ANALYSIS OF DISCRETE T-2 COMPONENTS OF NMR RELAXATION FOR AQUEOUS-SOLUTIONS IN HOLLOW-FIBER CAPILLARIES

An analysis is presented of proton NMR T-2 relaxation times measured f or aqueous solutions in simple bundles of hollow fibers. The relaxatio n times are calculated with a two-compartment diffusive exchange model using the known relaxation times of the aqueous solutions and the fib er geometry. When the relaxation time outside the fibers is short (sim ilar to 1 ms), three or more relaxation components are observed from t his two compartment system, in agreement with the calculation. The amp litude and relaxation times of the third component are consistent with those of a diffusion-mediated mode, as suggested theoretically by Bro wnstein and Tarr (Phys. Rev. A 19, 2446 (1979)). The possible contribu tion of such modes to the multicomponent relaxation observed in tissue s is discussed.