BraTS 2018 is a dataset which provides multimodal 3D brain MRIs and ground truth brain tumor segmentations annotated by physicians, consisting of 4 MRI modalities per case (T1, T1c, T2, and FLAIR). Annotations include 3 tumor subregions—the enhancing tumor, the peritumoral edema, and the necrotic and non-enhancing tumor core. The annotations were combined into 3 nested subregions—whole tumor (WT), tumor core (TC), and enhancing tumor (ET). The data were collected from 19 institutions, using various MRI scanners