Brain MR images in a 20-year-old woman. (a) Axial T2-weighted image shows a hyperintense mass with concentric pattern in the right centrum semiovale. (b) Axial T1-weighted image reveals hypoisointense concentric rings in the white matter of the right parietal lobe. (c) Axial T1-weighted image after contrast shows concentric enhancing rings. (d) Axial T2-weighted image, 1 month after therapy, shows differences with decrease of the signal intensity at the center of the lesion. (e, f) Coronal T1-weighted image after administration of gadolinium demonstrates a low-signal, non-enhancing lesion.