Three-dimensional diffusion imaging with spiral encoded navigators from stimulated echoes (3D-DISPENSE)

Area of Science:

• Magnetic Resonance Imaging
• Medical Physics
• Neuroimaging

Background:

• Motion artifacts are a significant challenge in 3D multishot diffusion imaging.
• These artifacts, particularly phase incoherence, degrade image quality and diagnostic accuracy.
• Existing methods often compromise image signal-to-noise ratio (SNR) or fail to fully correct motion effects.

Purpose of the Study:

• To introduce and evaluate a novel motion-insensitive technique for 3D multishot diffusion imaging.
• The method, termed 3D-DISPENSE (3D spiral-encoded navigators from stimulated echoes), aims to correct motion-induced phase incoherence.
• To achieve high-quality diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) with improved resolution and coverage.

Main Methods:

• The 3D-DISPENSE sequence utilizes a 3D stack-of-spiral navigator acquired between diffusion preparation and turbo spin-echo imaging.
• Navigators are generated from the twin pathway of a stimulated echo, separating acquisition from readout without SNR compromise.
• An iterative image reconstruction algorithm incorporates navigator phase information to correct intershot phase incoherence caused by motion.

Main Results:

• Phantom experiments demonstrated accurate estimation of introduced phase errors and significant mitigation of motion artifacts in DWI.
• The apparent diffusion coefficient (ADC) values remained identical to the reference after 3D-DISPENSE correction.
• In vivo brain DTI experiments showed near-perfect removal of phase-incoherence artifacts from various motion sources, yielding distortion-free DWI and fractional anisotropy maps at 1.5-mm isotropic resolution.

Conclusions:

• Three-dimensional DISPENSE effectively corrects motion-induced phase-incoherence artifacts in 3D multishot diffusion imaging.
• The method enables the production of high-quality 3D DWI and DTI.
• 3D-DISPENSE offers a robust solution for motion-insensitive diffusion imaging, improving diagnostic utility.