[Porous gelatin particles for hepatic arterial embolization; investigation of the size distribution and fragmentation before and after microcatheter passage].

Liver abscess formation has been recently concerned after hepatic arterial embolization using porous gelatin particles( Gelpart)(GP), and inhomogeneous particles size or fragmentation of GP may partly contribute to this complication. The purpose of this study was to investigate the size distribution and incidence of fragments of GP before and after microcatheter passage. 1 mm- and 2 mm-GP were injected into three microcatheters with different inner-diameters by three interventional radiologists. The particles were stained with methylene blue dye, and the longer- and shorter-particle diameters were measured by a digital microscope. The particles less than 300 microm and 600 microm in longer- diameter was defined as fragment for 1 mm- and 2 mm-GP, respectively. Diameter of GP showed a wide bimodal distribution by fragments and non-fragment particles. The change of mean particle diameter ranged within 10%, and the ratio of shorter- to longer-particle diameter remained similarly at 0.75. The incidence of fragments was approximately 10% and 5% before microcatheter passage and increased by one-two times and two-five times after microcatheter passage for 1 mm- and 2 mm-GP, respectively. In conclusion, GP were ununiform in particle size distribution and contained fragments. GP did not change in shape significantly after microcatheter passage, however, 2 mm-GP was more prone to fragmentation than 1 mm-GP.