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WE-G-217A-07: Increased MR Spatial Accuracy with Improved Gradient Nonlinearity and Magnet Inhomogeneity Correction.

K Hwang1, J Maier1, Z Slavens1

  • 1General Electric Healthcare, Waukesha, WI.

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|May 19, 2017
PubMed
Summary
This summary is machine-generated.

Improved magnetic resonance (MR) imaging spatial accuracy was achieved by using higher-degree spherical harmonic models for gradient nonlinearity and main magnetic field correction. This enhances MR scanner applications in therapy planning and image-guided procedures.

Keywords:
Classical spin modelsEncodingImage scannersMagnetic fieldsMagnetsMedical magnetic resonance imagingSpatial analysis

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Area of Science:

  • Medical Imaging
  • Physics
  • Engineering

Background:

  • Magnetic Resonance (MR) imaging systems are susceptible to spatial distortions.
  • Current correction methods often use limited-degree spherical harmonic models.
  • Enhanced accuracy is crucial for advanced MR applications.

Purpose of the Study:

  • To develop advanced distortion correction techniques for MR images.
  • To utilize higher-degree spherical harmonic models for gradient and main magnetic field correction.
  • To improve the spatial accuracy of MR images.

Main Methods:

  • Modeled gradient nonlinearities using first-order spherical harmonics up to the 9th degree.
  • Incorporated a main magnetic field model using zeroth-order spherical harmonics up to the 20th order.
  • Applied corrections to extended field-of-view (FOV) 3D FGRE phantom images.

Main Results:

  • Visual improvements in spatial accuracy were observed.
  • Wave-like distortions at phantom edges were significantly reduced.
  • Combined gradient and field homogeneity corrections minimized spatial errors.

Conclusions:

  • Accurate spherical harmonic models effectively correct major system-induced spatial errors in MR images.
  • Improved spatial accuracy supports widebore MR for therapy planning and percutaneous device guidance.
  • This advancement is beneficial for extended FOV imaging, including PET-MR systems.