Shuffled magnetization-prepared multicontrast rapid gradient-echo imaging.

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Imaging Technology
• Image Reconstruction Algorithms

Background:

• Magnetization-prepared imaging enables diverse contrast generation in MRI.
• Acquisition and reconstruction methods are crucial for efficient 3D multicontrast imaging.
• Accelerated imaging techniques are needed to reduce scan times without compromising image quality.

Purpose of the Study:

• To develop a novel acquisition and reconstruction method for 3D multicontrast rapid gradient-echo imaging.
• To utilize Hankel matrix completion combined with compressed sensing and parallel imaging.
• To enhance efficiency in magnetization-prepared MRI sequences.

Main Methods:

• Implemented a random k-space shuffling strategy at 7T for 3D inversion recovery, T2/diffusion, and magnetization transfer imaging.
• Combined compressed sensing (total variation, spatial-temporal low-rank) with parallel imaging and pixel-wise Hankel matrix completion.
• Enabled reconstruction of tens of multicontrast 3D images from 3- or 6-minute scans.

Main Results:

• Simulations demonstrated robust reconstruction of signal-recovery curves with 16x acceleration.
• In vivo studies achieved 4x to 24x accelerations across various preparation methods.
• Improved contrast was achieved by resolving pixel-wise signal-recovery curves post-magnetization preparation.

Conclusions:

• The novel method significantly improves acquisition efficiencies for magnetization-prepared MRI.
• Tens of multicontrast 3D images can be recovered from a single scan.
• The method is robust against noise, applicable to multi-exponential signals, and requires no prior model parameters.