The different faces of central nervous system metastases

Cerebral metastases are the commonest central nervous system tumors. The MR assessment should include T1-weighted images with and without enhancement and T2/FLAIR images. They usually appear as multiple lesions with nodular or annular enhancement and are surrounded by edema. They are hypervascularized and have no restriction of their diffusion coefficient in their necrotic area and contain lipids on 1H spectroscopy. Metastases can be distinguished from primary tumors by the lack of malignant cell infiltration around the tumor. Stereotactic radiotherapy may temporarily increase tumor volume, although this is not of adverse oncological value. Less commonly, spinal disease may be asymptomatic and should be examined by MR.