I-123 IBZM SPECT - RECONSTRUCTION METHODOLOGY AND RESULTS IN PARKINSONISM AND DYSTONIA

In 58 patients with Parkinsonism or dystonia striatal dopamine D2 rece ptors were investigated using I-123-iodobenzamide (I-123-IBZM) single- photon emission computed tomography (SPECT). The influence of SPECT re construction methodology on semiquantification and the clinical value of I-123-IBZM SPECT were evaluated. Delineation of the striatal uptake and striatum/frontal cortex (ST/FC) ratios were improved by the use o f compensation procedures for scatter and attenuation as well as the c hoice of an adequate filter. Satisfactory results were achieved using a Metz prefilter with a comparatively high order number (i.e. high cut -off and low suppression of higher frequencies via roll-off). Regardin g clincal diagnoses it was not possible to differentiate between advan ced idiopathic Parkinson's disease (IP) and Parkinsonism of other aeti ology (OP) on the basis of I-123-IBZM SPECT. But patients with IP and favourable response to L-Dopa showed significantly higher ST/FC ratios than those with fluctuating response. In patients with dystonia ST/FC ratios were significantly higher compared to patients with IP or OP.