Comparison of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) with gadofosveset trisodium (Vasovist, Schering, Berlin, Germany) to gadopentetate dimeglumine (GD-DTPA, Magnevist, Schering) in the assessment of response to neo-adjuvant treatment with bevacizumab (Avastin) of liver meta

Primary objectives: To assess the objective response by DCE-MRI with Vasovist and Magnevist of bevacizumab when combined with chemotherapy regimens as first line treatment of metastatic colorectal cancer.
Primary endpoints: Tumor response to neo-adjuvant treatment with bevacizumabSurvivalResults of VEGF/COX-2 ratio and measurements with DCE-MRI and PET/CT