Image-based estimation method for field inhomogeneity in brain echo-planar images with geometric distortion using k-space textures

Seiji Kumazawa, Takashi Yoshiura, Hiroshi Honda

Research output: Contribution to journalArticle

Abstract

Echo-planar imaging (EPI) can suffer from geometrical distortion due to magnetic field inhomogeneity. To correct the geometric distortions in EPI, a magnetic field map is used. Our purpose was to develop a novel image-based method for estimating the field inhomogeneity map from the distorted EPI image and T1-weighted image of the brain using k-space textures. Based on magnetic resonance imaging physics, our method synthesizes the distorted image to match the measured EPI image through the generating process of EPI image by updating the estimated field inhomogeneity map. The estimation process was performed to minimize the cost function, which was defined by the synthesized EPI image and the measured EPI image with geometric distortion, using an iterative conjugate gradient algorithm. The proposed method was applied to simulation and human data. To evaluate the performance of the proposed method quantitatively, we used the normalized root mean square error (NRMSE) between the ground truth and the results estimated by our proposed method. In simulation data, the values of the NRMSE between the ground truth and the estimated field inhomogeneity map were <0.08. In both simulation and human data, the estimated EPI images were very similar to input EPI images, and the NRMSE values between them were <0.09. The results of the simulated and human data demonstrated that our method produced a reasonable estimation of the field inhomogeneity map. The estimated map could be used for distortion correction in EPI images.

Original languageEnglish
Pages (from-to)142-152
Number of pages11
JournalConcepts in Magnetic Resonance Part B: Magnetic Resonance Engineering
Volume45
Issue number3
DOIs
Publication statusPublished - Jan 1 2015

Fingerprint

Echo-Planar Imaging
brain
Brain
echoes
inhomogeneity
textures
Textures
Imaging techniques
root-mean-square errors
Mean square error
ground truth
Magnetic Fields
Magnetic fields
Physics
data simulation
Magnetic resonance
magnetic fields
Cost functions
magnetic resonance
Magnetic Resonance Imaging

All Science Journal Classification (ASJC) codes

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging
  • Spectroscopy
  • Physical and Theoretical Chemistry

Cite this

Image-based estimation method for field inhomogeneity in brain echo-planar images with geometric distortion using k-space textures. / Kumazawa, Seiji; Yoshiura, Takashi; Honda, Hiroshi.

In: Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering, Vol. 45, No. 3, 01.01.2015, p. 142-152.

Research output: Contribution to journalArticle

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