Fig 2.

Early MR imaging changes in the globus pallidus. The linear T2-hyperintensity that streaks along the medial border of the GP is the earliest T2 change (A, arrowhead). The round center in the anteromedial aspect is first observed at 3 years of age (B, left). Subtle hypointensity is also detected on the susceptibility-weighted image (B, right). In patients with serial MRIs (C and D), iron-related hypointensity becomes definitely evident by 4 years of age with the appearance of an isolated T2-hyperintense center (C). The surrounding areas decrease in signal intensity with age (D). P8 and P9 indicate the number of patients in the On-line Table; m., months of age; y., years of age.