In vitro and in vivo comparative performance studies of gadolinium-loaded zeolites and Gd-DOTA as contrast agents for MRI applications.

Gadolinium-based contrast agents (CAs) were synthesized using faujasite zeolite (NaX) and zeolite beta (BEA) and their performances in vitro and in vivo were compared to the widely used commercial CA, gadoteric acid (Gd-DOTA). Magnetic resonance imaging (MRI) relaxometry studies (considering longitudinal [T ] and transverse [T ] relaxation times) were performed using Gd-DOTA and the zeolitic materials loaded with Gd . The Gd-loaded NaX, which presented large pores and cavities (7.

H, Si and Sn double and triple resonance NMR spectroscopy of the small-pore framework sodium stannosilicate NaSnSiO·2HO.

The small-pore framework sodium stannosilicate AV-10, chemical composition NaSnSiO·2HO and known crystallographic structure, was synthesized by hydrothermal crystallization. This stannosilicate is built up of a three-dimensional network of corner-shared SiO tetrahedra and SnO octahedra. The SnO sites are linked to six SiO tetrahedra (Sn(6Si)) while each of the two crystallographically different SiO units are connected to two SnO and SiO units (Si(2Si,2Sn)).