[New porous gelatin particles for hepatic arterial embolization--investigation of passage through current microcatheters].

Hepatic arterial embolization (HAE) has been widely performed for unresectable hepatocellular carcinoma (HCC) in a selective manner using a microcatheter. Gelatin sponge is exclusively used as an embolic agent, though it has not yet been approved for an arterial blockade. Recently, new porous gelatin particles (GP) have been approved and are clinically available. In this study, passage of GP through microcatheters was investigated, as it is an important requirement for a new agent. Both 1-mm and 2-mm GP were injected through each of six current 2.0 Fr-2.7 Fr microcatheters by five board-certified interventional radiologists. In general, use of a 2.5 mL lock syringe was associated with higher subjective resistance score (5-10/10), longer injection time (20-30 sec), and lower injection pressure (1.0-2.5 MPa) with difficulty. When it was impossible to inject GP with a 2.5-mL lock syringe,injection was retested with a 1 mL lock syringe resulting in lower resistance score (1-6), shorter injection time (6-10 sec), and higher injection pressure (1.5-2.5 MPa) regardless of particle size. Thus,it is recommended to use a 1 mL lock syringe for injection of GP through a microcatheter. After passing through a 2.0 Fr microcatheter, 2 mm particles showed no significant deformation or fragmentation under observation by stereomicroscopy.