A Larroza1, D Moratal2, V D'ocón Alcañiz1, E Arana3. 1. Centro de Biomateriales e Ingeniería Tisular, Universitat Politècnica de València, Valencia, España. 2. Centro de Biomateriales e Ingeniería Tisular, Universitat Politècnica de València, Valencia, España. Electronic address: dmoratal@eln.upv.es. 3. Servicio de Radiología, Fundación Instituto Valenciano de Oncología, Valencia, España.
Abstract
INTRODUCTION: Brain tractography is a non-invasive medical imaging technique which enables in vivo visualisation and various types of quantitative studies of white matter fibre tracts connecting different parts of the brain. We completed a quantitative study using brain tractography with diffusion tensor imaging in patients with mild cognitive impairment, patients with Alzheimer disease, and normal controls, in order to analyse the reproducibility and validity of the results. SUBJECTS AND METHODS: Fractional anisotropy (FA) and mean diffusivity (MD) were measured across the uncinate fasciculus and the posterior cingulate fasciculus in images, obtained from a database and a research centre, representing 52 subjects distributed among the 3 study groups. Two observers took the measurements twice in order to evaluate intra- and inter-observer reproducibility. RESULTS: Measurements of FA and MD of the uncinate fasciculus delivered an intraclass correlation coefficient above 0.9; ICC was above 0.68 for the posterior cingulate fasciculus. Patients with Alzheimer disease showed lower values of FA and higher MD values in the right uncinate fasciculus in images from the research centre. A comparison of the measurements from the 2 centres revealed significant differences. CONCLUSION: We established a reproducible methodology for performing tractography of the tracts in question. FA and MD indexes may serve as early indicators of Alzheimer disease. The type of equipment and the method used to acquire images must be considered because they may alter results as shown by comparing the 2 data sets in this study.
INTRODUCTION: Brain tractography is a non-invasive medical imaging technique which enables in vivo visualisation and various types of quantitative studies of white matter fibre tracts connecting different parts of the brain. We completed a quantitative study using brain tractography with diffusion tensor imaging in patients with mild cognitive impairment, patients with Alzheimer disease, and normal controls, in order to analyse the reproducibility and validity of the results. SUBJECTS AND METHODS: Fractional anisotropy (FA) and mean diffusivity (MD) were measured across the uncinate fasciculus and the posterior cingulate fasciculus in images, obtained from a database and a research centre, representing 52 subjects distributed among the 3 study groups. Two observers took the measurements twice in order to evaluate intra- and inter-observer reproducibility. RESULTS: Measurements of FA and MD of the uncinate fasciculus delivered an intraclass correlation coefficient above 0.9; ICC was above 0.68 for the posterior cingulate fasciculus. Patients with Alzheimer disease showed lower values of FA and higher MD values in the right uncinate fasciculus in images from the research centre. A comparison of the measurements from the 2 centres revealed significant differences. CONCLUSION: We established a reproducible methodology for performing tractography of the tracts in question. FA and MD indexes may serve as early indicators of Alzheimer disease. The type of equipment and the method used to acquire images must be considered because they may alter results as shown by comparing the 2 data sets in this study.
Authors: Laura E Korthauer; Nicole T Nowak; Scott D Moffat; Yang An; Laura M Rowland; Peter B Barker; Susan M Resnick; Ira Driscoll Journal: Neurobiol Aging Date: 2015-12-17 Impact factor: 4.673
Authors: D Felsky; P Szeszko; L Yu; W G Honer; P L De Jager; J A Schneider; A K Malhotra; T Lencz; T Ikuta; J Pipitone; M M Chakravarty; N J Lobaugh; B H Mulsant; B G Pollock; J L Kennedy; D A Bennett; A N Voineskos Journal: Mol Psychiatry Date: 2013-10-29 Impact factor: 15.992