Dopamine D2 receptor binding is reduced in Wilson's disease: correlation of neurological deficits with striatal 123I-iodobenzamide binding.

To visualise and quantify dopamine D2 receptor binding in the corpus striatum of patients with neurological Wilson's disease (WD) 123I-Iodobenzamide (IBZM) binding was measured using single photon emission computer tomography (SPECT). Ratios of striatal to frontal countrates were calculated in 8 patients and in 21 healthy control subjects. We found reduced IBZM binding ratios in all patients with WD in comparison to those in controls (1.48 +/- 0.13 vs. 1.73 +/- 0.09). The reduction in IBZM binding was correlated with the overall severity of neurological deficits and the severity of dysarthria (correlation coefficients -0.86 [p < 0.01] and -0.79 [p < 0.01], respectively). When patients of three different subgroups of neurological WD were compared no differences in IBZM binding were found. We conclude that assessing basal ganglia function in vivo using IBZM-SPECT is a valuable diagnostic tool in WD.