Contrast issues in brain tumor imaging.

The utility of gadolinium-based MR imaging contrast agents and iodinated CT contrast agents is discussed in the context of brain tumor imaging. Although contrast materials are routinely administered for brain tumor imaging to improve lesion conspicuity and characterization, the optimal dose and imaging protocols vary according to lesion type and location, the specific clinical situation, and the imaging equipment that is available. Special problems may be encountered in contrast-enhanced imaging of patients with brain tumors who have undergone treatment with surgery, radiation, or chemotherapy.