Dynamic contrast-enhanced magnetic resonance imaging and blood oxygenation level-dependent magnetic resonance imaging for the assessment of changes in tumor biology with treatment.

Functional magnetic resonance imaging (MRI) techniques are rapidly gaining importance as methods of exploring the pathophysiological properties of breast carcinomas. In the neoadjuvant setting where the primary tumor remains in situ, functional MRI is able to noninvasively evaluate microenvironmental features such as blood flow and oxygenation. Dynamic contrast-enhanced MRI provides information on tumor vascularity with evidence suggesting a role in predicting response to neoadjuvant chemotherapy. The spatial heterogeneity of response to anti-angiogenic and vascular disrupting agents can also be depicted. There is preliminary data supporting blood oxygenation level-dependent MRI as a potential marker of tumor oxygenation, with the ability to characterize tissue oxygenation changes with neoadjuvant chemotherapy. Additionally, advanced MR sequences such as diffusion-weighted MRI and MR spectroscopy have the potential to provide information relating to cellularity and metabolism, respectively.