MRI using ferumoxytol quantifies changes of pancreatic tumor microenvironment that predicts effect of immune therapy

Motivation: To develop a noninvasive MRI based approach for monitoring the tumor microenvironment (TME). Goal(s): To assess changes in vascular volume fraction (VVF) and tumor associated macrophages (TAM) as measures of TME. Approach: We measured VVF and TAM (by changes in T2 and T2*) at baseline and following therapy using ferumoxytol in a murine model of pancreatic cancer (PDAC). We performed a preclinical trial with an immune modulatory agent. Results: We saw a statistically significant difference in tumor growth and changes of VVF and TAM with immune modulation. Impact: We have developed a method of monitoring the PDAC TME with possibilities of human translation.