Accelerated High-Resolution T₁-Weighted MRI Using Magnetization-Prepared Echo-Planar Imaging With Steady-State Echo...

The goal is to redesign the three-dimensional (3D) Magnetization-Prepared Rapid Acquisition Gradient Echo (MP-RAGE) sequence by integrating multi-shot echo-planar imaging (EPI) acceleration with steady-state echo pathway enhancement, enabling simultaneous scan time reduction and contrast enhancement. The new approach improves clinical workflow, lowers scan cost, and reduces potential movement artifacts.

A magnetization-prepared multi-shot EPI readout with a short echo train length is used to replace the conventional gradient-echo readout in 3D MP-RAGE. Unlike standard MP-RAGE, which suppresses residual transverse magnetization via RF spoiling, the proposed sequence partially retains steady-state echo pathway signals to boost tissue contrast. Multi-shot EPI readouts provide intrinsic acceleration while maintaining controlled echo train length to minimize geometric distortion and retain spatial resolvability. Experiments were performed at 1 × 1 × 1 mm³ isotropic resolution (FOV = 256 × 240 × 208 mm³, TR = 2.3 s, TI = 900 ms, partial Fourier = 7/8) with a parallel imaging factor of 2. Conventional 3D MP-RAGE served as a reference.

An EPI echo train length of 4 with steady-state signal enhancement provided superior performance, enhancing gray-white matter contrast while minimizing distortion, as compared with MP-RAGE. Specifically, the proposed method achieved a > 50% increase in contrast-to-noise ratio (CNR) together with a > 3.5-fold reduction in acquisition time (from 4 min 42 s to 1 min 15 s). The observed contrast enhancement arises from steady-state echo pathway contributions that are normally suppressed in standard implementations.

The method enables rapid, high-resolution T1-weighted imaging with improved CNR and substantial time savings, offering a practical pathway toward next-generation structural MRI.