Research

Advanced arterial spin labeling (ASL) MRI Arterial spin labeling (ASL) is a non-invasive MRI technique for measuring cerebral perfusion by utilizing magnetically labeled arterial blood as an endogenous tracer. The most appealing feature of ASL compared to other imaging techniques is that it permits noninvasive and quantitative measurement of cerebral blood flow (CBF), which is an important physiological parameter. Our research interest in this direction is to develop advanced ASL MRI techniques except for working with conventional ASL. We have developed non-contrast enhanced time-resolved 4-dimensional MR angiography (4D MRA) technique based on arterial spin labeling (ASL) with high spatial and temporal resolution, which can be applied in clinical applications, such as cerebral malformations, to delineate the dynamic flow patterns. Dynamic ASL also provides in-vivo arterial blood flow and blood volume measurements. Except for conventional ASL perfusion imaging which labels all flowing spins in the tagging plane, we are also interested in vessel-selective ASL to specifically image the vascular territories from individual feeding arteries.

 

 

Fast dynamic imaging with non-Cartesian sampling Conventional Cartesian imaging especially 3D Cartesian requires a long acquisition time, which potentially hinders clinical utilities.  We are interested in developing fast non-Cartesian imaging techniques.  We have developed 4D MRA with stack-of-starts golden angle radial acquisition, which can provide flexible temporal resolution while preserving high-spatial resolution. In parallel, we are also interested in advanced image reconstruction algorithms, with which good image quality can be preserved at high undersampling rates. We have developed novel constrained reconstruction methods, such as magnitude-subtract compressed sensing and subspace low-rank reconstruction, for dynamic ASL imaging with radial acquisition.

 

 

Direct assessment of intracranial arterial stiffness/pulsatility Conventional Cartesian imaging especially 3D Cartesian requires a long acquisition time, which potentially hinders clinical utilities.  We are interested in developing fast non-Cartesian imaging techniques.  We have developed 4D MRA with stack-of-starts golden angle radial acquisition, which can provide flexible temporal resolution while preserving high-spatial resolution. In parallel, we are also interested in advanced image reconstruction algorithms, with which good image quality can be preserved at high undersampling rates. We have developed novel constrained reconstruction methods, such as magnitude-subtract compressed sensing and subspace low-rank reconstruction, for dynamic ASL imaging with radial acquisition.

 

 

Clinical translations in cerebrovascular disease and neurodegenerative diseases The ultimate goal of the NITT lab is to translate novel MRI techniques into a variety of clinical applications to improve the diagnosis and treatment of diseases. We have extensive experience in clinical translations of new MRI techniques. We are interested in applying cutting-edge non-invasive MR angiography and perfusion techniques to comprehensively characterize the hemodynamics and collateral circulation in patients with cerebrovascular disorders, such as stroke, intracranial atherosclerosis (ICAS), arteriovenous malformation, and moyamoya disease Another research interest in the clinical translation is to develop novel quantitative vascular imaging markers for aging, Alzheimer’s disease, and vascular dementia.