Principal Investigators //
- David Bridwell, PhD >
- Vince Calhoun, PhD >
- Arvind Caprihan, PhD >
- Zikuan Chen, PhD
- Vince Clark, PhD >
- Eric D. Claus, PhD >
- Carla Harenski, PhD >
- Kent Hutchison, PhD >
- Kent A. Kiehl, PhD >
- Jeffrey D. Lewine, PhD >
- Jingyu Liu, PhD >
- Andrew R. Mayer, PhD >
- John Phillips, MD >
- Sergey Plis, PhD >
- Matthew Shane, PhD >
- Julia M. Stephen, PhD >
- Jing Sui, PhD >
- Jessica Turner, PhD >
- Qingbao Yu, PhD >
Zikuan Chen, PhD
Research Scientist
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.
Selected Publications //
- Task-evoked brain functional magnetic susceptibility mapping by independent component analysis (χICA >
- Nonlinear magnitude and linear phase behaviors of T2* imaging: theoretical approximation and Monte.. >
- Intrinsic functional brain mapping in reconstructed 4D magnetic susceptibility (χ) data space >
- Understanding the morphological mismatch between magnetic susceptibility source and t2* image. >
- Susceptibility-based functional brain mapping by 3D deconvolution of an MR-phase activation map. >
- Effect of object orientation angle on t2* image and reconstructed magnetic susceptibility…... >
- Blood oxygenation level-dependent functional MRI signal turbulence caused by ultrahigh spatial…... >
- Computed diffusion contribution in the complex blood oxygenation-level dependent fMRI signal >
- Volumetric BOLD fMRI simulation: from neurovascular coupling to multivoxel imaging. >
- Computed inverse MRI for magnetic susceptibility map reconstruction >
- A computational multiresolution BOLD fMRI model >
- Two pitfalls of BOLD fMRI magnitude-based neuroimage analysis: non-negativity and edge effect >
- Magnitude and phase behavior of multiresolution BOLD signal >
- Effect of surrounding vasculature on intravoxel BOLD signal >
- Compensating the intensity fall-off effect in cone-beam tomography by an empirical weight formula >
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.
