High-fidelity, accelerated whole-brain submillimeter in-vivo diffusion MRI using gSlider-Spherical Ridgelets (gSlider-SR)

TL;DR

This paper introduces gSlider-SR, a novel accelerated diffusion MRI technique that enables high-resolution, whole-brain in-vivo scans with significantly reduced acquisition time by exploiting data redundancy with spherical ridgelets.

Contribution

The paper presents gSlider-SR, a new method combining under-sampling and spherical ridgelets to accelerate high-resolution diffusion MRI without sacrificing data quality.

Findings

gSlider-SR accurately reconstructs high-quality diffusion data at various acceleration factors.

It achieves an eight-fold reduction in scan time for 860 μm resolution in vivo.

The method preserves signal and angular information comparable to conventional techniques.

Abstract

Purpose: To develop an accelerated, robust, and accurate diffusion MRI acquisition and reconstruction technique for submillimeter whole human brain in-vivo scan on a clinical scanner. Methods: We extend the ultra-high resolution diffusion MRI acquisition technique, gSlider, by allowing under-sampling in q-space and Radio-Frequency (RF)-encoded data, thereby accelerating the total acquisition time of conventional gSlider. The novel method, termed gSlider-SR, compensates for the lack of acquired information by exploiting redundancy in the dMRI data using a basis of Spherical Ridgelets (SR), while simultaneously enhancing the signal-to-noise ratio. Using Monte-Carlo simulation with realistic noise levels and several acquisitions of in-vivo human brain dMRI data (acquired on a Siemens Prisma 3T scanner), we demonstrate the efficacy of our method using several quantitative metrics. Results: For high-resolution dMRI data with realistic noise levels (synthetically added), we show that gSlider-SR can reconstruct high-quality dMRI data at different acceleration factors preserving both signal and angular information. With in-vivo data, we demonstrate that gSlider-SR can accurately reconstruct 860 ${\mu}m$ diffusion MRI data (64 diffusion directions at b = 2000 $s/ {mm}^2$), at comparable quality as that obtained with conventional gSlider with four averages, thereby providing an eight-fold reduction in scan time (from 1 h 20 min to 10 min). Conclusion: gSlider-SR enables whole-brain high angular resolution dMRI at a submillimeter spatial resolution with a dramatically reduced acquisition time, making it feasible to use the proposed scheme on existing clinical scanners.