DTI PhantomMaker: A 3D-Printed DTI Calibration Phantom for Water Diffusion Direction and Anisotropy in the Brain

Abstract

As diagnostic tools, MRI scanners performing Diffusion Tensor Imaging (DTI) require calibration to ensure standardization. This thesis presents a custom-designed 3D printer used to manufacture a novel type of DTI phantom, which can then provide a standard reference to which machines performing DTI can be tuned. The phantom is comprised of an array of 3D-printed 1 cm3 blocks, each of which corresponds to a known value of diffusion anisotropy and direction. In the calibration process, measurements of these cubes from an uncalibrated scanner can then be compared to the blocks’ known properties. To achieve blocks of differing anisotropy, the 3D printer mixes fibrous (anisotropic) and non-fibrous (isotropic) polymer filaments in different ratios during printing. To achieve blocks of differing diffusion direction, the block is printed at various oblique orientations in space. Results from DTI scans of the phantom demonstrate the 3D printer’s ability to consistently print blocks of defined diffusion anisotropy and direction, suggesting (1) the viability of this type of 3D-printed phantom in serving as a calibration tool, and (2) the printer’s ability to effectively fabricate such phantoms.