Obejective: To investigate the imaging,pathological,hematocytic, and immunological changes pre- and post swine splenic arterial embolization, using a coaxial microcatheter technique under a balloon catheter occluded the trunck of the splenic artery. To evaluate the potential utility of the new method for management of megalosplenia-hypersplenism.Methods: Seven swines were divided into the experiment and control group.Two swines as the control were treated with the routine method, using the PVA particle and gelfoams for the transcatheter embolization of the splenic artery. Five swines as the experimental group were treated with a new method, using a coaxial microcatheter technique under a balloon catheter occluded the trunck of the splenic artery. An emulsion of N-butyl 2-cyanoacrylate and iodized oil was used for the selective embolization of the splenic artery in the experiment group. The general reaction of the animals, the imaging,pathological, hematological,and immunological changes were observed.Statistics. Measurement data were espressed as means±SD and analyzed by t Test with a STATA7.0 software.Results: (1)In the experiment group ,the first pig showed the symptoms ofvomiting, anorexia and fantod, but these symptoms disappeared in the folbwing day. The third one showed the same symptomsa as the first one but more severely, and died of necrotizing pancreatitis confirmed by pathology in the second dayafter the procedure. The other three appeared normal in the general condition after the treatment. In the control,two swines showed anorexia ,fantod , weak breath for 2 days after the procedure.(2)In the experiment group, selective splenic arterial angiography showed that the contrast medium was slowed dowm in the splenic artery obviously and stagnated in the spleen, and CT plain scan showed decreased in the size of the spleen after 30 minutes under the balloon occlusion of the splenic artery(35~38°/o, p0.05).c) Immunologic changes. There were no significant differences on the immunological test (IgG> IgM> IgA)in the living pigs pre and post the embolization (P>0.05).Conclusions:a) Transcatheter selective splenic arterial embolization using an emulsion of N-butyl 2-cyanoacrylate and iodized oil, under a balloon catheter occluded the trunck of the splenic artery, is an effective new method for treatment of megalosplenia and hypersplenism.b) In comparison with the conventional transcatheter splenic arterial embolization technique, the new method had a less reaction after the embolization.c) Using the new method, recanalization and establishment of collateral branchescould be prevented after embolization of the spleen.