Figure 5.

SBK2-Lys-(Gd-DOTA) shows prolonged labeling of intracranial CNS-1 tumors at 0.2mmol Gd/kg compared to Scrambled-Lys-(Gd-DOTA). (A) The rate of agent clearance from 7 d CNS-1 tumors was determined by the change in T₁ map value/time (min) from 20 to 35 min following intravenous injection of agent and is significantly different (p=0.026) between the mice treated with SBK2 and Scrambled agent. N=4 for each agent. (B) Normalized T₁ map values over time for mice administered the indicated agent at 0.2mmol Gd/kg in CNS-1 intracranial tumor (top) or a contralateral control area (bottom). The agents were injected following acquisition of 5 baseline scans. Upon injection, the T₁ map values decrease at a similar rate and to a similar extent but the SBK2 agent is cleared more slowly than the Scrambled agent in tumor. The lines show the mean +/− SE of 4 mice treated with SBK2 agent, and 4 mice treated with Scrambled agent. SBK2 and Scrambled agent show the same trend observed with flank tumors. The decrease in T₁ signal is less pronounced in brains compared to flanks, despite twice the dose.