Design, construction and validation of a magnetic particle imaging (MPI) system for human brain imaging.

Magnetic particle imaging (MPI) was introduced in 2005 as a promising, tracer-based medical imaging modality with the potential for high sensitivity and spatial resolution. Since then, numerous preclinical devices have been built but only a few human-scale devices, none of which targeted functional neuroimaging. In this work, we probe the challenges of scaling the technology to meet the needs of human functional neuroimaging with sufficient sensitivity for detecting the hemodynamic changes following brain activation with a spatio-temporal resolution comparable to current functional magnetic resonance imaging approaches.

Romer-EPTI: Rotating-view motion-robust super-resolution EPTI for SNR-efficient distortion-free in-vivo mesoscale diffusion MRI and microstructure imaging.

Purpose: To overcome the major challenges in diffusion MRI (dMRI) acquisition, including limited SNR, distortion/blurring, and susceptibility to motion artifacts.

Theory And Methods: A novel Romer-EPTI technique is developed to achieve SNR-efficient acquisition while providing distortion-free imaging, minimal spatial blurring, high motion robustness, and simultaneous multi-TE imaging. It introduces a ROtating-view Motion-robust supEr-Resolution technique (Romer) combined with a distortion/blurring-free Echo Planar Time-resolved Imaging (EPTI) readout.

Single-shot echo planar time-resolved imaging for multi-echo functional MRI and distortion-free diffusion imaging.

Purpose: To develop a single-shot SNR-efficient distortion-free multi-echo imaging technique for dynamic imaging applications.

Methods: Echo planar time-resolved imaging (EPTI) was first introduced as a multi-shot technique for distortion-free multi-echo imaging. This work aims to develop single-shot EPTI (ss-EPTI) to achieve improved robustness to motion/physiological noise, increased temporal resolution, and higher SNR efficiency.

Reduced physiology-induced temporal instability achieved with variable-flip-angle fast low-angle excitation echo-planar technique with multishot echo planar time-resolved imaging.

Purpose: Echo planar time-resolved imaging (EPTI) is a new imaging approach that addresses the limitations of EPI by providing high-resolution, distortion- and T/  blurring-free imaging for functional MRI (fMRI). However, as in all multishot sequences, intershot phase variations induced by physiological processes can introduce temporal instabilities to the reconstructed time-series data. This study aims to reduce these instabilities in multishot EPTI.