Study: PIB holds promise for Alzheimer's diagnosis

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Visual assessment of 11C-PIB images showed the best combination of sensitivity and specificity and holds promise as a supportive diagnostic marker for Alzheimer's disease (AD), according to a study published June 11 in the Journal of Neurology, Neurosurgery and Psychiatry.
 
The study included 21 patients with AD and 20 controls. Researchers visually rated parametric 11C-PIB and 18F-FDDNP global binding potential images as 'AD' or 'normal.'

Nelleke Tolboom, PhD candidate from the department of nuclear medicine and PET research at the VU University Medical Centre in Amsterdam, and colleagues compared data with ratings of 18F-FDG PET images and MRI-derived medial temporal lobe atrophy scores.

Inter-rater agreement and agreement with clinical diagnosis were assessed for all imaging modalities and agreement between readers was excellent for 11C-PIB, 18F-FDDNP and MRI-derived medial temporal lobe atrophy scores and moderate for 18F-FDG, according to the authors.

Tolboom and colleagues found the highest sensitivity for 11C-PIB and 18F-FDG (both 1.0). The highest specificity was found for medial temporal lobe atrophy  score (0.90) and 11C-PIB (0.85) while 18F-FDDNP had the lowest sensitivity and specificity (0.67 and 0.53, respectively).

The cut-off for quantitative 11C-PIB global binding potential was 0.54 (sensitivity and specificity both 0.95) and for 18F-FDDNP global binding potential 0.07 (sensitivity 0.80, specificity 0.73).

Visual assessment of 11C-PIB images was straightforward and accurate and showed the best combination of sensitivity and specificity, concluded Tolboom and colleagues.