in non-Cartesian MRI is presented.
  • This approach effectively mitigates gradient amplifier imperfections with minimal hardware requirements.
  • The technique provides a robust alternative to model-based methods, enhancing MRI image reconstruction accuracy.