Article Text

Molecular imaging in the diagnosis of Alzheimer's disease: visual assessment of [11C]PIB and [18F]FDDNP PET images


Objective To evaluate visual assessment of [11C]PIB and [18F]FDDNP PET images as potential supportive diagnostic markers for Alzheimer's disease (AD).

Methods Twenty-one AD patients and 20 controls were included. Parametric [11C]PIB and [18F]FDDNP global binding potential (BPND) images were visually rated as ‘AD’ or ‘normal.’ Data were compared with ratings of [18F]FDG PET images and MRI-derived medial temporal lobe atrophy (MTA) scores. Inter-rater agreement and agreement with clinical diagnosis were assessed for all imaging modalities. In addition, cut-off values for quantitative global [11C]PIB and [18F]FDDNP BPND were determined. Visual ratings were compared with dichotomised quantitative values.

Results Agreement between readers was excellent for [11C]PIB, [18F]FDDNP and MTA (Cohen kappa κ≥0.85) and moderate for [18F]FDG (κ=0.56). The highest sensitivity was found for [11C]PIB and [18F]FDG (both 1.0). The highest specificity was found for MTA (0.90) and [11C]PIB (0.85). [18F]FDDNP had the lowest sensitivity and specificity (0.67 and 0.53, respectively). The cut-off for quantitative [11C]PIB BPND was 0.54 (sensitivity and specificity both 0.95) and for [18F]FDDNP BPND 0.07 (sensitivity 0.80, specificity 0.73). Agreement between quantitative analyses and visual ratings was excellent for [11C]PIB (κ=0.85) and fair for [18F]FDDNP (κ=0.40).

Conclusion Visual assessment of [11C]PIB images was straightforward and accurate, showing promise as a supportive diagnostic marker for AD. Moreover, [11C]PIB showed the best combination of sensitivity and specificity. Visual assessment of [18F]FDDNP images was insufficient. The quantitative analysis of [18F]FDDNP data showed a considerably higher diagnostic value than the visual analysis.

  • Alzheimer's disease
  • PET, ligand studies

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.