COMPARISON OF TRANSCRANIAL SONOGRAPHY, MAGNETIC-RESONANCE-IMAGING, AND SINGLE-PHOTON EMISSION COMPUTED-TOMOGRAPHY FINDINGS IN IDIOPATHIC SPASMODIC TORTICOLLIS

Various lines of evidence suggest that the basal ganglia and thalamus are involved in the pathogenesis of idiopathic dystonia, but unfortuna tely neuroradiological and pathological data are sparse and controvers ial. In this study, we have examined 10 patients with spasmodic tortic ollis by neuroimaging techniques, including transcranial sonography (T S; n = 10), conventional (n = 10) and diffusion-weighted (n = 5) magne tic resonance imaging (MRI), and single photon emission computed tomog raphy (SPECT; n = 10), employing [I-123]iodobenzamide (IBZM) as a liga nd with a high affinity to the D2 receptor. In seven patients, TS show ed small hyperechogenic lesions in the medial segments of the lentifor m nucleus contralateral to the side of head deviation. In accordance w ith the site of TS abnormalities, diffusion-weighted MRI displayed a h yperintense lesion in only one patient, while standard MRI of this are a was normal in all patients. SPECT revealed a slight but statisticall y nonsignificant reduction of IBZM tracer uptake in an area cor respon ding to the dorsal portions of the striatum in 9 of the 10 patients. T S findings support the hypothesis that structural alterations of the p allidothalamic circuit contralateral to the side of head deviation are involved in the pathogenesis of idiopathic spasmodic torticollis. TS may be more sensitive in detecting basal ganglia alterations than MRI.