Imaging of dopamine transporters with iodine-123-beta-CIT and SPECT in Parkinson's disease.
The aim of the present study was to demonstrate the degeneration of the dopaminergic nigrostriatal pathway in Parkinson's disease by using the cocaine derivative [123I]beta-CIT (2-beta-carbomethoxy-3-beta(4-iodophenyl)-tropane or RTI-55) and SPECT and to relate the findings to the severity of the disease (Hoehn and Yahr scale, H/Y) and to clinical data such as motor score and activities of daily living.


METHODS
Thirteen volunteers and 47 patients with idiopathic Parkinson's disease (PD) of H/Y Stage I-V (I:n = 16, II:n = 6, III:n = 14, IV:n = 9, V:n = 2) were investigated. Acquisitions were performed 2, 4, 16, 20 and 24 hr postinjection. ROIs were drawn over the striatum and the cerebellum. Specific beta-CIT binding was defined as striatal minus cerebellar binding. The ratio of specific over nondisplaceable binding (striatum/cerebellum-1) was determined as well as the percent deviation of this ratio from age-expected control values.


RESULTS
The time-activity curve of striatal [123I]beta-CIT binding demonstrated a maximum around 20 hr postinjection in controls and a peak 4 hr postinjection in PD patients. Ratios differed significantly between the two groups. A significant correlation existed between this ratio and clinical measures. Hemiparkinsonian patients revealed significantly diminished [123I]beta-CIT binding not only contralateral to the clinically affected but also contralateral to the clinically unaffected side. [123I]beta-CIT binding showed a significant decrease in comparison to age-expected values ranging from 36% in H/Y stage 1 to 71% in H/Y stage V.


CONCLUSIONS
The present study demonstrates that it is possible to visualize and quantify the degeneration of dopaminergic nigrostriatal neurons in PD using [123I]beta-CIT and SPECT with good correlation to clinical parameters.
Asenbaum
S
S
Department of Neurology, University of Vienna, Austria.
Brücke
T
T
Pirker
W
W
Podreka
I
I
Angelberger
P
P
Wenger
S
S
Wöber
C
C
Müller
C
C
Deecke
L
L
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002352:Carrier Proteins / Q000378:metabolism*; D003042:Cocaine / Q000031:analogs & derivatives*; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010300:Parkinson Disease / Q000000981:diagnostic imaging*; D017661:Receptors, Presynaptic / Q000378:metabolism*; D015899:Tomography, Emission-Computed, Single-Photon
D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D017661:Receptors, Presynaptic; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D003042:Cocaine