The purpose of this study is to see whether magnetic resonance (MR) techniques can detect changes caused by chemotherapy in the livers of patients who have been treated for colorectal cancer. Some patients who undergo chemotherapy for colorectal cancer may experience side-effects in their livers. These side effects may influence further treatment options. If this study finds that MR techniques detect changes in the liver due to chemotherapy, then MR methods may eventually be used to help patients and physicians plan further treatment.