title: Examining the gateway to the limbic system with diffusion tensor imaging: the perforant pathway in dementia.
abstract: Current treatments for Alzheimer's disease (AD) are only able to slow the progression of mental deterioration, making early and reliable diagnosis an essential part of any promising therapeutic strategy. In the initial stages of AD, the first neuropathological alterations occur in the perforant pathway (PP), a large neuronal fiber tract located at the entrance to the limbic system. However, to date, there is no sensitive diagnostic tool for performing in vivo assessments of this structure. In the present bimodal magnetic resonance imaging (MRI) study, we examined 10 elderly controls, 10 subjects suffering from mild cognitive impairment (MCI), and 10 AD patients in order to evaluate the sensitivity of diffusion tensor imaging (DTI), a new MRI technique, for detecting changes in the PP. Furthermore, the diagnostic explanatory power of DTI data of the PP should be compared to high-resolution MRI volumetry and intervoxel coherences (COH) of the hippocampus and the entorhinal cortex, two limbic regions also involved in the pathophysiology of early AD. DTI revealed a marked decrease in COH values in the PP region of MCI (right side: 26%, left side: 29%, as compared to controls) and AD patients (right side: 37%, left side: 43%, as compared to controls). Reductions in COH values of the PP region were significantly correlated with cognitive impairment. DTI data of the PP zone were the only parameter differing significantly between control subjects and MCI patients, while the volumetric measures and the COH values of the hippocampus and the entorhinal cortex did not. DTI of medial temporal brain regions is a promising non-invasive tool for the in vivo diagnosis of the early/preclinical stages of AD.
authors.affiliation: Department of Psychiatry, Charité University Medicine, Campus Mitte, Berlin, Germany. peter.kalus@charite.de
authors.forename: Peter
authors.initials: P
authors.lastname: Kalus
authors.forename: Johannes
authors.initials: J
authors.lastname: Slotboom
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gallinat
authors.forename: Richard
authors.initials: R
authors.lastname: Mahlberg
authors.forename: Katja
authors.initials: K
authors.lastname: Cattapan-Ludewig
authors.forename: Roland
authors.initials: R
authors.lastname: Wiest
authors.forename: Thomas
authors.initials: T
authors.lastname: Nyffeler
authors.forename: Caroline
authors.initials: C
authors.lastname: Buri
authors.forename: Andrea
authors.initials: A
authors.lastname: Federspiel
authors.forename: Dieter
authors.initials: D
authors.lastname: Kunz
authors.forename: Gerhard
authors.initials: G
authors.lastname: Schroth
authors.forename: Claus
authors.initials: C
authors.lastname: Kiefer
mesh_terms: D000368:Aged; D003072:Cognition Disorders / Q000175:diagnosis* / Q000503:physiopathology*; D003704:Dementia / Q000175:diagnosis* / Q000503:physiopathology*; D038524:Diffusion Magnetic Resonance Imaging; D018728:Entorhinal Cortex / Q000503:physiopathology*; D005260:Female; D006624:Hippocampus / Q000503:physiopathology*; D006801:Humans; D008032:Limbic System / Q000503:physiopathology*; D008297:Male; D019580:Perforant Pathway / Q000503:physiopathology*