Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system characterized by heterogeneous clinical presentations and variable disease course. Magnetic resonance imaging (MRI) has long been central to MS diagnosis, primarily through the demonstration of dissemination in space (DIS) and dissemination in time (DIT).The 2024 revision of the McDonald criteria represents a major conceptual shift by integrating advanced imaging markers, biological biomarkers, and optic nerve assessment into a unified diagnostic framework, aiming to improve early diagnosis while reducing misdiagnosis.