Changho Choi, Ph.D.
Changho Choi, Ph.D., is developing new magnetic resonance spectroscopic (MRS) techniques to enable researchers and clinicians to see concentrations of key chemicals in the brain. His techniques can produce measures of these chemicals at localized areas in the brain, or MRS images that reveal concentrations of the chemicals throughout the brain. Researchers have discovered altered levels of these chemicals—such as GABA, glutamate, glutamine, glycine, glutathione, serine, and lactate—in diseases including brain tumors, Alzheimer's disease, schizophrenia, and depression.
Thus, the ability to easily and noninvasively measure concentrations of these chemicals in the brain could enable oncologists diagnose brain tumors, to predict their aggressiveness, and to follow the progress of treatment. Measuring these chemicals could also enable researchers to better understand the pathologies underlying schizophrenia, depression, and Alzheimer's disease, and to explore new treatments.
The current technique for diagnosing brain tumors is positron emission tomography (PET), which involves injecting a radioactive tracer into the body and imaging its preferential uptake by tumors. However, PET gives only a general view of a tumor and does not reveal specific information about its molecular machinery. Also, unlike MRS, PET requires the use of radioactive isotopes.
In his research, Dr. Choi is developing MRS strategies of applying specially tailored sequences of RF pulses to optimize magnetic resonance signals from brain chemicals, and spectral editing techniques to tease apart the sometime overlapping signals in a spectrum, to reveal concentrations of individual molecules.
He is proceeding to clinical studies to explore applications of these techniques. For example, he is performing comparative MRS analysis of the brains of schizophrenic and normal subjects to measure levels of GABA, glutamate, and glutamine. Some studies have indicated that schizophrenics have altered brain glutamate levels. He will also test whether such levels are correlated with the disease symptoms, or with cognitive or electrophysiological measurements of the brain. Such correlations could mean that MRS analysis will offer useful insight into the disease and possible treatments.
Dr. Choi is also developing the first techniques to measure brain chemicals that are signatures of specific cancers. For example, he is measuring levels of the chemical 2-hydroxyglutarate (2HG), which accumulates only in gliomas that have specific gene mutations. He is also measuring alterations in glycine and glutamine levels in gliomas. Such gliomas are more successfully treated than others, indicating that measurement of such oncometabolites could enable researchers to predict treatment outcomes.
For publication information please view Dr. Choi's faculty profile.