Sirong Chen, Presenter: Nothing to Disclose

Yim Lung Leung, Abstract Co-Author: Nothing to Disclose

Thomas KC Cheng MBBS, Abstract Co-Author: Nothing to Disclose

Ka Nin Wong, Abstract Co-Author: Nothing to Disclose

William Cheung, Abstract Co-Author: Nothing to Disclose

Man Ki Cheung, Abstract Co-Author: Nothing to Disclose

Vincent Mok, Abstract Co-Author: Nothing to Disclose

Chi Lai Ho, Abstract Co-Author: Nothing to Disclose

Concurrent Alzheimer’s Disease (AD) pathology is common in post stroke dementia (PSD). Clinical assessment or structural imaging for differentiation is difficult as typical AD features may co-exist with post-stroke changes in vascular dementia (VD). We aim to use 11C-PIB PET for evaluation of concurrent AD in PSD by detection of PIB binding in brain areas known to accumulate high β-amyloid (Ab) plaques in early AD.

39 PSD patients (M: 21, F: 18; age range: 58-89y, mean=77±6.7y) were referred from the Neurology clinic. 39 age & sex matched early AD (age range: 51-87y, mean=76±10.9y) and 39 normal subjects (age range: 49-88y, mean=72±9.1y) were recruited as control. All patients underwent PET/CT at 5 & 35 min after 11C-PIB injection (~15mCi). The target regions: frontal gyrus, gyrus rectus, superior parietal lobe, posterior cingulate, precuneus, lateral temporal lobe, occipital lobe, caudate, putamen, were drawn automatically on 2 sets of PET. Global PIB binding (GPB) composing of the above regions normalized to cerebellum was calculated. ROC analysis was performed between AD and normal patients for defining the GPB cut-off for AD. PSD patient with visually increased PIB uptake at posterior cingulate, precuneus, frontal, parietal and/or lateral temporal cortex, supported by GPB>=cut-off was considered as having concurrent AD.

The GPB cut-off for AD was 1.42. Visual assessment supported by GPB>=1.42 identified 14/39 (35.9%) PSD patients having concurrent AD. Compared with the AD control, PSD patients with concurrent AD showed great similarity in GPB (1.73±0.14 vs 1.71±0.12, P>>0.05) and PIB distribution, both having significantly higher GPB than normal control (1.28±0.09, both P<<0.05). On the contrary, pure VD patients (25/39) showed great similarity to normal subjects (GPB=1.29±0.07 vs 1.28±0.09, P>>0.05) but significantly lower GPB than AD control (P<<0.05). Concurrent AD showed significantly higher GPB than pure VD in PSD patients (1.71±0.12 vs 1.29±0.07, P<<0.05).

11C-PIB PET is valuable for evaluation of concurrent AD pathology in PSD in vivo. Concurrent AD is common in PSD, which may warrant specific treatments targeting Ab plaques in these patients.

11C-PIB PET is valuable for evaluation of concurrent AD pathology in PSD in vivo. Apart from prevention of recurrent stroke, treatments targeting Ab plaques might benefit this group of PSD patients.

Chen, S, Leung, Y, Cheng, T, Wong, K, Cheung, W, Cheung, M, Mok, V, Ho, C, 11C-PIB PET for Evaluation of Concurrent Alzheimer’s Disease in Post Stroke Dementia.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14006374.html