Research

1. Neurofluid dynamics (MRI, Near Infrared Spectroscopy)

Proper brain health is essential for humans to live a satisfactory life. The health of the brain is determined by the delivery of nutrients and the removal of waste products, which is an established function of the blood. However, recent discoveries have led scientists to believe that cerebrospinal fluid (CSF) is also involved in the disposal of waste products. CSF is the clear fluid in which the brain is suspended, and it protects the brain from mechanical damage. Research has shown that the CSF also functions as a garbage disposal system within the brain. But unlike blood, which has the heart to pump it throughout the body, the CSF does not have its own pump to help it flow through the brain. Due to the lack of a direct pump to disperse CSF throughout the brain, there is a major new field of research dedicated to understanding the mechanisms behind the flow of CSF throughout the brain. To increase knowledge of CSF flow, my research focuses on understanding the mechanisms that propel CSF through the brain in humans. Specifically, this project focuses on using multiple MRI techniques to assess how changes in cerebral blood changes are coupled to CSF motion.

2. Sleeping study (MRI, Near Infrared Spectroscopy, EEG and RespiRact)

One enduring mystery across various life forms, including humans, is the essential need for sleep, a phenomenon for which a conclusive explanation has yet to be found. A recent theory posits that sleep is critical for removing toxic chemical byproducts of brain activity. Failure to adequately eliminate these substances can have immediate negative effects and may also increase the risk of neurodegenerative (e.g., Alzheimer's Disease) and neurodevelopmental disorders over time. Our research utilizes a comprehensive suite of imaging techniques (MRI, EEG, NIRS, etc.) to examine the dynamics of cerebrospinal fluid and cerebral blood flow and their interaction, which are believed to play a crucial role in the elimination of brain waste. The objective is to identify imaging biomarkers that can quantify the effects of sleep and to develop interventions that optimize this essential biological function. This study is conducted in collaboration with Prof. A.J. Schwichtenberg at Department of Human Development and Family Science, Purdue University.

3. Cerebral vascular diseases (fMRI, DTI, NIRS)

3.1 Neurodegenerative

The main aim of this work is to utilize a conventional resting-state functional MRI (rs-fMRI) scan to assess arterial stiffness and microvascular health through the development and implementation of specialized image processing techniques. The short-term goal of this work is to evaluate how these vascular health metric change with typical aging (30 to 100 years old). The long-goal of this work is to translate these techniques in an Alzheimer’s disease cohort to evaluate the interaction between vascular health and cognitive function.

3.2 Sickle cell disease

Sickle cell disease (SCD) is a genetic blood disorder characterized by the production of abnormal hemoglobin known as hemoglobin S, which leads to reduced oxygen-carrying capacity of the blood. This reduced blood oxygenation can trigger cerebrovascular remodeling, leading to a higher risk of cerebrovascular disease and cognitive impairment. We are investigating the hemodynamic mechanisms of SCD through functional magnetic resonance imaging (fMRI) and their relationship with hematological parameters. We utilize the patterns of systemic low-frequency oscillations within the blood oxygen level-dependent (BOLD) fMRI signal to discern oxygen levels in the brain and characterize distinct blood flow patterns in patients with SCD.

3.3 Traumatic brain injury and spinal cord injury

This project aims to examine hemodynamic correlations between the brain and spinal cord to draw baselines for future injury studies.

4. fMRI and DTI data interpretation (fMRI, DTI, NIRS, Transcranial ultrasound)

4.1 Understand different contrasts in fMRI and DTI data

The assessment of cerebral vascular health with common MRI techniques:

Understanding Relationship in Cerebral Blood Velocity and Flow:

This project aims to understand the relationship between cerebral blood velocity and cerebral blood flow. Cerebral blood velocity is measured with transcranial Doppler ultrasound and cerebral blood flow is measured with NIRS. It also seeks to understand how blood pressure and respiration impact this relationship. 

Understand cerebral blood volume and cerebrospinal fluid dynamics in neurodegenerative diseases:

Neurodegenerative diseases like Alzheimer’s disease (AD) accelerate brain atrophy. This project aims to use conventional resting-state fMRI (rs-fMRI) to investigate how a reduction in brain volume may alter the coupling between cerebral blood volume and cerebrospinal fluid.

4.2 Robust data-driven cerebral vessel segmentation using fMRI

With the growing interest in neurofluid dynamics, researchers are increasingly studying large cerebral arteries to better comprehend hemodynamics and their link to cerebrospinal fluid dynamics. Currently, time-of-flight (TOF) imaging is the gold standard for cerebral artery segmentation but is unavailable in most existing magnetic resonance imaging (MRI) databases. In this project, our objectives are twofold: (1) to create a dependable and resilient data-driven method for segmenting cerebral arteries through fMRI, and (2) to enhance the pipeline, extending its applicability to superior sagittal sinus segmentation.

5. Human-pet study (NIRS)

Dogs are an important part of many people's lives and interactions with them are known to increase endorphin and dopamine release. In this study, we examine the impact of the human-dog interaction in reducing stress in both humans and animals through non-invasive near-infrared spectroscopy. This study is conducted in collaboration with Prof. Niwako Ogata at Department of Veterinary Clinical Sciences, Purdue University.