Combined Look-Locker Arterial Spin Labeling (ASL) and Intrinsic R2*susceptibility Response to Vascular Disruption in a Clinically Relevant Liver Metastatic Model of Colorectal Carcinoma

Sean Peter Johnson¹, Rajiv Ramasawmy², Adrienne Campbell², Mathew Robson¹, Mario Mazzantini¹, Vineeth Rajkumar¹, Barbara Pedley¹, Mark Lythgoe², Simon Walker-Samuel²

Liver metastases are the major cause of mortality in patients with colorectal carcinoma (CRC). The vascular disrupting agent OXi4503 has been tested in phase I clinical trials of metastatic disease with R2* recommended as a biomarker of response. R2* response however may not accurately reflect response to treatment exclusively. Arterial spin labeling (ASL) is able to assess changes in tumour perfusion. We show that in a clinically relevant liver metastatic model of CRC (n=10 metastases) acquisition of combined R2* and ASL at baseline and 90min following 40mg/kg OXi4503 i.v. is more adequate at assessing response to treatment.