摘要篇首： Onyx, a novel embolization material, is a mixture of ethylene-vinyl alcohol copolymer (EVOH), dimethyl sulfoxide (DMSO), and micronized tantalum. The polymer is dissolved in DMSO and is prepared in different concentration. Onyx HD-500 for aneurysm embolization contains 20% copolymer and 80% DMSO. Onyx-18 for arteriovenous malformations (AVMs) embolization contains 6.0% copolymer and 94.0% DMSO. When Onyx comes in contact with water or blood, the copolymer precipitates because of rapid diffusion of the DMSO solvent. It possesses stronger cohesiveness, but less likely to entrap the microcatheter. From September 2003, we have used Onyx to treat large and giant cerebral aneurysms and AVMs successfully in 10 patients. Here we report our preliminary experience with the Onyx technique.