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P2‐094: Correlating imaging with language impairment in degenerative dementias: How well do PIB and FDG PET match behavior?
Author(s) -
Chertkow Howard,
Nikelski James,
Léger Gabriel,
Probst Stephan,
Pilon Randi,
Solomon Shelley,
Whitehead Victor
Publication year - 2011
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2011.05.984
Subject(s) - primary progressive aphasia , pittsburgh compound b , tauopathy , grey matter , positron emission tomography , frontotemporal lobar degeneration , dementia , psychology , atrophy , medicine , pathology , white matter , neuroscience , nuclear medicine , frontotemporal dementia , magnetic resonance imaging , neurodegeneration , radiology , disease
Background: Alzheimer’s Disease (AD) has a typical course characterized by prominent memory impairment while in Primary Progressive Aphasia (PPA) language problems can be the primary or sole deficit. While PPA can be a clinicalmanifestation of frontotemporal dementia pathology (tauopathy or tardopathy), in a particular subgroup, termedLogopenic PrimaryProgressiveAphasia,AD is often the underlyingpathologydespite the “focality” of the cognitive deficit. We wondered whether multi-modal imaging with Flouro-deoxyglucose PET (FDG) andC-11 amyloid PETimagingwith Pittsburgh B Compound (PIB) would demonstrate different lesion localizations between these AD groups in a coherent fashion. We hypothesized that these imaging modalities would be convergent, and usually all point in the direction of AD (bilateral deficits) vs. PPA(strictly left temporal/frontal deficits). Methods: Fourteen subjects with typical AD and 12 with PPA-LV were studied. MRI was assessed visually and with VBM of grey matter. FDGPET scans were assessed as typical AD [ ie., bitemporo-parietal decreased glucose uptake] or left predominant pattern of decreased metabolism, on clinical as well as SUVR analysis. PIB PET amyloid imaging was considered positive if there was SUVR >1.5 for association cortex regions, corresponding to medium or large PIB uptake on visual inspection. Similar patterns of PIB deposition on visual analysis as well as SUVR comparison were assessed. Results: On MRI scan, 12/14 ADs and 6/12 PPA-LVs showed hippocampalatrophy; 4/14 ADs and 6/12 PPA-LVs showed predominantly left sided cortical atrophy. On FDG PET scanning, 5/12 ADs and 10/ 12PPA-LVs showed predominantly left sided hypometabolism. On PIB PET scanning, there was no visual or SUVR difference between left sided PIB uptake between the two sets of individuals. There was no significant left PIB predominance in either group.Conclusions:Among those clinically labeled as PPA-LV, amyloid imaging with PIB showed no particular differences from typical AD individuals amyloid was seen on both sides of the brain. MRI and FDG PET both showed left sided abnormalities more commonly (but not exclusively) in the PPA-LV group compared to typical AD individuals. There was overlap in all modalities between imaging modalities. FDG PET appears most reliably to mirror cognitive deficits, in that the pattern in PPA-LV subjects showed the greatest differences from typical AD subjects. Supported by the CIHR (Canadian Institutes of Health Research), and the FRSQ Quebec Aging Network (RQRV).