Additively manufactured, solid object structures for adjustable image contrast in Magnetic Resonance Imaging.

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Materials Science

Background:

• Current Magnetic Resonance Imaging (MRI) phantoms are limited by material choices, primarily using water-filled or gel-based components.
• Additive manufacturing (AM) has enabled complex phantom geometries, but lacks controllable MRI contrast for mimicking biological tissues.
• There is a need for advanced MRI phantoms capable of simulating organ substructures and lesion heterogeneities.

Purpose of the Study:

• To introduce a novel AM design for MRI phantoms with adjustable contrast properties.
• To enable MRI contrast manipulation by controlling the partial volume of MRI-visible materials within voxels.
• To create realistic phantoms for simulating heterogeneous tumor tissues.

Main Methods:

• Designed and 3D printed two sets of 11 cubes and three spherical tumor models using AM.
• Utilized varying partial volume contributions of MRI-visible materials within the printed objects.
• Evaluated MRI contrast in standard MRI sequences based on spin density and partial volume signal variations.

Main Results:

• Most fabricated samples exhibited varied MRI contrast in standard MRI sequences.
• Contrast variations were primarily attributed to differences in spin density and partial volume effects.
• A smooth, continuous MRI contrast gradient was successfully generated within a single-compartment tumor model.

Conclusions:

• The novel AM approach allows for the creation of MRI phantoms with tunable contrast.
• This technique effectively mimics the appearance of heterogeneous biological tissues, particularly tumors.
• The developed concept facilitates the advancement of more sophisticated MRI phantoms for research and diagnostics.