Response of TH-MYCN model of neuroblastoma to cyclophosphamide (CPM). a) Relative changes in tumor volume and native T1 over 48h in tumor-bearing TH-MYCN mice following treatment with vehicle or 25mg/kg CPM. Normalized data are presented as mean ± 1 standard error of the mean (n=5), with any significant differences between control and CPM-treated cohort indicated (*p<0.05, **p<0.01, ***p<0.005, Student’s 2-tailed unpaired t-test, and *♮p<0.02, **♮p<0.003, ***♮p<0.0002, Student’s 2-tailed unpaired t-test with a Bonferroni correction (n=3)). b) Parametric T1 maps of tumor-bearing TH-MYCN mice acquired prior to and 48h following treatment with vehicle or 25mg/kg CPM.