Diffusion-weighted interleaved echo-planar imaging with a pair of orthogonal navigator echoes

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Imaging Technology
• Neuroimaging

Background:

• Conventional diffusion-weighted imaging (DWI) methods can be sensitive to patient motion and image distortions.
• Single-shot imaging techniques, while fast, often suffer from artifacts that compromise image quality.
• There is a need for efficient and robust DWI methods that can accurately capture anatomical and pathological information.

Purpose of the Study:

• To present and evaluate a novel diffusion-weighted interleaved echo-planar imaging (DW IEPI) method.
• To demonstrate the efficacy of cardiac gating and navigator-based motion correction in improving DWI quality.
• To assess the performance of DW IEPI in phantom and clinical settings, including patients with neurological conditions.

Main Methods:

• Development of a diffusion-weighted interleaved echo-planar imaging (DW IEPI) sequence suitable for various MRI hardware.
• Implementation of a motion correction strategy using orthogonal navigator echoes to correct for phase inconsistencies.
• Integration of cardiac gating for improved temporal resolution and artifact reduction.
• Validation using a rotating phantom to assess motion correction capabilities and clinical application in a volunteer and a patient with ischemia.

Main Results:

• The DW IEPI method, combined with cardiac gating and motion correction, proved to be time-efficient.
• The motion correction scheme effectively reduced ghost artifacts caused by patient movement in both readout and phase-encoding directions.
• The technique demonstrated robustness in phantom studies and provided diagnostically relevant images in a clinical case of cerebral ischemia.

Conclusions:

• The presented DW IEPI method offers a robust and time-efficient approach for diffusion-weighted MRI.
• Navigator-based motion correction significantly enhances image quality by mitigating motion-induced artifacts.
• This technique holds promise for improved diagnostic imaging in various neurological applications, particularly in the presence of patient motion.