123I-FP-CIT semi-quantitative SPECT detects preclinical bilateral dopaminergic deficit in early Parkinson's disease with unilateral symptoms.
OBJECTIVE
123I-FP-CIT SPECT has been successfully used to detect the loss of dopaminergic nigrostriatal neurons in Parkinson's disease at an early stage. In this study we evaluated the capacity of 123I-FP-CIT SPECT to assess bilateral dopamine transporter (DAT) loss in de-novo hemi-Parkinson's disease (PD) patients with one-sided clinical symptoms.


METHODS
Twenty-nine de-novo hemi-PD patients at an early stage (Hoehn & Yahr stage 1) and 18 gender and age matched healthy subjects were studied. SPECT imaging was always performed at 4 h post-injection. The ratios of striatal (S) to non-specific occipital (O) binding for the entire striatum (S/O), caudate nuclei (C/O), putamina (P(put)/O), and the putamen to caudate nucleus index (P(put)/C) were calculated in both the basal ganglia.


RESULTS
In PD patients S/O, C/O and P(put)/O ratio values contralateral to the clinically affected side were significantly lower (P<0.001) than in the control group (-38%, -34% and -42%, respectively). A significant reduction (P<0.001) of the striatal binding ratios was also found ipsilaterally (S/O, -31%; C/O, -28%; P(put)/O, -33%). The P(put)/C index was also bilaterally significantly reduced (P<0.01). DAT loss was significantly greater (P<0.001) in the contralateral than in the ipsilateral S; and putamen bilaterally presented a higher dopaminergic deficit than did caudate.


CONCLUSIONS
Our results indicate that semi-quantitative 123I-FP-CIT SPECT detects a bilateral dopaminergic deficit in early PD with unilateral symptoms and preclinical DAT loss in the ipsilateral striatal binding, corresponding to the side not yet affected by motor signs. Semi-quantitative analysis may thus be used to diagnose PD at an early stage as well as to identify individuals developing bilateral dopaminergic damage.
Filippi
Luca
L
Department of Biopathology and Diagnostic Imaging, University Tor Vergata, Rome, Italy.
Manni
Carlo
C
Pierantozzi
Mariangela
M
Brusa
Livia
L
Danieli
Roberta
R
Stanzione
Paolo
P
Schillaci
Orazio
O
D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology*; D002250:Carbon Radioisotopes; D016022:Case-Control Studies; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000473:pathology; D010300:Parkinson Disease / Q000175:diagnosis* / Q000473:pathology*; D011699:Putamen / Q000473:pathology; D011877:Radionuclide Imaging; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014326:Tropanes
D002250:Carbon Radioisotopes; D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493214:SLC6A3 protein, human; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane