Sydenham chorea: MR manifestations in two cases.

The acute onset of a unilateral choreiform movement dis­ order in a child with a recently documented febrile illness or streptococcal pharyngitis is suggestive of Sydenham chorea. The MR manifestations of two clinically corroborated cases of Sydenham chorea are summarized. Increased signal inten­ sity in the corpus striatum contralateral to the patients' symp­ tomatic side was observed on T2-weighted images. Focal enhancement in the involved head of the caudate was iden­ tified after IV administration of gadopentetate dimeglumine. The MR findings correlated with anatomic regions , which have been described to be susceptible to cross reaction with lgG antibodies that are formed in association with streptococcal infection.