123I-FP-CIT semi-quantitative SPECT detects preclinical bilateral dopaminergic deficit in early Parkinson's disease with unilateral symptoms

Nucl Med Commun. 2005 May;26(5):421-6. doi: 10.1097/00006231-200505000-00005.


Background and aim: 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.

Patients and 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.

Conclusion: 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.

MeSH terms

  • Adult
  • Aged
  • Brain / pathology*
  • Carbon Radioisotopes*
  • Case-Control Studies
  • Dopamine Plasma Membrane Transport Proteins
  • Female
  • Humans
  • Iodine Radioisotopes*
  • Male
  • Membrane Glycoproteins / metabolism
  • Membrane Transport Proteins / metabolism
  • Middle Aged
  • Nerve Tissue Proteins / metabolism
  • Neurons / pathology
  • Parkinson Disease / diagnosis*
  • Parkinson Disease / pathology*
  • Putamen / pathology
  • Radionuclide Imaging
  • Time Factors
  • Tomography, Emission-Computed, Single-Photon / methods*
  • Tropanes*


  • Carbon Radioisotopes
  • Dopamine Plasma Membrane Transport Proteins
  • Iodine Radioisotopes
  • Membrane Glycoproteins
  • Membrane Transport Proteins
  • Nerve Tissue Proteins
  • SLC6A3 protein, human
  • Tropanes
  • 2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane