MR molecular imaging of tumor vasculature and vascular targets.

Tumor angiogenesis and the ability of cancer cells to induce neovasculature continue to be a fascinating area of research. As the delivery network that provides substrates and nutrients, as well as chemotherapeutic agents to cancer cells, but allows cancer cells to disseminate, the tumor vasculature is richly primed with targets and mechanisms that can be exploited for cancer cure or control. The spatial and temporal heterogeneity of tumor vasculature, and the heterogeneity of response to targeting, make noninvasive imaging essential for understanding the mechanisms of tumor angiogenesis, tracking vascular targeting, and detecting the efficacy of antiangiogenic therapies. With its noninvasive characteristics, exquisite spatial resolution and range of applications, magnetic resonance imaging (MRI) techniques have provided a wealth of functional and molecular information on tumor vasculature in applications spanning from "bench to bedside". The integration of molecular biology and chemistry to design novel imaging probes ensures the continued evolution of the molecular capabilities of MRI. In this review, we have focused on developments in the characterization of tumor vasculature with functional and molecular MRI.