title: [Dopamine (D2) receptor SPECT with 123I-iodobenzamide (IBZM) in diagnosis of Parkinson syndrome].
abstract: For effective drug therapy of Parkinson's syndrome (PS), it is necessary to distinguish between idiopathic and secondary genesis and PS in neuronal systemic degeneration. [123I]Iodobenzamide ([123I] IBZM) is a radiolabelled benzamide and binds specifically to the cerebral dopamine receptor (D2) in the basal ganglia. The purpose of this study was to determine the value of the [123I]IBZM D2-receptor SPECT in the differential diagnosis of PS. A total of 38 patients (20 females, 18 males; age 61 +/- 13.3 years), with typical extrapyramidal symptoms were investigated. Twenty suffered from idiopathic and 11 from secondary PS. Seven patients in whom a neurological disease could be excluded, served as controls. SPECT data were acquired 90 min after i.v. injection of 185-200 MBq [123I]IBZM. After reconstruction with a Butterworth filter (cutoff frequency 0.5) and attenuation correction (coefficient 0.12 cm(-1)) we quantify the IBZM basal ganglia uptake as ratio to teh frontal D2-receptor-free cortex (BG/FC). The patients with idiopathic PS (IPS) and the controls revealed high and specific IBZM uptake in the basal ganglia compared to the adjacent frontal brain tissue (IPS: BG/FC = 1.44 +/- 0.10; controls: BG/FC = 1.48 +/- 0.10). A significant decreased striatal IBZM uptake is found in cases with secondary PS (BG/FC = 1.25 +/- 0.10; p<0.0001, t-test compared to controls and IPS). The patient group with IPS can be subdivided into patients without L-dopatherapy (BG/FC = 1.49 +/- 0.07), patients with longstanding L-dopa-therapy demonstrating significantly decreased striatal IBZM uptake (BG/FC = 1.31 +/- 0.04; p<0.0001, t-test compared to controls and other IPS), which correlates pathophysiological with a reduction of free D2 receptors, and patients with de novo PS showing a slight increased striatal IBZM uptake (BG/FC = 1.56 +/- 0.05), which represents D2-receptor stimulation. [123I]IBZM-SPECT is a sensitive and non-invasive test for striatal D2-receptor density and activity which permits relatively clear discrimination between idiopathic and secondary PS and yields important information for differential therapy.
authors.affiliation: Institut für Neuroradiologie, Universität des Saarlandes, Homburg/Saar.
authors.forename: W
authors.initials: W
authors.lastname: Reiche
authors.forename: M
authors.initials: M
authors.lastname: Grundmann
authors.forename: G
authors.initials: G
authors.lastname: Huber
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001549:Benzamides; D003937:Diagnosis, Differential; D018492:Dopamine Antagonists; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D009410:Nerve Degeneration / Q000502:physiology; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D010302:Parkinson Disease, Secondary / Q000000981:diagnostic imaging / Q000503:physiopathology; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2 / Q000502:physiology*; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D001549:Benzamides; D018492:Dopamine Antagonists; D007457:Iodine Radioisotopes; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2; C055743:3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide
vernacular_title: Die Dopamin(D2)-Rezeptor-SPECT mit 123I-Jodbenzamid (IBZM) in der Diagnostik des Parkinson-Syndroms.