Pre-clinical animal models of spontaneous metastatic cancer are infrequent; the few that exist are resource intensive because determination of the presence of metastatic disease, metastatic burden, and response to therapy normally require animal sacrice and extensive pathological examination. We recently identied and characterized a patient derived xenograft model with metastatic potential, bladder xenograft BL0293, developed by Jackson Laboratories and the University of California at Davis. In this study we performed a detailed imaging characterization of this model, which develops spontaneous liver and bone metastases. Using non-contrast T2 weighted MRI, hepatic metastases were demonstrated in over 70% of animals at 52 days post tumor implantation without resection of the xenograft and in 100% of animals at day 52 following resection of the xenograft. T2w turbo spin echo (T2wTSE) sequence was applied in the coronal view with a repetition time (TR) 5333ms, echo time (TE) 65ms, with an in-plane pixel of 0.180 × 0.180 mm2. A Spectral Presaturation with Inversion Recovery (SPIR) sequence (Philips Healthcare, Best, The Netherlands) was used to suppress the fat component and assist in distinguishing fat from cystic mass and tumor tissue. In a group of animals receiving one cycle of effective chemotherapy (Temozolomide; (50 mg/kg; PO, QDx5)] plus [(veliparib, a poly (ADP-ribose) polymerase inhibitor) (7.75 mg/kg; PO; BIDx7)]), no animals demonstrated metastasis by imaging. The imaging characteristics of this model, which is available from the National Cancer Institute Patient-Derived Models Repository (https://pdmr.cancer.gov/), is highly favorable for preclinical research studies of metastatic disease when used in conjunction with non-contrast T2 weighted MRI. | 
