Color-coded diffusion-tensor-imaging of posterior cingulate fiber tracts in mild cognitive impairment.
Different processes like microvascular dysfunction, free radical toxicity, beta-amyloid deposits, and Wallerian degeneration can cause functionally relevant disturbances of cerebral neuronal networks by myelin degeneration. Color-coded diffusion-tensor-imaging (ccDTI) allows the structural identification and quantification of myelinated fiber tracts. Particularly, posterior cingulate fiber tracts, which are regarded as important neuronal substrates of the network representing memory processing can be localized only imprecisely by conventional magnetic resonance imaging techniques. The posterior cingulate bundles were assessed by ccDTI in 17 patients with amnestic mild cognitive impairment (MCI), 25 patients with Alzheimer's dementia (DAT), and 21 age-matched controls. Additionally, DTI values were correlated with memory performance in the delayed verbal recall test. Fractional anisotropy and mean diffusivity differed significantly between MCI and controls, as well as between DAT and controls. Performance in the delayed verbal recall test of the entire study group correlated significantly with posterior cingulate bundle anisotropy and diffusivity. Using ccDTI seems, hence, a favorable strategy to detect and quantify the structural integrity of posterior cingulate white matter in MCI. Alterations of DTI parameters substantiate the involvement of white matter pathology in the development of MCI. Moreover, ccDTI could serve as in vivo method to investigate age and disease-related myelin alterations as potential morphological substrates of cognitive dysfunction.
Fellgiebel
Andreas
A
Department of Psychiatry, University of Mainz, Germany. fellgiebel@psychiatrie.klinik.uni-mainz.de
Müller
Matthias J
MJ
Wille
Paulo
P
Dellani
Paulo R
PR
Scheurich
Armin
A
Schmidt
Lutz G
LG
Stoeter
Peter
P
D000368:Aged; D000544:Alzheimer Disease / Q000473:pathology* / Q000503:physiopathology; D016880:Anisotropy; D003072:Cognition Disorders / Q000473:pathology* / Q000503:physiopathology; D038524:Diffusion Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006179:Gyrus Cinguli / Q000473:pathology* / Q000503:physiopathology; D006624:Hippocampus / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D008297:Male; D008569:Memory Disorders / Q000473:pathology / Q000503:physiopathology / Q000523:psychology; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D009434:Neural Pathways / Q000473:pathology* / Q000503:physiopathology; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests