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 hete...
Source: NIH OTT Licensing Opportunities - Category: Research Authors: Source Type: research