CT phantom with 3D anthropomorphic, contrast-enhanced texture
Physical phantoms with realistic anatomical texture and composition (including contrast media) are of high value and relevance in evaluating the performance of clinical computed tomography (CT) imaging systems. They can offer assessments of image quality in a manner that is more relevant than existing phantoms. The goal of this project was to fabricate anatomically structured 3-D liver texture with added contrast-enhancement. The study used an inkjet printer and customized ink. Patient-informed liver texture with contrast details was first defined computationally and the needed material for each tissue type was estimated for each voxel to produce attenuations from -200 to +300 HU, with subtle 5-20 HU lesions. Volumetric data were printed, one sheet of paper at a time, using “soft tissue” ink based on 200mg/cc sodium bromide (NaBr), and “enhanced tissue” ink based on Isovue-300. The phantom was scanned on a commercial CT system (Siemens SOMATOM Definition Flash) using a clinical protocol. The results show targeted heterogeneity and enhancement as designed with subtle artifacts associated with uneven air contamination. In ongoing work, we plan to use this method to create anatomically and morphologically accurate liver and lung lesions with texture for use in dual energy CT.