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3D printed models are poised to expand current investigations toward accurate functional CT and MR imaging that will likely open new horizons for diagnostic tool development that is not otherwise feasible due to patient considerations such as radiation burden, scan time, and monetary cost.
3D printing can produce hollow structures (e.g. vessels and airways) that, with appropriate selection of the printing technology (particularly with respect to the so-called "support" material) can replicate human physiology, including at the moment vascular compliance.
Vascular phantoms have been successfully created from rotational digital subtraction angiography, CR, and MRI data sets. Early attempts begun with negative molds, namely 3D printing of a solid lumen to be used as mold around which to cure a silicon "vessel" wall. At present, the “vessel” wall can be printed with high accuracy (<120 microns from the desired lumen geometry) directly, and can be either rigid or elastic.
A particularly important opportunity arises from the ability to perform precise in silico computational fluid dynamics (CFD) simulations on a given lumen geometry and concurrently perform identical in vitro flow experiments on 3D-printed phantoms of the same lumen geometry.
Arbitrary anatomies reflecting realistic pathophysiology that has been imaged can be compared in silico and in vitro, toward optimizing functional imaging techniques for in vivo applications, such as flow-encoded MRI or coronary Transluminal Attenuation Gradient (TAG) for the non-invasive detection of significant coronary artery disease.
The process for the latter application of in vitro CTA experiments to elucidate the intra-luminal kinetics of iodinated contrast agent that give rise to the TAG will be used as an example of the steps from in vivo image acquisition, to lumen segmentation and preparation for 3D printing, and in vitro experimentation.
Mitsouras, D,
Validation of Coronary Contrast Gradients Using 3D Coronary Phantoms. Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL.
http://archive.rsna.org/2014/14001895.html
