%0 Journal Article %J J Alzheimers Dis %D 2022 %T Medial Temporal Atrophy in Posterior Cortical Atrophy and Its Relationship to the Cingulate Island Sign. %A Josephs, Kennedy A %A Pham, Nha Trang Thu %A Graff-Radford, Jonathan %A Machulda, Mary M %A Lowe, Val J %A Whitwell, Jennifer L %K Alzheimer Disease %K Atrophy %K Fluorodeoxyglucose F18 %K Humans %K Lewy Body Disease %K Magnetic Resonance Imaging %K Positron-Emission Tomography %X

BACKGROUND: It has been hypothesized that medial temporal sparing may be related to preserved posterior cingulate metabolism and the cingulate island sign (CIS) on [18F]fluorodeoxyglucose (FDG) PET in posterior cortical atrophy (PCA).

OBJECTIVE: To assess the severity of medial temporal atrophy in PCA and determine whether the presence of a CIS is related to medial temporal sparing.

METHODS: Fifty-five PCA patients underwent MRI and FDG-PET. The degree and symmetry of medial temporal atrophy on MRI was visually assessed using a five-point scale for both hemispheres. Visual assessments of FDG-PET coded the presence/absence of a CIS and whether the CIS was symmetric or asymmetric. Hippocampal volumes and a quantitative CIS were also measured.

RESULTS: Medial temporal atrophy was most commonly mild or moderate, was symmetric in 55% of patients, and when asymmetric was most commonly worse on the right (76%). Older age and worse memory performance were associated with greater medial temporal atrophy. The CIS was observed in 44% of the PCA patients and was asymmetric in 50% of these. The patients with a CIS showed greater medial temporal asymmetry, but did not show lower medial temporal atrophy scores, compared to those without a CIS. Hippocampal volumes were not associated with quantitative CIS.

CONCLUSION: Mild medial temporal atrophy is a common finding in PCA and is associated with memory impairment. However, medial temporal sparing was not related to the presence of a CIS in PCA.

%B J Alzheimers Dis %V 86 %P 491-498 %8 2022 %G eng %N 1 %1 https://www.ncbi.nlm.nih.gov/pubmed/35068459?dopt=Abstract %R 10.3233/JAD-215263 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Characterizing White Matter Tract Degeneration in Syndromic Variants of Alzheimer's Disease: A Diffusion Tensor Imaging Study. %A Madhavan, Ajay %A Schwarz, Christopher G %A Duffy, Joseph R %A Strand, Edythe A %A Machulda, Mary M %A Drubach, Daniel A %A Kantarci, Kejal %A Przybelski, Scott A %A Reid, Robert I %A Senjem, Matthew L %A Gunter, Jeffrey L %A Apostolova, Liana G %A Lowe, Val J %A Petersen, Ronald C %A Jack, Clifford R %A Josephs, Keith A %A Whitwell, Jennifer L %K Aged %K Alzheimer Disease %K Aniline Compounds %K Anisotropy %K Aphasia, Primary Progressive %K Case-Control Studies %K Diffusion Tensor Imaging %K Female %K Humans %K Image Processing, Computer-Assisted %K Male %K Middle Aged %K Nerve Fibers, Myelinated %K Neurodegenerative Diseases %K Neuropsychological Tests %K Positron-Emission Tomography %K Psychiatric Status Rating Scales %K Retrospective Studies %K Thiazoles %K White Matter %X

BACKGROUND: Different clinical syndromes can arise from Alzheimer's disease (AD) neuropathology, including dementia of the Alzheimer's type (DAT), logopenic primary progressive aphasia (lvPPA), and posterior cortical atrophy (PCA).

OBJECTIVE: To assess similarities and differences in patterns of white matter tract degeneration across these syndromic variants of AD.

METHODS: Sixty-four subjects (22 DAT, 24 lvPPA, and 18 PCA) that had diffusion tensor imaging and showed amyloid-β deposition on PET were assessed in this case-control study. A whole-brain voxel-based analysis was performed to assess differences in fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity across groups.

RESULTS: All three groups showed overlapping diffusion abnormalities in a network of tracts, including fornix, corpus callosum, posterior thalamic radiations, superior longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, and uncinate fasciculus. Subtle regional differences were also observed across groups, with DAT particularly associated with degeneration of fornix and cingulum, lvPPA with left inferior fronto-occipital fasciculus and uncinate fasciculus, and PCA with posterior thalamic radiations, superior longitudinal fasciculus, posterior cingulate, and splenium of the corpus callosum.

CONCLUSION: These findings show that while each AD phenotype is associated with degeneration of a specific structural network of white matter tracts, striking spatial overlap exists among the three network patterns that may be related to AD pathology.

%B J Alzheimers Dis %V 49 %P 633-43 %8 2016 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/26484918?dopt=Abstract %R 10.3233/JAD-150502