Analysis of cerebral magnetic resonance images of 24 subjects with Syd
enham's chorea and 48 age-, height-, weight-, gender-, and handedness-
matched controls demonstrated increased sizes of the caudate, putamen,
and globus pallidus in the Sydenham's chorea group. In contrast, neit
her total cerebral, prefrontal, or midfrontal volumes or thalamic area
were increased. These results indicate the selective involvement of t
he basal ganglia in Sydenham's chorea.