Table 3.

Average relaxivity (R1 and R2) values. N is the number of imaging sessions. The hydrogels and MR instrumentation showed stability over time as indicated by the small standard deviation obtained from measurements performed repeatedly over several months. R2 values for HA (p=0.007) and TS-HA (p=0.012) were significantly different than for TB-HA (cross-linked). R2 values for CO (p=0.020) and TS-CO (p=0.019) were significantly different than for TB-CO (cross-linked). HA hyaluronan; GE gelatin; CO composite, 1:1 HA:GE; TS-HA tyramine-substituted HA; TS-GE tyramine-substituted GE); TS-CO (tyramine-substituted CO); TB-HA (tyramine-based HA - cross-linked); TB-GE tyramine-based GE - cross-linked; TB-CO tyramine-based CO -cross-linked; Agar; Gd Magnevist, Gd-DTPA⁻²

Sample	R1 (l g−1 s−1)	R2 (l g−1 s−1)	N
HA	0.0027±0.0003	0.025±0.003	5
TS-HA	0.0030±0.0004	0.027±0.003	4
TB-HA	0.0033±0.0003	0.036±0.006	4
GE	0.0032±0.0010	0.020±0.006	5
TS-GE	0.0021±0.0004	0.016±0.001	4
TB-GE	0.0029±0.0006	0.015±0.002	4
CO	0.0068±0.0018	0.101±0.014	4
TS-CO	0.0085±0.0000	0.099±0.000	2
TB-CO	0.0062±0.0001	0.062±0.001	2
1 Agar	0.0028±0.0011	0.59±0.05	5
2 Gd	5.65±0.34	6.4±0.39	5

¹Agar relaxivity units: wt %⁻¹ s⁻¹

²Gd relaxivity units: mM⁻¹ s⁻¹