View unanswered posts | View active topics It is currently Wed Aug 20, 2014 12:49 pm



Reply to topic  [ 1 post ] 
 MRI patterns differentiate DLB/AD from AD 
Author Message

Joined: Fri Aug 11, 2006 1:46 pm
Posts: 4811
Location: SF Bay Area (Northern CA)
Post MRI patterns differentiate DLB/AD from AD
This research article addresses a question I've had for awhile now: if those with Lewy Body Dementia commonly have concurrent Alzheimer's pathology, how can you differentiate DLB/AD from AD in living people?

According to this article, "increased amygdalar diffusivity in the absence of tissue loss" is specific to DLB. Of course, one of the limitations of this research article is that the clinical diagnoses of DLB and AD have not been confirmed with brain autopsy.

Here's the abstract.

Robin


Neurology. 2010 Jun 1;74(22):1814-21.

Dementia with Lewy bodies and Alzheimer disease: Neurodegenerative patterns characterized by DTI.

Kantarci K, Avula R, Senjem ML, Samikoglu AR, Zhang B, Weigand SD, Przybelski SA, Edmonson HA, Vemuri P, Knopman DS, Ferman TJ, Boeve BF, Petersen RC, Jack CR Jr.
Mayo Clinic, Rochester, MN

Abstract
OBJECTIVE: To identify the patterns of diffusivity changes in patients with dementia with Lewy bodies (DLB) and Alzheimer disease (AD) and to determine whether diffusion tensor MRI (DTI) is complementary to structural MRI in depicting the tissue abnormalities characteristic of DLB and AD.

METHODS: We studied clinically diagnosed age-, gender-, and education-matched subjects with DLB (n = 30), subjects with AD (n = 30), and cognitively normal (CN) subjects (n = 60) in a case-control study. DTI was performed at 3T with a fluid-attenuated inversion recovery-based DTI sequence that enabled cortical diffusion measurements. Mean diffusivity (MD) and gray matter (GM) density were measured from segmented cortical regions. Tract-based diffusivity was measured using color-coded fractional anisotropy (FA) maps.

RESULTS: Patients with DLB were characterized by elevated MD in the amygdala and decreased FA in the inferior longitudinal fasciculus (ILF). ILF diffusivity was associated with the presence of visual hallucinations (p = 0.007), and amygdala diffusivity was associated with Unified Parkinson's Disease Rating Scale (r = 0.50; p = 0.005) in DLB. In contrast, patients with AD were characterized by elevated MD in the medial temporal, temporal, and parietal lobe association cortices and decreased FA in the fornix, cingulum, and ILF. Amygdala diffusivity was complementary to GM density in discriminating DLB from CN; hippocampal and parahippocampal diffusivity was complementary to GM density in discriminating AD from CN.

CONCLUSION: Increased amygdalar diffusivity in the absence of tissue loss in dementia with Lewy bodies (DLB) may be related to microvacuolation, a common pathology associated with Lewy body disease in the amygdala. Diffusivity measurements were complementary to structural MRI, demonstrating that measures of diffusivity on diffusion tensor MRI are valuable tools for characterizing the tissue abnormalities characteristic of Alzheimer disease and DLB.

PubMed ID#: 20513818 (see pubmed.gov for abstract only)


Wed Jun 02, 2010 2:08 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 1 post ] 

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by STSoftware for PTF.
Localized by MaĆ«l Soucaze © 2010 phpBB.fr