POLYVINYL-ALCOHOL PARTICLE-SIZE AND SUSPENSION CHARACTERISTICS

PURPOSE: To evaluate the size and shape of commercially available poly vinyl alcohol (PVA) particles and to determine whether they change in size when suspended in nonionic contrast and in a solution of nonionic contrast and absolute alcohol. METHODS: The two-dimensional area and the long and short axis of PVA particles from several different vendor s were measured using a light microscope attached to a video system an d an image-processing software program. Particles were measured as pac kaged (dry or suspended in saline), suspended in ioversol, and suspend ed in ioversol containing 30% alcohol, RESULTS: All brands of dry part icles had similar microscopic appearances, The saline-suspended partic les had fewer and finer perforations. After suspension in contrast, al l sizes and brands of dry particles significantly increased in size. T he particles packaged in saline did not expand. The addition of alcoho l to the contrast did not consistently change particle size. Particle aggregation was similar in both contrast suspensions for all groups of particles. Particles less than 50 mu m in size were rarely observed i n any PVA preparation after suspension. CONCLUSIONS: The three dry PVA preparations seen to be similar. An increase significantly in size wh en suspended in nonionic contrast or contrast-alcohol solutions. The s aline-packaged PVA particles were different from the dry variety and d id not enlarge in contrast or contrast-alcohol solutions. Alcohol did not change the size or suspension characteristics of PVA particles. Pa rticles less than 50 mu m in size were rarely identified.