Koivunen J, Scheinin N, Virta JR, Aalto S, Vahlberg T, Nagren K, Helin S, Parkkola R, Viitanen M, Rinne JO.
PET imaging of beta-amyloid deposition in patients with mild cognitive impairment: a two year follow-up study.
Human Amyloid Imaging 2011 Meeting Abstracts. 2011 Jan 15;
Background: Patients with amnestic mild cognitive impairment (MCI) have greater risk of conversion to AD.
Increased brain amyloid burden in AD and MCI has been demonstrated with PET using [11C]PIB as a tracer.
Objective: To evaluate change in beta-amyloid deposition in with MCI during 2 year follow-up.
Methods: MCI patients and controls were studied with [11C]PIB PET, MRI and neuropsychometry at baseline and
these investigations were repeated in MCI patients after follow-up.
Results: Those MCI patients converting to AD during follow-up had greater [11C]PIB retention in the posterior
cingulate (p = 0.020), in the lateral frontal cortex (p = 0.006), in the temporal cortex (p=0.022), in the putamen
(p = 0.041) and in the caudate nucleus (p=0.025) as compared to non-converters. In converters there was no
significant change in [11C]PIB uptake, whereas an increase was seen as compared to baseline in non-converters
in the anterior and posterior cingulate, temporal and parietal cortices and in the putamen. Hippocampal atrophy
was greater in converters at baseline than in non-converters, but increased significantly in both groups during
Conclusions: Hippocampal atrophy and amyloid deposition seem to dissociate during the evolution of MCI, the
atrophy increasing clearly and [11C]PIB retention changing modestly when conversion to AD occurs. Longer followup
is needed to determine whether non-converters would convert to AD later, which would suggest accelerated
[11C]PIB retention preceding clinical conversion.