Susceptibility-weighted MR imaging (SWI) has become a non-invasive diagnostic modality for functional MR imaging (fMRI) of the brain and also for the imaging of tumors, injuries, malformations or microhemorrhages. SWI often enables detection of otherwise subtle abnormalities or provides additional relevant information when combined with routine MR imaging. The purpose of this article is to illustrate the potential of SWI in the discrimination of paramagnetic and diamagnetic brain lesions in neuroradiological applications.