[123I]IPT binding to the presynaptic dopamine transporter: variation of intra- and interobserver data evaluation in parkinsonian patients and controls

Eur J Nucl Med. 2000 Dec;27(12):1809-12. doi: 10.1007/s002590000384.


Imaging the presynaptic dopamine transporter with cocaine analogues and single-photon emission tomography (SPET) has proven to be a potential diagnostic tool for classifying the extent and degree of dopaminergic nerve cell loss. For correct interpretation of scan results, however, knowledge of the intra-/interobserver variation of data evaluation is mandatory. Iodine-123 labelled N-(3-iodopropen-2-yl)-2beta-carbomethoxy-3beta-(chlorophenyl)tropane ([123I]IPT) SPET data of 10 controls and 30 parkinsonian patients with varying degrees of reduced IPT binding were analysed twice by an expert (intraobserver) and once by a less experienced physician in training (interobserver). For semiquantitative evaluation of specific IPT binding, ratios between total striatum, caudate and putamen and a background region were calculated. No significant differences were observed for either the intra- or the interobserver analyses. Variation was lower in controls than in the patient group. Overall variation indices were below 5%. Variation in interobserver results was only slightly higher than that in intraobserver results. The intra-/interobserver results showed highly significant correlations (r = 0.99). The intraclass correlation was higher than 0.9 for all evaluations. Our results indicate that the specific presynaptic striatal dopamine transporter binding assessed with IPT-SPET may be reproducibly analysed by the same and different observers in controls as well as in patients with varying degrees of reduced binding.

MeSH terms

  • Carrier Proteins / metabolism*
  • Dopamine Plasma Membrane Transport Proteins
  • Humans
  • Iodine Radioisotopes
  • Membrane Glycoproteins*
  • Membrane Transport Proteins*
  • Neostriatum / diagnostic imaging
  • Nerve Tissue Proteins / metabolism*
  • Observer Variation
  • Parkinson Disease / diagnostic imaging*
  • Parkinson Disease / microbiology*
  • Radiopharmaceuticals*
  • Receptors, Presynaptic / metabolism*
  • Tomography, Emission-Computed, Single-Photon
  • Tropanes*


  • Carrier Proteins
  • Dopamine Plasma Membrane Transport Proteins
  • Iodine Radioisotopes
  • Membrane Glycoproteins
  • Membrane Transport Proteins
  • Nerve Tissue Proteins
  • Radiopharmaceuticals
  • Receptors, Presynaptic
  • Tropanes
  • N-(3-iodopropen-1-yl)-2-carbomethoxy-3-(4-chlorophenyl)tropane