BrainMap: Jie Luo, PhD

Wednesday, April 6, 2016 - 12:00 to 13:00
149 13th Street (Building 149), main second floor seminar room (2204)

On the Nature of Brain MR Signal Phase

and Its Potential Applications in Monitoring Multiple Sclerosis and Assessment of Placental Health

The fundamental relationship between MRI signal phase and tissue properties has been a hot topic under debate, along with the development and increased popularity of the novel MR technique Quantitative Susceptibility Mapping (QSM). The objective of this talk is to give an overview of the contributing factors of MR signal phase in the brain tissue such as protein, lipids, iron and deoxyghemoglobin, as well as their contributing mechanism: magnetic susceptibility effect and chemical exchange effect. I will further discuss potential applications of phase contrast in

1) monitoring white matter tissue damage of Multiple Sclerosis lesions: Contrary to an expectation that the phase contrast change in multiple sclerosis lesions should be monotonic with loss of tissue content (which happens for MR magnitude-based contrast mechanisms), we show that phase contrast can actually disappear with extreme tissue destruction;

2) monitoring placental function: placental transport is vital for fetal wellbeing especially in late gestation, yet non-invasive measurement of placental transport is not available. Our pilot study with maternal hyperoxygenation has demonstrated that oxygen delivery timing is associated with fetal growth. Oxygenation quantification in utero is proposed to have great impact on assessment of placental transport.