Intratumor Heterogeneity of Perfusion and Diffusion in Clear Cell Renal Cell Carcinoma: Correlation with Tumor Cellularity

Abstract Background Magnetic Resonance Imaging (MRI) has the potential to non-invasively inform about tumor micro-environment. A correlation between arterial spin labelled (ASL) MRI and tumor vasculature has been previously demonstrated, however, its correlation with tumor cellularity is unknown. Purpose To assess intratumor heterogeneity of perfusion and diffusion in vivo in clear cell renal cell carcinoma (ccRCC) using MRI, and correlate these findings with tumor vascularity and cellularity at histopathology. Patients and Methods 23 ccRCC patients underwent ASL and diffusion-weighted MRI prior to surgery after signing an informed consent in this prospective IRB-approved, HIPAA-compliant study. Quantitative ASL perfusion and diffusion were measured in two areas within the same tumor with high and low perfusion. Microvessel density (MVD) on CD31 and CD34 immunostains and tumor cellularity in anatomically co-registered tissue samples were correlated to MRI measurements (Spearman; P