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O4‐06‐05: Diffusion tensor imaging characteristics of dementia with Lewy bodies and Alzheimer's disease
Author(s) -
Kantarci Kejal,
Avula Ramesh T.,
Senjem Matthew L.,
Samikoglu Ali R.,
Shiung Maria M.,
Przybelski Scott A.,
Weigand Stephen D.,
Ward Heidi A.,
Vemuri Prashanthi,
Ferman Tanis J.,
Boeve Bradley F.,
Knopman David S.,
Petersen Ronald C.,
Jack Clifford R.
Publication year - 2009
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.2009.05.562
Subject(s) - dementia with lewy bodies , diffusion mri , fractional anisotropy , dementia , effective diffusion coefficient , alzheimer's disease , voxel , medicine , nuclear medicine , psychology , neuroscience , pathology , magnetic resonance imaging , radiology , disease
Background: Diffusion tensor MR imaging (DTI) provides information on the integrity of tissue microstructure. The magnitude of diffusivity measured with the apparent diffusion coefficient (ADC) increases, and the directionality of diffusivity measured with fractional anisotropy (FA) decreases with neurodegeneration. The two most common neurodegenerative disorders associated with dementia are Alzheimer’s disease (AD) and dementia with Lewy bodies (DLB). Little is known about the DTI changes in DLB. Our objective was to determine the regional DTI characteristics of patients with DLB compared to patients with AD and cognitively normal subjects (CN). Methods: We studied clinically diagnosed age, gender and education matched patients with DLB (n 1⁄4 24), AD (n 1⁄4 24), and CN (n 1⁄4 24). DLB and AD subjects were further matched on dementia severity based on Clinical Dementia Rating scores. Parallel imaging was performed at 3 T using an acceleration factor of two. 3DMPRAGE was performed for anatomical segmentation and labeling. In order to avoid partial volume averaging of tissue diffusivity with CSF, we used an EPI-FLAIR-DTI sequence (which nulls CSF) with 21 diffusion sensitive gradient directions (b 1⁄4 1000 s/mm). We measured ADC from segmented cortical gray matter in regions derived from the automated anatomic labeling atlas. Color FA maps were used for measuring tract-based FA and ADC. Voxel-based analysis was performed to determine gray matter ADC differences among the clinical groups. Results: In the cortical gray matter, patients with DLB and AD had elevated ADC in the amygdala compared to CN subjects (p 1⁄4 0.01). In addition, patients with AD had elevated ADC in the hippocampus and other temporal lobe regions, compared to DLB and CN subjects (p < 0.01). The posterior cingulum white matter tract ADC was elevated (p < 0.01) and FA was decreased (p < 0.05) in patients with AD compared to DLB and CN subjects. SPM5 analysis showed additional ADC elevation in the head of caudate nucleus and putamen in patients with DLB. Conclusions: DLB is characterized by elevated ADC in the amygdala, consistent with the neurodegenerative pathological involvement during the limbic-transitional stage of Lewy body disease. DTI findings agree with the expected pattern of neurodegenerative pathological involvement in clinically diagnosed patients with DLB and AD, and may be useful in differential diagnosis and disease characterization.