The Usefulness of Amyloid Imaging in Predicting the Clinical Outcome After Two Years in Subjects with Mild Cognitive Impairment
Timo Grimmer, Carolin Wutz, Alexander Drzezga, Stefan Förster, Hans Förstl, Marion Ortner, Robert Perneczky and Alexander Kurz
Affiliation: Department of Psychiatry and Psychotherapy, Klinikum rechts der Isar, Technische Universität München, Möhlstr. 26, 81675 München, Germany
Background: Mild cognitive impairment (MCI) is a syndrome heterogeneous with regards to etiology and
prognosis. Amyloid imaging enables to visualize a hallmark pathology of Alzheimer’s disease (AD). Therefore we aimed
to assess the usefulness of [11C]PiB PET for predicting clinical outcome of MCI patients after an interval of 2 years.
Methods: In 28 MCI participants with a global CDR rating at baseline of 0.5 a baseline examination including clinical assessments
and [11C]PiB PET imaging and a clinical follow-up examination after a planned interval of 24 months were performed.
Predictive values and accuracy of amyloid-positive and negative scans for conversion to dementia of any type and
to dementia due to AD were calculated and compared to neuropsychological tests and ApoE genotyping.
Results: Of 17 MCI patients who were amyloid-positive at baseline converted 9 to dementia all of the AD type. 3 of the
11 amyloid-negative MCI subjects converted to dementia but none to dementia due to AD. PPV, NPV and accuracy (to
dementia: 0.53, 0.73 and 0.61; to AD: 0.53, 1.00 and 0.70) was comparable to neuropsychological tests and superior to
Conclusion: All MCI subjects who converted to dementia due to AD were amyloid-positive. However, only 50% of these
MCI due to AD, intermediate likelihood, patients developed manifest dementia due to AD after 24 months limiting the
usefulness of [11C]PiB PET for individual prediction of clinical outcome.
Keywords: Mild cognitive impairment, positron emission tomography, pittsburgh compound b, prospective study, conversion.
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