Figure 5.

Increment in longitudinal relaxation rate, R₁, at different Gd-DTPA/HA ratio (from 0 to 9) for: free Gd-DTPA in water (black squares); Gd-DTPA in 0.5% w/v HA solution (blue filled triangles); Gd-DTPA in 0.5% w/v HA crosslinked with DVS (blue empty triangles). The R₁ increment is calculated in percentage with respect to the corresponding R1 of Gd-DTPA in water. A fast increment in R₁ is observed until a 2.5 Gd-DTPA/HA ratio (Gd-DTPA concentration equal to 300 µM). For higher ratios (i.e. higher Gd-DTPA concentrations), the R₁ increment reaches a plateau.