Using high-field MRI, we investigated possible morphologic changes in the basal ganglia of 22 patients with clinically diagnosed idiopathic spasmodic torticollis (iTs) compared with 28 age-matched normal controls. Two patients were found to have distinct basal ganglia lesions and were excluded from further analysis. The frequency of gross morphologic changes (atrophy, enlarged Virchow-Robin spaces) in patients was not significantly higher than in controls. However, T2 values calculated for the putamen and pallidum on both sides were significantly higher in the lentiform nucleus of the patients compared with the controls. In contrast, other well-defined subcortical regions did not exhibit a similar abnormality, nor did the optical or quantified signal analysis of various regions of interest show any differences. This finding suggests a morphologic abnormality in iTs that is not associated with a gross structural lesion. It could reflect focal gliosis and might correspond to earlier sporadic pathoanatomic descriptions of gliosis in idiopathic dystonia.