K-space and image-space combination for motion-induced phase-error correction in self-navigated multicoil multishot...

Area of Science:

• Magnetic Resonance Imaging
• Medical Physics
• Image Reconstruction

Background:

• Motion during diffusion encoding in multishot diffusion-weighted imaging (DWI) causes phase errors.
• These errors lead to signal cancellation, degrading image quality.
• Existing methods like direct phase subtraction (DPS) and conjugate gradient (CG) have limitations.

Purpose of the Study:

• Introduce a new, time-efficient algorithm for correcting rigid body motion-induced phase errors in multishot DWI.
• Address limitations of existing phase error correction methods.

Main Methods:

• Developed a novel k-space and image-space combination (KICT) algorithm.
• KICT estimates phase errors in image space using self-navigated variable density spiral trajectories.
• Correction is performed in k-space, preserving object and coil phases for parallel imaging.

Main Results:

• KICT effectively overcomes aliased phase errors.
• Demonstrated improved signal-to-noise ratio (SNR) in diffusion-weighted images and better resolved fiber tracts in fractional anisotropy (FA) maps compared to DPS.
• KICT performance is comparable to CG in peripheral-gated acquisitions.

Conclusions:

• KICT offers an efficient and flexible solution for motion-induced phase error correction in multishot DWI.
• The algorithm enhances image quality and is compatible with various parallel imaging reconstruction methods.
• KICT represents a significant advancement for motion-corrupted diffusion MRI.