TY - JOUR T1 - Cortical Aß+/Aß- Parkinson’s disease dementia - two faces of the same coin? JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1642 LP - 1642 VL - 59 IS - supplement 1 AU - Gayane Aghakhanyan AU - Giovanni Palermo AU - Sara Mazzarri AU - Marta Gennaro AU - Federica Guidoccio AU - Daniela Frosini AU - Francesca Betti AU - Luca Antonacci AU - Roberto Ceravolo AU - Duccio Volterrani Y1 - 2018/05/01 UR - http://jnm.snmjournals.org/content/59/supplement_1/1642.abstract N2 - 1642Objectives: To determine whole-brain voxel-wise beta-amyloid (Aß) distribution pattern in cortical Aß PET positive and negative Parkinson’s disease dementia (PDD) patients compared to age matched healthy controls (HCs). Methods: Twenty PDD patients (mean age 71.8 ± 4.6; Mini-Mental State Examination, MMSE 19 ± 4) and six cognitively and clinically normal control subjects (mean age 72 ± 1.6; MMSE 28.8 ± 1.2) were recruited. All demographic and PDD-related clinical data, including the age of PD onset, PD duration, dementia onset and dementia duration were collected. All subjects underwent a 20-min [18F]-Florbetapir PET/CT study, acquired 50 min after intravenous injection of 370 MBq [18F]-Florbetapir. PET images were spatially normalized using the AV45 PET template in MNI brain atlas space (Avid Radiopharmaceuticals) and voxel-wise standardized uptake value ratio (SUVr) images were calculated using the whole cerebellum as a reference region. Qualitative and semi-quantitative reading were carried out for each individual PET study. The threshold to determine Aß positivity scan was arbitrary set at mean cortical SUVR > 1.2. Whole brain voxel-wise analysis of covariance were applied accounting age as a nuisance covariate comparing Aß burden between PDD positive (Aß+), PDD negative (Aß-) and HC groups. Results: Seven out of twenty PDD patients (35%) demonstrated a positive Aß scan according to qualitative reading. Three more patients were categorized as Aß PET positive according to semi-quantitative measurements (50%). Two scans were excluded for further voxel-wise analysis due to motion artifacts. No significant differences in demographic and PDD-related clinical variables were found between Aß+ and Aß- groups. Voxel-wise analysis revealed significant increased cortical Aß binding in the precuneus, right fronto-orbital cortex and in the bilateral putamen (p < 0.001, uncorrected, k = 200 voxels) in PDD Aß+ group compared to HCs. No differences in [18F]-Florbetapir binding were found between PDD Aß- and HC groups. Comparing PDD Aß+ to Aß- group we found increased Aß binding (p < 0.001, uncorrected, k = 200 voxels) in the widespread brain regions, including the frontal pole, cingulate (anterior and posterior division) and paracingulate gyri, precunal cortex, temporal and lateral occipital cortices.Conclusions: The Aß PET was able to separate a distinct category of PDD patients with a pathological cortical retention of amyloid tracer, in a proportion of about 30% similarly to previously published series. However, in addition to visual inspection, the quantitative reading may improve the diagnostic accuracy of inconclusive scans and may affirm the higher incidence of Aß-related pathology in PDD. We demonstrate that selective brain regions might be prone to Aß accumulation in PDD including the precuneus, bilateral putamen and fronto-orbital cortex, nevertheless, these regions do not reflect the full spectrum of AD pathology. Further studies are warranted to unveil the relevance of regional-specific Aß depositions to the cognitive decline in PDD. ER -