Distortion-free 3D diffusion imaging of the prostate using a multishot diffusion-prepared phase-cycled acquisition...

Area of Science:

• Magnetic Resonance Imaging
• Medical Physics
• Radiology

Background:

• Prostate imaging requires accurate apparent diffusion coefficient (ADC) maps.
• Geometric distortion in diffusion-weighted imaging (DWI) can affect diagnostic accuracy.
• Existing methods may be limited by distortion and acquisition time.

Purpose of the Study:

• To develop and validate a novel technique for generating 3D distortion-free ADC maps of the prostate.
• To utilize a multishot diffusion prepared-gradient echo (msDP-GRE) sequence combined with ADC dictionary matching.
• To overcome limitations of current prostate diffusion imaging.

Main Methods:

• Implemented a 3D Cartesian, centric k-space trajectory with center oversampling in the msDP-GRE sequence.
• Employed k-space center averaging and phase cycling to mitigate motion and eddy current artifacts.
• Used Extended-Phase-Graph (EPG) simulations and ADC dictionary matching for T1 effect compensation and undersampled reconstruction.
• Validated the approach in a kiwifruit phantom and tested in vivo feasibility in healthy subjects.

Main Results:

• The msDP-GRE sequence with dictionary matching successfully recovered signal magnitude and produced distortion-free prostate ADC maps.
• No significant difference was found between ADC values from msDP-GRE and clinical standard single-shot echo-planar imaging (ssDW-EPI).
• In vivo scans showed no geometric distortion, and prostate ADC values aligned with published literature.

Conclusions:

• Achieved non-distorted 3D apparent diffusion coefficient (ADC) maps of the prostate.
• The multishot diffusion prepared (msDP) sequence with dictionary matching is effective for prostate imaging.
• This technique offers a promising alternative for accurate prostate diffusion MRI.