Schematic illustration of semiquantitative scoring system for subchondral bone marrow edema-like lesions and subchondral cysts using the Whole Organ Magnetic Resonance Imaging Score (WORMS). a: Scoring of subchondral bone marrow edema-like lesions. The score is based on the extent of regional marrow involvement by areas of free water signal with ill-defined margins. b: Scoring of subchondral cysts. The score is based on the extent of focal bone loss through individual cysts (illustrated in the central region) or multiple cysts (illustrated in the posterior region) subchondrally.