Patent application number | Description | Published |
20090010517 | NON-INVASIVE IN VIVO MRI AXON DIAMETER MEASUREMENT METHODS - Magnetic resonance methods include modeling magnetic resonance signals obtained from specimens at low and high q-values to obtain parameters and distributions of parameters associated with specimen structure and orientation. In evaluation of brain white matter specimens, diffusion within axons can be modeled based on hindered diffusion parallel to an axis of the axon and restricted diffusion perpendicular to the axis. Diffusion exterior to axons can be modeled as hindered diffusion with differing diffusivities parallel to and perpendicular to the axis. Based on extracted parameters and associated model functions, distributions of specimen properties such as intra and extra-axonal principal diffusivities and the corresponding principal directions can be estimated. Features of the axon diameter distribution can also be estimated using this approach. | 01-08-2009 |
20100033182 | MAGNETIC RESONANCE SPECIMEN EVALUATION USING MULTIPLE PULSED FIELD GRADIENT SEQUENCES - Using pulsed-field-gradient (PFG) sequences, the sizes of the pores in ordered porous media can be estimated from the “diffraction” pattern that the signal attenuation curves exhibit. A different diffraction pattern is observed when the experiment is extended to a larger number (N) of diffusion gradient pulse pairs. Differences in the characteristics of attenuation curves also permit distinguishing different pore shapes and distributions using the N-PFG technique. Using an even number of PFG pairs, an approximation to the average pore size can be obtained even when the sample contains pores with a broad distribution of sizes. Multi-PFG sequences can also be used to differentiate free and multi-compartment diffusion, and to estimate compartment sizes and orientations, and to distinguish microscopic and ensemble anisotropy. | 02-11-2010 |
20120068699 | PHANTOM FOR DIFFUSION MRI IMAGING - A phantom calibration body ( | 03-22-2012 |
20140357979 | MRI TRACTOGRAPHY BASED TRANSIT TIME DETERMINATION FOR NERVE OR MUSCLE FIBERS - Magnetic resonance methods comprise tractographically establishing a path along a structure in a specimen and finding a distribution of structure radii or cross-sectional areas along the path. Based on the distribution and the path, end-to-end functional characteristics of the structure are estimated. For example, nerve transit times or distributions of transit times can be estimated for a plurality of nervous system locations such as Brodmann areas. Comparison of estimated transit times or distributions thereof between reference values or other values from the same structure can be used to assess specimen health. | 12-04-2014 |