title: Characterization of white matter fiber bundles with T2* relaxometry and diffusion tensor imaging.
abstract: In this study, diffusion tensor imaging (DTI) and T(2)* multiechorelaxometry were combined in 30 healthy subjects at 3T, with the aim of characterizing the spatial distribution of relaxation rates in white matter (WM). Region of interest (ROI) analysis was performed in 23 different fiber tracts automatically defined in standard space. Spearman rank analysis was performed on regional values of T(2)*, fractional anisotropy (FA), and radial diffusivity (RD). A strong relationship was observed between the location and direction of fiber bundles and relaxation rates, and adjacent fiber bundles with similar orientation showed very different relaxation rates. Moreover, while relaxation rates varied largely between different fiber tracts, variation of the same parameter within the same anatomical fiber bundle across individuals was remarkably limited. The rich variability of relaxation rates in WM and their complex relationship with DTI data suggested that the two techniques might be sensitive to complementary characteristics of myelin structure. This has tremendous potential to allow for a more detailed understanding of brain development and pathology, in particular in the context of age-related cognitive decline.
authors.affiliation: Department of Clinical and Behavioral Neurology, Santa Lucia Foundation, Rome, Italy. a.cherubini@hsantalucia.it
authors.forename: Andrea
authors.initials: A
authors.lastname: Cherubini
authors.forename: Patrice
authors.initials: P
authors.lastname: Péran
authors.forename: Gisela Elisabeth
authors.initials: GE
authors.lastname: Hagberg
authors.forename: Ambra Erika
authors.initials: AE
authors.lastname: Varsi
authors.forename: Giacomo
authors.initials: G
authors.lastname: Luccichenti
authors.forename: Carlo
authors.initials: C
authors.lastname: Caltagirone
authors.forename: Umberto
authors.initials: U
authors.lastname: Sabatini
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Spalletta
mesh_terms: D000328:Adult; D000465:Algorithms; D001185:Artificial Intelligence; D001921:Brain / Q000033:anatomy & histology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity