title: Diffusion effects on longitudinal relaxation in poorly mixed compartments.
abstract: Diffusion of spins between physical or virtual, communicating compartments having different states of longitudinal magnetization leads to diffusion-driven longitudinal relaxation. Herein, in two model systems, the effects of diffusion-driven longitudinal relaxation are explored experimentally and analyzed quantitatively. In the first case, longitudinal relaxation in a single slice of a water phantom is monitored spectroscopically as a function of slice thickness. In the second case, mimicking vascular flow/diffusion effects, longitudinal relaxation is monitored in a two-compartment, semi-permeable fiber phantom. In both cases, apparent longitudinal relaxation, though clearly multi-exponential, is well-modeled as bi-exponential.
authors.affiliation: Department of Chemistry, Washington University, St. Louis, MO 63130, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Anderson
authors.forename: Q
authors.initials: Q
authors.lastname: Ye
authors.forename: J J
authors.initials: JJ
authors.lastname: Neil
authors.forename: J J H
authors.initials: JJ
authors.lastname: Ackerman
authors.forename: J R
authors.initials: JR
authors.lastname: Garbow
mesh_terms: D000465:Algorithms; D001499:Bayes Theorem; D003287:Contrast Media; D004058:Diffusion; D004574:Electromagnetic Fields; D019786:Gadolinium DTPA / Q000737:chemistry; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D015233:Models, Statistical; D010539:Permeability; D019047:Phantoms, Imaging
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA