MRI Physics and fMRI appications

My research focuses on two fundamental problems that become increasingly important in high field MRI. The problems include magnetic susceptibility effects on the static magnetic and the dielectric effects on the radio-frequency (RF) field. The current is focused on three areas. These three areas of research are closely related to one another and all relate to high field MRI technology.

1. T2* contrast imaging and its applications.
T2* contrast techniques have become increasingly useful for their unique tissue contrast. T2* image contrast is sensitive to variation in tissue bulk magnetic susceptibility. The T2* contrast provide a useful tool for brain research. One important application is the assessment of relative brain iron concentration. Brain iron dysregulation and resultant deposition have been implicated in many common degenerative diseases such as Alzheimer?s disease (AD), Parkinson?s disease (PD) and multiple sclerosis (MS). Unfortunately, T2* contrast for research and clinical investigations is limited by two major problems in existing techniques:
i. Severe artifact and loss of signal due to magnetic field inhomogeneity,
ii. Low contrast to noise ratio (CNR).
The research objective is to exploit the full potential of T2* contrast by developing reliable T2* contrast-enhanced imaging methods for brain research and clinical examinations.

2. Olfactory deficit in AD and olfactory functional MRI
The behavioral and neuropathological findings of preferential involvement of the central olfactory pathways in the early stages of AD makes olfaction an important system for investigation of AD with fMRI. The purpose of this project is to develop a reliable olfactory fMRI technique for clinical research on olfactory deficits occurring in early AD patients. This study can be correlated with the iron deposition using T2* contrast as mentioned above. This project involves rapid MRI methodology development as well as medical application of fMRI.

3. Radio frequency field and dielectric materials in high field MRI
It is desirable to increase the static magnetic field strength because MR image quality and sensitivity are expected to improve at higher field strength. The RF field becomes significantly inhomogeneous at high fields due to the strong wave behavior of the RF field. The understanding and eventual utilization of the wave behavior are fundamentally important for the development of high field NMR. Computer modeling is used to study the interaction between RF field and dielectric materials including tissues. Dielectric materials can be used in various ways to manipulate the RF field and their potential applications are enormous.