This project will provide the first ground truth connection anisotropic diffusion phantom to reproduce human white matter using axon scale diffusion tubes and track 250 micron scale fascicle (bundles of axons) with a common path. The phantom will advance MR diffusion imaging, providing accurate calibration, quality assurance, and research advancement. It utilizes innovations in textile engineering, 3D printing, and computer controlled connection routing to reproduce human brain scale white matter tissue, allowing for the reproduction of actual connective networks using millions of filled 5-12 micron scale textile tubes. It will quantify the accuracy of connectome anatomical mapping, drive technical advancement of diffusion MRI acquisition and fiber tracking, and provide ground truth measurement for clinical and research MRI centers, as well as quality assurance for anatomical connectome based brain scientific and clinical imaging. We will quantify the accuracy of following a set of neural fasciculi within tracts and through crossings in complex brain mapping paths over long distance (relative) and across a series of test MRI reference object phantoms representative of human tissue to calibrate measurement. The Phase I effort will be a demonstration of feasibility of research and calibration utility, creating a series of novel anisotropic diffusion phantoms to quantify connection routing accuracy. We will use hollow textiles called Taxons (manufactured textile, axon-shaped, micron scale hollow tubes) reproducing biologically known routes of long distance axonal anatomy. This will provide the first quantitative reference standard for intra-axonal water. These phantoms will include water/D2O, Mn+ doped, or fluorescent dye filled Taxons providing 1,000 point-to-point manufactured fasciculi scale tracts of 64,000 filled Taxons. The phantoms will provide manufactured reproduction of connectivity geometry comparable to the mesoscale of the human visual system (eye to LGN, to V1, to V2, V4) with spatial topology matching animal scale tracer studies. This will quantify how well advanced diffusion imaging sequences can follow the connectivity patterns as a function of tract size, crossing, spread, number and diameter distribution of Taxons.
The Specific Aims are: 1) Develop a prototype multiscale manufactured standard reference taxon phantom for brain networks to demonstrate technical and economic feasibility to calibrate and advance MRI research; 2) Create a calibration brain tract/crossing MRI anisotropic phantom, and 3) Create a human scale connective phantom mapping the complexity in the visual system eye to layers of LGN. These will be tested with MRI (3T) and non-MRI methods (light and electron microscope, Micro CT, and textile industrial measurement). Testing will occur on 3T and 7T MRI (Siemens, GE, and Philips) magnets.
With no standard for accuracy, the field of MRI imaging has serious concerns about the accuracy of diffusion imaging precision to produce anatomically correct maps of known anatomy. This project will advance the quality and speed of MRI diffusion imaging to provide an anatomically accurate map of brain connectivity, providing quantitative calibration of MRI scans for white matter pathology impacting over 10 million US residents annually for disorders including brain trauma, tumors, developmental disorders, and neurodegenerative disorders at an economic cost of over $80 billion. It will also provide the first viable ground truth calibration of anisotropic diffusion to calibrate US connectome-based imaging with over $316 million dollars of research effort supported by current NIH and Department of Defense research programs.
