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Updated: Jun 23, 2026
Registered Bioimaging of Nanomaterials for Diagnostic and Therapeutic Monitoring
Published on: December 9, 2010
High resolution diffusion-weighted imaging using readout-segmented echo-planar imaging, parallel imaging and a
David A Porter1, Robin M Heidemann
1Siemens AG, Healthcare Sector, Erlangen, Germany. david.a.porter@siemens.com
Abstract:
Single-shot echo-planar imaging (EPI) is well established as the method of choice for clinical, diffusion-weighted imaging with MRI because of its low sensitivity to the motion-induced phase errors that occur during diffusion sensitization of the MR signal. However, the method is prone to artifacts due to susceptibility changes at tissue interfaces and has a limited spatial resolution. The introduction of parallel imaging techniques, such as GRAPPA (GeneRalized Autocalibrating Partially Parallel Acquisitions), has reduced these problems, but there are still significant limitations, particularly at higher field strengths, such as 3 Tesla (T), which are increasingly being used for routine clinical imaging. This study describes how the combination of readout-segmented EPI and parallel imaging can be used to address these issues by generating high-resolution, diffusion-weighted images at 1.5T and 3T with a significant reduction in susceptibility artifact compared with the single-shot case. The technique uses data from a 2D navigator acquisition to perform a nonlinear phase correction and to control the real-time reacquisition of unusable data that cannot be corrected. Measurements on healthy volunteers demonstrate that this approach provides a robust correction for motion-induced phase artifact and allows scan times that are suitable for routine clinical application.
Insights
This study introduces a new MRI technique combining segmented EPI and parallel imaging to improve diffusion-weighted imaging. It significantly reduces artifacts and enhances resolution at 1.5T and 3T for clinical applications.
Area of Science:
- Magnetic Resonance Imaging (MRI)
- Medical Physics
- Radiology
Background:
- Single-shot echo-planar imaging (EPI) is standard for diffusion-weighted MRI due to motion insensitivity.
- However, EPI suffers from susceptibility artifacts and limited spatial resolution, especially at higher field strengths like 3 Tesla (T).
- Parallel imaging, such as GRAPPA, has limitations at higher field strengths.
Purpose of the Study:
- To develop and evaluate a novel MRI technique combining readout-segmented EPI and parallel imaging.
- To address susceptibility artifacts and improve spatial resolution in diffusion-weighted imaging at 1.5T and 3T.
- To achieve robust motion correction and clinically feasible scan times.
Main Methods:
- Utilized readout-segmented EPI combined with parallel imaging techniques.
- Incorporated a 2D navigator acquisition for nonlinear phase correction.
- Implemented real-time reacquisition of uncorrectable data.
- Performed measurements on healthy volunteers at 1.5T and 3T.
Main Results:
- Generated high-resolution, diffusion-weighted images.
- Achieved significant reduction in susceptibility artifacts compared to single-shot EPI.
- Demonstrated robust correction for motion-induced phase artifacts.
- Confirmed clinically suitable scan times.
Conclusions:
- The combination of readout-segmented EPI and parallel imaging offers improved diffusion-weighted imaging.
- This technique effectively reduces susceptibility artifacts and enhances image resolution at 1.5T and 3T.
- The method provides robust motion correction, making it suitable for routine clinical use.
