title: Diffusion tensor imaging in Alzheimer's disease and affective disorders.
abstract: The functional organization of the brain in segregated neuronal networks has become a leading paradigm in the study of brain diseases. Diffusion tensor imaging (DTI) allows testing the validity and clinical utility of this paradigm on the structural connectivity level. DTI in Alzheimer's disease (AD) suggests a selective impairment of intracortical projecting fiber tracts underlying the functional disorganization of neuronal networks supporting memory and other cognitive functions. These findings have already been tested for their utility as clinical markers of AD in large multicenter studies. Affective disorders, including major depressive disorder (MDD) and bipolar disorder (BP), show a high comorbidity with AD in geriatric populations and may even have a pathogenetic overlap with AD. DTI studies in MDD and BP are still limited to small-scale monocenter studies, revealing subtle abnormalities in cortico-subcortial networks associated with affect regulation and reward/aversion control. The clinical utility of these findings remains to be further explored. The present paper presents the methodological background of diffusion imaging, including DTI and diffusion spectrum imaging, and discusses key findings in AD and affective disorders. The results of our review strongly point toward the necessity of large-scale multicenter multimodal transnosological networks to study the structural and functional basis of neuronal disconnection underlying different neuropsychiatric diseases.
authors.affiliation: Department of Psychosomatic Medicine, University of Rostock, Gehlsheimer Str. 20, 18147, Rostock, Germany, stefan.teipel@med.uni-rostock.de.
authors.forename: Stefan J
authors.initials: SJ
authors.lastname: Teipel
authors.forename: Martin
authors.initials: M
authors.lastname: Walter
authors.forename: Yuttachai
authors.initials: Y
authors.lastname: Likitjaroen
authors.forename: Peter
authors.initials: P
authors.lastname: Schönknecht
authors.forename: Oliver
authors.initials: O
authors.lastname: Gruber
mesh_terms: D000544:Alzheimer Disease / Q000150:complications / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D019964:Mood Disorders / Q000150:complications / Q000473:pathology*; D009415:Nerve Net / Q000473:pathology; D009434:Neural Pathways / Q000473:pathology