What condition is characterized by the "Eye of Tiger" sign on MRI?

The condition characterized by the "Eye of Tiger" sign on MRI is Pantothenate kinase-associated neurodegeneration (PKAN). This condition is a form of neurodegeneration with brain iron accumulation (NBIA) and is caused by mutations in the PANK2 gene. The "Eye of Tiger" sign is observed on T2-weighted MRI scans and is due to specific changes in brain structures, particularly in the globus pallidus, which can be visualized as a characteristic rim of high signal intensity around a central darker area, resembling a tiger's eye.

In PKAN, the accumulation of iron in the basal ganglia results in the distinctive imaging appearance. This finding is important in aiding clinical diagnosis, especially when combined with the neurological symptoms typically seen in patients with PKAN, such as movement disorders and cognitive decline. The recognition of this MRI finding can assist clinicians in differentiating PKAN from other disorders that may present with similar symptoms but lack this specific imaging hallmark.