Formula showing that the fiber orientation density function is proportional to the inverse Funk transform of the diffusion MRI signal.

Research Focus

The Jensen Lab develops novel MRI methods and applies them to the study of neuropathologies. In particular, diffusion MRI (dMRI) is used in a variety of ways to assess and quantify microstructural properties of brain. This enables microscale information for both white and gray matter to be obtained noninvasively and efficiently throughout the entire brain volume. The Jensen Lab closely collaborates with several other research groups in using dMRI to investigate a variety of neurological diseases such as Alzheimer’s disease, epilepsy, and stroke.

Alzheimer’s Disease

The Jensen Lab (in collaboration with Dr. Fatima Falangola) is investigating the ability of advanced dMRI methods to detect subtle changes in brain microstructure for 3xTg-AD mice, which develop both beta-amyloid plaques and neurofibrillary tangles, the two primary hallmarks of Alzheimer’s pathology. The mice are being scanned longitudinally from 2 months of age up until 18 months of age in order to follow the full course of disease progression. The overall goal of this project is to demonstrate the sensitivity of dMRI in detecting AD pathology at its earliest stages.

Fiber Ball Imaging

A single MRI voxel from white matter has as many as one million individual axons. Typically, these are arranged in complex geometrical patterns that can be quantified by the fiber orientation density function (fODF). Remarkably, using dMRI it is possible to measure the fODF in vivo. The fODF is used both for white matter fiber tractography and in formulating microstructural models that help with the interpretation of dMRI data. However, established methods for estimating the fODF are fairly crude. The Jensen Lab is developing a new approach called fiber ball imaging that takes advantage of theoretical insights and advances in MRI scanner technology with the goal of obtaining accurate high resolution fODF measurements. Such high fidelity fODFs may provide novel biomarkers of disease and aging.