Figure 6.

CT images of treated and untreated 3D printed scaffolds, with grayscale values corresponding to their radiopacity in Hounsfield units (HU). (A) Three-dimensional volume rendered CT image showing increased surface radiopacity following treatment with TiO₂, titanium(IV) butoxide, and TEOS–titanium(IV) butoxide coatings. TEOS and APTES-treated scaffolds show a radiopacity similar to that of the untreated material. (B) CT cross sections show that the chemical treatments are limited to the surface in the cases of TiO₂, titanium(IV) butoxide, and TEOS–titanium(IV) butoxide, whereas TEOS and APTES are not detectable because of their radiopacity comparable to that of the untreated scaffolds. (C) CT signal intensity (HU) along a line horizontally bisecting the corresponding scaffolds shown above in (A,B).