ABSTRACT
This chapter considers the use of one imaging modality, magnetic resonance imaging (MRI), as a biomarker for drug development with a focus on MRI biomarkers that have been translated successfully between preclinical and clinical studies. Imaging offers a number of biomarkers that can provide information about genetic, biochemical, physiological, and anatomic processes in the tissue of interest. The tumor contrast agent concentration is inferred from the magnitude of the signal change and parameters reflecting the underlying vascular physiology are derived using various analytical approaches. The change in signal over time measured by dynamic contrast MRI (DCE-MRI) reflects the exchange of contrast agent between the vasculature and, since the contrast agent does not penetrate viable cells, interstitial space. DCE-MRI, which employs a commonly used contrast agent, has been implemented in preclinical and clinical studies to quantify the effects of antivascular agents on the tumor blood supply within hours to days after the start of treatment.
