Principal Investigators //

Zikuan Chen, PhD

Research Scientist

Zikuan Chen

Magnetic resonance imaging (MRI) is a noninvasive imaging modality that produces complex-valued images. Currently, only MR magnitude images are used for brain mapping and neuroimaging.  Dr. Chen’s research has indicated that a MR magnitude image is not a replica of the underlying magnetic susceptibility source, and that the magnetic susceptibility source can be reconstructed by computed inverse MRI (CIMRI).  Dr. Chen’s current research includes 3D and 4D magnetic susceptibility tomography by CIMRI, computational BOLD fMRI, brain susceptibility imaging, neurovascular coupling and neuroimaging.

Email Dr. Chen

BOLD fMRI Simulation

This project aims to look inside the BOLD fMRI mechanism (from the neurovascular coupling to multivoxel T2* imaging) by numerical simulations and numerical characterization.  Typical topics include: 1) MR magnitude and phase behaviors with respect to image resolution, echo time, vasculature, field strength, diffusion effect, etc; 2) Morphological mismatch between the magnetic susceptibility source and MR image; 3) Nonlinearity of T2*MRI; 4) Isotropic diffusion in gray matter and anisotropic diffusion in white matter; 5) Computed inverse MRI (CIMRI); and 6) 3D and 4D magnetic susceptibility tomography.

4D Magnetic Susceptibility Tomography

Our recent research shows that the MR magnitude image is not a replica of inter magnetic susceptibility distribution (the underlying vascular source of T2*MRI) and the magnetic susceptibility source can be reconstructed by a computed inverse MRI (CIMRI) technique.  This project aims to reconstruct a 3D internal magnetic susceptibility source distribution (3D magnetic susceptibility tomography) from a T2*MRI phase image and to reconstruct a 4D magnetic susceptibility dataset (4D magnetic susceptibility tomography) from a BOLD fMRI dataset and advocate to upgrade the biomedical tissue imaging and neuroimaging based on the reconstructed magnetic susceptibility database.

Exploration and Exploitation of MRI Phase Data

The output of T2*MRI is a complex-valued MR image.  Conventionally, the MR magnitude images are adopted for brain imaging (structural and functional) and the MR phase images remain unused. This project aims to understand the imaging mechanism of T2*MRI and to explore ways making use of the MRI phase data for brain imaging.