SPET investigations in extrapyramidal diseases using specific ligands

Single photon emission tomographic investigations of the extrapyramidal system have become easier to perform since the development of the ligands [123I]-beta-CIT and [123I]-IBZM. Thirty-three patients were investigated with [123I]-IBZM. The images were evaluated visually and semi-quantitatively (ratio of the striatum to front cortex). Ten controls showed a mean (+/- S.D.) ratio of 1.513 +/- 0.06; nine patients with Parkinson's disease had a smaller ratio of 1.425 +/- 0.095; six patients with Huntington's disease had a significantly lower ratio (1.147 +/- 0.105). Eight patients were not classified, because of different nosologic entities. Twenty-three patients were investigated with [123I]-beta-CIT. They were evaluated using standard techniques and the ratio of the striatum to cerebellum. Six controls had a mean ratio of 5.128 +/- 0.787. In 11 Parkinson patients, the ratio was significantly less (3.359 +/- 0.769). Patients with focal dystonia showed normal values. One patient with Huntington's disease had a significantly lower ratio. Receptor studies of the extrapyramidal system may help with diagnoses and could be of relevance therapeutically.