¹H spin–lattice relaxation in water solution of ²⁰⁹Bi counterparts of Gd³⁺contrast agents

Abstract

1 H spin-lattice relaxation studies of water solutions of Bismuth-ethylenediamine-tetraacetic acid (Bi-EDTA), Bismuth-ethylenediamine-tetrakis(methylenephosphonic) acid (Bi-EDTP), Bismuth-1,4,7,10tetraazacyclododecane-1,4,7,10-tetraacetic acid (Bi-DOTA), Bismuth-1,4,7,10-tetraazacyclodo decane-1,4,7,10-tetrakis(methylenephosphonic acid) (Bi-DOTP) and Bismuth-1,4,7,10-tetraazacyclo dodecane-1,4,7-triacetic acid (Bi-DO3A) have been performed in order to compare Quadrupole Relaxation Enhancement (QRE) effects with Paramagnetic Relaxation Enhancement (PRE) from the perspective of exploiting the first one as a novel contrast mechanism for Magnetic Resonance Imaging (MRI). The selected compounds can be considered as 209 Bi counterparts of Gd 3+ complexes. The relaxation experiments have been performed in a broad frequency range of 5 kHz-30 MHz. The relaxation contribution associated with QRE has been extracted from the data and compared with PRE. Similarities and differences between the two effects have been discussed.

Mechanism of Water Dynamics in Hyaluronic Dermal Fillers Revealed by Nuclear Magnetic Resonance Relaxometry

“…Moreover, the normalized relaxation rates for DF1, DF2 and DF3 follow at low frequencies a linear dependence on ln w over two frequency decades; such a dependence is a marker of 2D translation diffusion. 1 H water relaxation rates in confinement are proportional (after subtracting the contribution to the overall relaxation from bulk water) to the fraction of bound water molecules, providing the exchange lifetime, t ex , between the confined and bulk water pools is sufficiently short, so it can be omitted in the dominator of Equation (7): [38,39] The 2D diffusion suggests that the chains form locally flat surfaces.…”