title: Detection of microscopic anisotropy in gray matter and in a novel tissue phantom using double Pulsed Gradient Spin Echo MR.
abstract: A double Pulsed Gradient Spin Echo (d-PGSE) MR experiment was used to measure and assess the degree of local diffusion anisotropy in brain gray matter, and in a novel "gray matter" phantom that consists of randomly oriented tubes filled with water. In both samples, isotropic diffusion was observed at a macroscopic scale while anisotropic diffusion was observed at a microscopic scale, however, the nature of the resulting echo attenuation profiles were qualitatively different. Gray matter, which contains multiple cell types and fibers, exhibits a more complicated echo attenuation profile than the phantom. Since microscopic anisotropy was observed in both samples in the low q regime comparable to that achievable in clinical scanner, it may offer a new potential contrast mechanism for characterizing gray matter microstructure in medical and biological applications.
authors.affiliation: Section on Tissue Biophysics and Biomimetics, NICHD, NIH, Bethesda, MD 20892, USA. michalk@mail.nih.gov
authors.forename: M E
authors.initials: ME
authors.lastname: Komlosh
authors.forename: F
authors.initials: F
authors.lastname: Horkay
authors.forename: R Z
authors.initials: RZ
authors.lastname: Freidlin
authors.forename: U
authors.initials: U
authors.lastname: Nevo
authors.forename: Y
authors.initials: Y
authors.lastname: Assaf
authors.forename: P J
authors.initials: PJ
authors.lastname: Basser
mesh_terms: D000465:Algorithms; D000818:Animals; D016880:Anisotropy; D001921:Brain / Q000378:metabolism* / Q000473:pathology*; D002490:Central Nervous System; D003198:Computer Simulation; D017352:Echo-Planar Imaging; D008253:Macaca mulatta; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D019047:Phantoms, Imaging