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Direct low-field MRI super-resolution using undersampled k-space

Daniel Tweneboah Anyimadu, Mohammed M. Abdelsamea, Ahmed Karam Eldaly

TL;DR

This work proposes a novel framework for reconstructing high-field MR like images directly from undersampled low-field k-space that employs a k-space dual channel U-Net that processes the real and imaginary components of undersampled k-space to restore missing frequency content.

Abstract

Low-field magnetic resonance imaging (MRI) provides affordable access to diagnostic imaging but suffers from prolonged acquisition and limited image quality. Accelerated imaging can be achieved with k-space undersampling, while super-resolution (SR) and image quality transfer (IQT) methods typically rely on spatial-domain post-processing. In this work, we propose a novel framework for reconstructing high-field MR like images directly from undersampled low-field k-space. Our approach employs a k-space dual channel U-Net that processes the real and imaginary components of undersampled k-space to restore missing frequency content. Experiments on low-field brain MRI demonstrate that our k-space-driven image enhancement consistently outperforms the counterpart spatial-domain method. Furthermore, reconstructions from undersampled k-space achieve image quality comparable to full k-space acquisitions. To the best of our knowledge, this is the first work that investigates low-field MRI SR/IQT directly from undersampled k-space.

Direct low-field MRI super-resolution using undersampled k-space

TL;DR

This work proposes a novel framework for reconstructing high-field MR like images directly from undersampled low-field k-space that employs a k-space dual channel U-Net that processes the real and imaginary components of undersampled k-space to restore missing frequency content.

Abstract

Low-field magnetic resonance imaging (MRI) provides affordable access to diagnostic imaging but suffers from prolonged acquisition and limited image quality. Accelerated imaging can be achieved with k-space undersampling, while super-resolution (SR) and image quality transfer (IQT) methods typically rely on spatial-domain post-processing. In this work, we propose a novel framework for reconstructing high-field MR like images directly from undersampled low-field k-space. Our approach employs a k-space dual channel U-Net that processes the real and imaginary components of undersampled k-space to restore missing frequency content. Experiments on low-field brain MRI demonstrate that our k-space-driven image enhancement consistently outperforms the counterpart spatial-domain method. Furthermore, reconstructions from undersampled k-space achieve image quality comparable to full k-space acquisitions. To the best of our knowledge, this is the first work that investigates low-field MRI SR/IQT directly from undersampled k-space.
Paper Structure (10 sections, 2 equations, 4 figures, 1 table)

This paper contains 10 sections, 2 equations, 4 figures, 1 table.

Figures (4)

  • Figure 1: K-space dual channel U-Net for LF-MRI SR/IQT using undersampled k-space.
  • Figure 2: HF-MR test images, and pseudo-radial and cartesian undersampling binary masks at 50% and 30% sampling rates.
  • Figure 3: Reconstruction results of the LF images, and IQT in the spatial and k-space domains, at different pseudo-radial under-sampling rates using two test images.
  • Figure 4: Absolute error maps between HF images in Fig. \ref{['fig:PRS_HFslices']}, and the reconstructions in Fig. \ref{['fig:PRS_IQTslices']} at different pseudo-radial under-sampling rates: $|\text{HF} - \text{LF}|$ in row 1, $|\text{HF} - \text{IQT-spatial}|$ in rows 2 and $|\text{HF} - \text{IQT-k-space}|$ in row 3.