Metastatic Colorectal Cancer: Treatment Response With Dynamic Contrast MRI

This study will investigate the use of projection reconstruction dynamic contrast-enhanced MRI (DCE-MRI) as a surrogate marker of tumor vascularity in patients treated with the antiangiogenic agent bevacizumab. DCE-MRI is gaining popularity as a method to assess the functional response of tumors to agents targeting the vascular endothelial growth factor (VGEF) pathways. DCE-MRI measurements have been proposed as a non-invasive measure of both tumor biologic activity and (in the case of antivascular therapy) early response to treatment. A number of phase I and II studies demonstrate the ability for DCE-MRI to detect perfusion changes associated with tumor biologic response to vascularly targeted agents. It has been suggested that pre-treatment DCE-MRI might identify tumors with high intrinsic perfusion and that these tumors will be more likely to respond to antivascular-based therapies. However, the current use of DCE-MRI in clinical settings is challenging. Trade-offs between spatial coverage, time, and spatial resolution make this technique difficult to implement in human studies and may limit its reliability. The use of projection reconstruction-based acquisition can mitigate the need for these trade-offs and can simultaneously provide high temporal and spatial resolution data for DCE-MRI analysis.