MRI Research Group Members

The members of the group collaborate extensively with other researchers and clinicians, in the School of Medicine as well as River Campus and affiliated laboratories, to focus their multidisciplinary talents on problems to which imaging may contribute useful information. They also are engaged in fundamental studies designed to enhance the performance of MR imaging methods, and to better understand the nature of the information obtainable by different MRI techniques. Members of the Division undertake undergraduate, graduate and postdoctoral teaching and training at University of Rochester.

Jianhui Zhong, Professor of Radiology, BME, Physics & Astronomy
Tianliang (Tyler) Gu, Assistant Professor, Radiology and Rochester Center for Brain Imaging (RCBI)
Ling-chih Lin, Ph.D. student, Physics & Astronomy
Xiaoxu Liu, Ph.D. student, Electrical and Computer Engineering
Wei Tian, Post-Doctorial Fellow, Radiology
Madelina Trivarus, Post-Doctorial Fellow, Radiology and Rochester Center for Brain Imaging (RCBI)
Chung-ki Wong, Ph.D. student, Physics & Astronomy
Tong Zhu, Ph.D. student, Biomedical Engineer

Jianhui Zhong, Professor of Radiology, BME, Physics & Astronomy

BME link: http://www.bme.rochester.edu/bmeweb/faculty/zhong.html
P&A link: http://www.pas.rochester.edu/
Rad link: http://www.urmc.rochester.edu/radiology/findaphysician/profile.cfm?master_id=4255

 

Tianliang (Tyler) Gu, Assistant Professor, Radiology and Rochester Center for Brain Imaging

Research projects: iDQC (fMRI and Spectroscopy), MR angiography.

RCBI link:  http://www.rcbi.rochester.edu/people/tyler.html

 

Ling-chih Lin, Ph.D. student, Physics & Astronomy

Lisa, Ling-chih Lin received her B.S. (2002) and M.S. (2004) in physics from National Taiwan University and came to University of Rochester for her Ph. D. in 2005. Her area of interest is to construct the diffusion model and sequence in biological systems to investigate the anisotropy, fiber orientation/structure for the clinical Diffusion Tensor Imaging (DTI) diagnosis and to use quantitative approach to discriminate the axial/radial diffusivities/eigenvectors as parameters in imaging evolution.

Personal website:
http://web.pas.rochester.edu/~lingchih/

 

Xiaoxu Liu, Ph.D. student, Electrical and Computer Engineering

My research interests

My primary research interest is in distortion correction for EPI image, in particular, developing new and effective algorithm both in scanning and post processing to restore the distorted image, and using multiple reliable methods to evaluate the effectiveness of the correction algorithm.

Diffusion tensor imaging (DTI) has attracted great attention because of its potential use in studies of neurological disorders. Changes of fractional anisotropy (FA) and trace of tensor (Tr) have been used among other indices to indicate possible underlying pathological changes. For example, DTI parameters have been found to be important for early detection of Alzheimer's disease. DTI data are mostly collected with Echo Planar Imaging (EPI), which suffers great geometric distortion (stretch, compress, or shear) and dropout due to field inhomogeneity induced by the susceptibility difference of different tissues. These artifacts are more significant in phase encoding direction and they are worsened at higher magnetic fields. Although the geometric distortion and dropout is most severe at air-tissue interface such as temporal lobes and at surroundings of sinuses, small distortion and dropout in other areas such as surroundings of CSF can also cause misinterpreting and false value in DTI analysis. Distortion can also cause the inaccuracy of fiber tracking. Fiber tracking can even fail totally in areas with very severe distortions.

My current research project is using Genetic Algorithm (GA) to improve the accuracy of the phase reversal method for distortion correction.

I have a personal website:
http://liumichael.com

 

Wei Tian, Post-Doctorial Fellow, Radiology

 

My main research interest focuses on the clinical application of functional MR imaging techniques (such as DTI and MRS) in evaluating brain diseases (including multiple sclerosis).

Current project:

DTI study of multiple sclerosis--the longitudinal study of DTI as a marker of disease progression in multiple sclerosis

Madelina Trivarus, Post-Doctorial Fellow, Radiology and Rochester Center for Brain Imaging

Research interests

• Implementation and optimization of functional MRI for use in clinical setting as part of the standard assessment of the diseased brain.
• Functional MRI of language and other cognitive functions in neurologically normal individuals as well as in different patient populations.
• Magnetic Resonance Spectroscopy Imaging (MRSI) of the brain.

 

Madelina Trivarus, Post-Doctorial Fellow, Radiology and Rochester Center for Brain Imaging

Research Interests

• Implementation and optimization of functional MRI for use in clinical setting as part of the standard assessment of the diseased brain.
• Functional MRI of language and other cognitive functions in neurologically normal individuals as well as in different patient populations.
• Magnetic Resonance Spectroscopy Imaging (MRSI) of the brain.

Chung-ki Wong, Ph.D. student, Physics & Astronomy

My research focuses on the theoretical studies of the signal that is formed under the distant dipolar field (DDF).  In Magnetic Resonance Imaging (MRI), signal intensity, and hence image contrast, base on the variations of spin density and relaxation times of the sample.  Distant dipolar field is the spin-spin interactions among different molecules. The signal formed under the influence of DDF depends also on the local magnetic field variation.

It was found recently that when a linear magnetic gradient field is applied in a pulse sequence, the obtained DDF signal comes primarily from the neighboring spins located within a modulation period induced by the gradient field.  Since the achievable modulation period can be much smaller than the voxel size of an image, it has been suggested that by tuning the applied gradient field strength, the information of the subvoxel field distribution, and hence subvoxel structures, can be extracted from the image using DDF signal.

My current work is to understand how the DDF signal depends on the modulation length in the presence of simple subvoxel field distributions by using analytical method.

Related publications in journal and conference:

1. Theoretical studies of the effect of dipolar field in multiple spin-echo sequence with refocusing pulses of finite duration. J. Magn. Reson. In press, J. Mag. Reson (2007)
2. Effect of distant dipolar field and T2 on magnetization in CRAZED-multiecho pulse sequence, Proc. Intl. Soc. Mag. Reson. Med. 14, 2479 (2006).
3. Investigation of multiple-echo spin-echo signal acquisition under distant dipole-dipole interactions, Proc. Intl. Soc. Mag. Reson. Med. 13, 2288 (2005).
4. Enhanced contrast of signal from distant dipolar field on relaxation times on B0 in tissues, Proc. Intl. Soc. Mag. Reson. Med. 11, 183 (2004).

Tong Zhu, Ph.D. student, Biomedical Engineer

I am a fifth-year Ph.D. student in the Dept. Biomedical Engineering with interests in magnetic resonance imaging (MRI) and medical image processing. I’m pursuing Diffusion Tensor Imaging (DTI) research, a novel MRI technique for assessing brain white matter integrity in vivo, in Dr. Jianhui Zhong’s group.  My research involves in optimization of DTI technique and its applications in both healthy and diseased brain.

Current Research Activities:

1. Quantify measurement uncertainty of DTI parameters in human brain data using wild bootstrap analysis, a novel non-parametric statistical method;
2. Optimization of clinical DTI protocols with wild bootstrap analysis on human brain data;
3. Application of DT-tractography, e.g. tract-of-interest (TOI) method, to achieve better characterization of white matter integrity under pathological changes in diseased brain, such as mild Traumatic Brain Injury (mTBI) and Human Immunodeficiency Virus (HIV) associated dementia.

Hobbies

In my spare time, I devote myself to music (mostly classical, jazz and alternative rock), photograph, bicycling and go kayaking with my wife.

Contacts:
Tong Zhu
Department of Biomedical Engineering
Box 639, University of Rochester Medical Center
601 Elmwood Avenue, Rochester, NY 14642
Tel: (585)-275-5885 (O)
Email: tozhu@bme.rochester.edu

Personal webpage:
www.bme.rochester.edu/~tozhu