Time Efficient Multi-Pulsed Field Gradient (mPFG) MRI Without Concomitant Gradient Field Artifacts

Measuring and mapping nervous tissue microstructure noninvasively is a long sought-after goal in neuroscience. Clinically, several neuropathologies such as cancer and stroke, are associated with changes in tissue microstructure. Diffusion tensor imaging (DTI), which models diffusion anisotropy, is an ideal imaging modality to elucidate these changes. However, DTI provides a mean diffusion tensor averaged over the entire MRI voxel. This has limitations when applied to heterogeneous neural tissue. Although some of these could be overcome by increased spatial resolution, this comes at the cost of reduced signal-to-noise ratio (SNR) and increased scan time. The SNR limitation makes it impractical to resolve individual neuronal soma and axons whose size range between 0.1-60 µm. Multiple pulsed field gradient (mPFG) methods can resolve microscopic features several orders of magnitude smaller than the typical MRI voxel size – for example, plant cell size and pore diameters in phantoms – using lower gradient strengths compared to single PFG methods.

This technology describes methods and apparatus to measure and map the diffusion tensor distribution (DTD) in neural tissue or other specimens. Efficient and translatable methods of performing mPFG MRI experiments in a single spin echo sequence to generate b-matrices of ranks one, two, or three, without concomitant gradient field artifacts are disclosed. The disclosed approaches and signal inversion framework captures features of heterogeneity and anisotropy in the spinal cord or other specimens. The disclosed stains may have utility in assessing disease (e.g., cancer), normal and abnormal developmental processes, degeneration and trauma in the brain and other soft tissues, and other applications.

The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) seeks research co-development partners and/or licensees for the development of diffusion tensor distribution MR imaging (DTD-MRI) in assessing disease (e.g., cancer), normal and abnormal developmental processes, degeneration and trauma in the brain and other soft tissues, or in other applications.

Competitive Advantages:

Superior non-invasive measurement and mapping of nervous tissue microstructure
Better time efficiency relative to other multiple pulsed field gradient (mPFG) techniques
Well-defined diffusion timing parameters for q-space MRI analysis
Reduction of concomitant gradient field artifacts

Commercial Applications:

Neuro or whole-body MRI suites for disease assessment in neural or other tissues.

Detection of microscopic anisotropy and heterogeneity within neural tissue (including the spinal cord)

Assessing disease (e.g., cancer), normal and abnormal developmental processes, degeneration and trauma in the brain and other soft tissues, and other applications