Transient globus pallidus T1 shortening associated with polycythaemia and dystonia.

We report a child who concurrently developed polycythaemia, dystonia, and T1 shortening in the globus pallidus, medial cerebral peduncle and superior cerebellar peduncles on MRI. With spontaneous resolution of the polycythaemia after about 2 1/2 years, the dystonia and MRI abnormalities also resolved. Although the physiological cause of the T1 shortening is not known, this appears to be another cause of T1 shortening in the basal ganglia.