Advertisement

HIGH PUTAMEN 11C-PIB RETENTION IN MCI IS ASSOCIATED WITH AN INCREASED RISK OF CONVERSION TO AD

      Background: Alzheimer's disease (AD) pathology has most likely been ongoing in brain years before onset of cognitive symptoms. The challenge is to detect the disease in its early stages and to be able to predict among patients who have the disease who will develop mild cognitive impairment (MCI) and convert to AD. High fibrillar Aβ deposition in the cerebral cortex has been well established by 11 C-PiB-PET in MCI and AD patients. Furthermore, a high 11 C-PiB-PET retention was demonstrated in the striatum of PSN1 mutations carriers but is less studied in sporadic AD/MCI. The aim was to study the predictive value of high 11 C-PiB-PET retention in the striatum of MCI patients.
      Methods: We compared the caudate, putamen and neocortical 11 C-PiB-PET retention in 97 AD, 72 MCI patients, (mean age=68 ys). This population of patients was recently reported in a European multicenter imaging study (Nordberg et al. 2013).
      Results: In the evaluations we focused on the putamen as we found that the putamen 11 C-PiB retention exceeded the caudate 11 C-PiB retention in all subjects (p<0.001). No significant differences were found in the putamen 11 C-PiB retention between AD and MCI 11 C-PiB-positive patients. MCI patients, who converted to AD within 2 years, showed significantly higher 11 C-PiB retention in the putamen in comparison with the neocortex (p =0.006) while the MCI non-converting patients showed no significant differences between the two regions (p =0.15). These regional differences became somewhat less marked when compared MCI PiB-positive MCI converters (p =0.006) compared to MCI PIB-positive non-converters to AD (p =0.046).
      Conclusions: High putamen 11 C-PiB retention in MCI patients is associated with an increased risk of conversion to AD.