간동맥 화학색전술에 사용하는 색전물질에 대한 고찰

곽병국 ( Byung Kook Kwak ),심형진 ( Hyung Jin Shim ) 대한간암학회 2011 대한간암학회지 Vol.11 No.1

Four procedures on intraarterial catheter-based therapy are available in treating hepatocellular carcinoma: intraarterial chemotherapy (IAC), transcatheter arterial embolization (TAE), conventional transcatheter arterial chemoembolization (cTACE), and transcatheter arterial chemoembolization using drug-eluting bead (DEB-TACE). On the bases of 2009 Practice Guideline for Diagnosis and Treatment of Hepatocellular Carcinoma by The Korean Liver Cancer Study Group and National Cancer Center, and 2010 AASLD Practice Guideline by American Association for the Study of Liver Disease, substances and recommendations on interventional managements were reviewed. Various kinds of embolic materials used in the procedures of TAE, cTACE and DEB-TACE were described in detail.

Hepatic CT Enhancement: Comparison between Dimeric and Monomeric Nonionic Contrast Agents in Rabbits

김기현,곽병국,심형진,김교남,유위강,유승훈,김양수,이종범,김건상,Kim, Gi-Hyeon,Kwak, Byung-Kook,Shim, Hyung-Jin,Kim, Kyo-Nam,Liu, Wei Chiang,Ryu, Seung-Hoon,Kim, Yang-Soo,Lee, Jong-Beum,Kim, Kun-Sang The Korean Radiological Society 2003 대한영상의학회지 Vol.48 No.6

목적: 정상 가토에서 비이온성 이중체(dimer)인 iodixanol과 단량체(monomer)인 ioversol간의 간과 대동맥에서의 조영증강 정도를 비교하고자 하였다. 대상과 방법: 나선식 CT를 이용하여 가토 7마리에서 일주일 간격을 두고 iodixanol(Visipaque 320, Nycomed, Oslo, Norway)과 ioversol(Optiray 320, Mallincrodt medical, Quebec, Canada)로 각각 3초간격으로 120초 동안 간의 한부위에서 역동적 CT를 시행하였다. 각 가토 체중에 따라 동일량의 조영제를 사용하였으며 2(ml/kg), 조영 증강치와 최고 조영 증강치에 도달하는 평균 시간을 산출한 후 조영증강 곡선을 구하였고, 두 조영제간의 차이를 통계학적으로 비교하였다. 결과: 간실질의 평균 조영 증강치는 후기 동맥기에서 조기 문맥기(18-39초)에 이르는 동안 ivorsol을 사용한 예에서 더 높게 관찰 되었으며 통계학적으로 의의가 있었다(P<0.05). 또한 간실질, 문맥, 대동맥에서의 평균 최고 조영 증강치 역시 ioversol을 사용한 예에서 더 높게 관찰되었다. 그러나, 최고 조영 증강치에 도달하는 평균시간은 두 조영제 사이에 유의한 차이가 관찰되지 않았다. 결론: Ioversol은 후기 동맥기에서 조기 문맥기에 이르는 동안 간실질의 조영증강에 있어 iodixanol보다 통계적으로 유의한 효과를 보였다. Purpose: To determine the hepatic and vascular enhancement profiles with nonionic dimeric, iodixanol, contrast agent in the rabbit and to compare them with nonionic monomeric, ioversol, contrast agent. Materials and Methods: Seven rabbits initially underwent hepatic dynamic CT scan with either iodixanol or ioversol, followed by repeated CT scan with other unused contrast agent with one week interval between scans. Pre and post contrast attenuation values of hepatic parenchyma, aorta and portal vein were measured sequentially. The mean enhancement of the hepatic parenchyma, aorta and portal vein were compared between two agents. The mean peak enhancement and peak enhancement time of the liver, aorta, and portal vein were also compared. Results: The attenuation values of ioversol showed a greater mean hepatic enhancement than iodixanol from 18 seconds to 39 seconds after injection (from late arterial phase to early portal venous phase) with a statistical significance (p<0.05). The mean peak enhancement of hepatic parenchyma, aorta and portal vein was also greater using ioversol than iodixanol, but the mean peak enhancement times of ioversol and iodixanol were nearly identical. Conclusion: Ioversol may have the greater effects than iodixanol on hepatic tumor conspicuity, especially from late arterial phase to early portal veneous phase.

토끼 뇌감염 모델의 CT 소견과 조영제 주입 후 동맥혈의 Hounsfield Unit의 변화

하본철(Bon-Chul Ha),곽병국(Byung Kook Kwak),정지성(Jisung Jung) 한국콘텐츠학회 2012 한국콘텐츠학회논문지 Vol.12 No.9

토끼 뇌에 대장균을 주입하여 CT 소견을 알아보고, 시간에 따른 동맥혈의 하운스필드 값의 변화를 알아보고자 하였다. 토끼 두개관에 천두공(burr hole)을 뚫고 2 ~ 3 ㎜ 깊이에 대장균 1 × 10? CFU/㎖, 0.1㎖을 주입하여 뇌염증 모델을 제작하고, 조영 증강 CT와 동적 CT, 그리고 동맥혈의 CT영상을 얻었다. 조영 증강 CT에서 뇌농양, 뇌실염 그리고 뇌막염등 다양한 뇌염증 소견이 보였다. 뇌농양은 중앙부가 거의 조영되지 않고 주변부가 강하게 조영되는 전형적인 양상을 보였고, 뇌실염은 측뇌실 벽을 따라 강하게 조영되는 소견을 보였으며, 뇌막염은 종뇌와 간뇌의 접히는 부위 뇌막이 강하게 조영되었다. 동적 CT영상에서 염증 중앙부의 조영제 주입 전 HU 값은 31.01 ± 3.55였고, 주입 후 10분까지 40.36 ± 3.76으로 서서히 증가하였다. 그리고 염증 가장자리구역에서 HU 값은 조영제 주입 전에 47.23 ± 3.12였고, 조영제 주입 후약 45초에 63.59 ± 3.31로 가장 많이 증가 하였으나 이후 20분까지 약간 떨어졌다. 또한 균 주입 반대쪽 정상 뇌조직에서 측정한 HU 값은 조영제 주입 전에 39.01 ± 3.24이었고, 조영제 주입 후 약 30초에 49.01 ± 4.29로 가장 많이 조영되었고, 이후 서서히 낮아졌다. 동맥 혈액 CT에서 조영제 주입 전 HU 값은 87.78 ± 6.88이었고, 조영제 주입 후 10초부터 30초까지 급격히 증가하여 749.13 ± 98.48로 최대값을 보이고, 30초부터 45초까지 467.85 ± 62.98로 급격히 감소하며, 45초에서 60초까지는 정체기(plateau)를 보였으며, 이후 20분까지 188.28 ± 25.03으로 감소되었다. 결과적으로 대장균으로 뇌염증 모델을 만들 수 있고, 조영 증강 CT를 통하여 뇌염증의 특징적인 소견을 잘 알 수 있었으며, 동적 CT를 통해 염증 중앙부와 가장자리구역의 조영 양상을 알 수 있고, 동맥혈은 조영제 주입 후 10초부터 30초 까지 급격히 증가하다 정체기를 거쳐 서서히 감소하는 것으로 나타났다. This paper explores CT findings of a rabbit brain infection model injected with Escherichia coli and investigates the changes in Hounsfield unit (HU) of arterial blood over time. The brain infection model was produced by injecting E. coli 1×10? CFU/㎖, 0.1 ㎖ through the burr hole in the calvarium; 2 ~ 3 ㎜ in depth from the dura mater, and contrast-enhanced CT, dynamic CT and arterial blood CT images were gained. It was found that various brain infections such as brain abscess, ventriculitis and meningitis. The CT image of brain abscess showed a typical pattern which the peripheral area was strongly contrast-enhanced while the center was weakly contrast-enhanced. The CT image of ventriculitis showed a strong contrast-enhancement along the lateral ventricle wall, and the CT image of meningitis showed a strong contrast-enhancement in the area between the telencephalon and the diencephalon. In dynamic CT images, the HU value of the infection core before injecting contrast medium was 31.01 ± 3.55. By 10 minutes after the injection, the value increased gradually to 40.36 ± 3.76. The HU value in the areas of the marginal rim where was hyper-enhanced showed 47.23 ± 3.12 before contrast injection, and it increased to 63.59 ± 3.31 about 45 seconds after the injection. In addition, the HU value of the normal brain tissue opposite to the E. coli. injected brain was 39.01 ± 3.24 before the injection, but after the contrast injection, the value increased to 49.01 ± 4.29 in about 30 seconds, and then it showed a gradual decline. In the arterial blood CT, the HU value before the contrast injection was 87.78 ± 6.88, and it increased dramatically between 10 to 30 seconds until it reached a maximum value of 749.13 ± 98.48. Then it fell sharply to 467.85 ± 62.98 between 30 seconds to 45 seconds and reached a plateau by 60 seconds. Later, the value showed a steady decrease and indicated 188.28 ± 25.03 at 20 minutes. Through this experiment, it was demonstrated that the brain infection model can be produced by injecting E. coli., and the characteristic of the infection model can be well observed with contrast-enhanced CT scan. The dynamic CT scan showed that the center of the infection was gradually contrast-enhanced, whereases the peripheral area was rapidly contrast-enhanced and then slowly decreased. As for arterial blood, it increased significantly between 10 seconds to 30 seconds after the contrast medium injection and decreased gradually after reaching a plateau.

토끼 뇌종양 모델에서의 관류 CT 영상에 관한 연구

하본철(Bon-Chul Ha),곽병국(Byung Kook Kwak),정지성(Jisung Jung),임청환(Cheong-Hwan Lim),정홍량(Hong-Ryang Jung) 대한방사선과학회(구 대한방사선기술학회) 2012 방사선기술과학 Vol.35 No.2

We investigated the vascular characteristics of tumors and normal tissue using perfusion CT in the rabbit brain tumor model. The VX2 carcinoma concentration of 1×10⁷ cells/㎖(0.1 ㎖) was implanted in the brain of nine New Zealand white rabbits (weight: 2.4 ㎏-3.0 ㎏, mean: 2.6 ㎏). The perfusion CT was scanned when the tumors were grown up to 5 ㎜. The tumor volume and perfusion value were quantitatively analyzed by using commercial workstation (advantage windows workstation, AW, version 4.2, GE, USA). The mean volume of implanted tumors was 316±181 ㎣, and the biggest and smallest volumes of tumor were 497 ㎣ and 195 ㎣, respectively. All the implanted tumors in rabbits are single-nodular tumors, and intracranial metastasis was not observed. In the perfusion CT, cerebral blood volume (CBV) were 74.40±9.63, 16.08±0.64, 15.24±3.23 ㎖/100g in the tumor core, ipsilateral normal brain, and contralateral normal brain, respectively (p≦0.05). In the cerebral blood flow (CBF), there were significant differences between the tumor core and both normal brains (p≦0.05), but no significant differences between ipsilateral and contralateral normal brains (962.91 ± 75.96 vs. 357.82 ± 12.82 vs. 323.19 ± 83.24 ㎖/100g/min). In the mean transit time (MTT), there were significant differences between the tumor core and both normal brains (p≦0.05), but no significant differences between ipsilateral and contralateral normal brains (4.37 ± 0.19 vs. 3.02 ± 0.41 vs. 2.86 ± 0.22 sec). In the permeability surface (PS), there were significant differences among the tumor core, ipsilateral and contralateral normal brains (47.23±25.45 vs. 14.54 ± 1.60 vs. 6.81 ± 4.20 ㎖/100g/min)(p≦0.05). In the time to peak (TTP) were no significant differences among the tumor core, ipsilateral and contralateral normal brains. In the positive enhancement integral (PEI), there were significant differences among the tumor core, ipsilateral and contralateral brains (61.56 ± 16.07 vs. 12.58 ± 2.61 vs. 8.26 ± 5.55 ㎖/100g). (p≦0.05). In the maximum slope of increase (MSI), there were significant differences between the tumor core and both normal brain(p≦0.05), but no significant differences between ipsilateral and contralateral normal brains (13.18±2.81 vs. 6.99±1.73 vs. 6.41±1.39 HU/sec). Additionally, in the maximum slope of decrease (MSD), there were significant differences between the tumor core and contralateral normal brain(p≦0.05), but no significant differences between the tumor core and ipsilateral normal brain(4.02 ± 1.37 vs. 4.66 ± 0.83 vs. 6.47 ± 1.53 HU/sec). In conclusion, the VX2 tumors were implanted in the rabbit brain successfully, and stereotactic inoculation method make single-nodular type of tumor that was no metastasis in intracranial, suitable for comparative study between tumors and normal tissues. Therefore, perfusion CT would be a useful diagnostic tool capable of reflecting the vascularity of the tumors. VX2 암종을 이식한 토끼 뇌종양 모델에서, perfusion CT(computed tomography, CT)를 이용하여 종양과정상 뇌조직의 혈류 특성을 알아보고자 하였다. 체중 2.4 ~ 3.0 ㎏(평균 2.6 ㎏)의 토끼(New Zealand white rabbit) 수놈 9마리를 대상으로, 토끼 뇌에 VX2 세포 현탁액 1 × 10⁷ cells/㎖, 0.1 ㎖을 이식하고 종양이 5 ㎜ 정도 크기로 자라면 perfusion CT를 시행 하였다. GE사의 AW(advantage windows workstation, version 4.2)로 종양의 용적과 perfusion 값을 산출 하였다. 뇌종양의 평균 용적은 316 ± 181 ㎣이었고, 가장 큰 종양은 497 ㎣, 가장 작은 종양은 195 ㎣이었다. 이식된 종양 모두 단일 결절형으로 만들어졌고, 두개강 내로 전이는 발견되지 않았다. perfusion CT에서 종양 중심부의 혈류량(cerebral blood volume, CBV)은 74.40 ± 9.63 이었고, 종양쪽 정상 뇌조직에서는 16.08 ± 0.64 이었으며, 종양 반대쪽 정상 뇌조직에서는 15.24 ± 3.23이었다. 혈류 속도(cerebral blood flow, CBF)는 종양 중심부에서 962.91 ± 75.96 이였고, 종양쪽 정상 뇌조직에서는 357.82 ± 12.82 이었으며, 종양 반대쪽 정상 뇌조직에서는 323.19 ± 83.24 이었다. 평균 통과시간(mean transit time, MTT)은 종양 중심부에서 4.37 ± 0.19 이었고, 종양쪽 정상 뇌조직에서는 3.02 ± 0.41 이었으며, 종양 반대쪽 정상 뇌조직에서는 2.86 ± 0.22 이었다. 투과성 표면적(permeability surface, PS)은 종양중심부에서 47.23 ± 25.45 이었고, 종양쪽 정상 뇌조직에서는 14.54 ± 1.60 이었으며, 종양 반대쪽 정상 뇌조직에서는 6.81 ± 4.20이었다. 또한, 종양 중심부에서 최고치 도달 시간(time to peak, TTP)은 19.33 ± 0.42 이었고, 종양쪽 정상 뇌조직에서는 16.43 ± 1.72 이었으며, 종양 반대쪽 정상 뇌조직에서는 15.14 ± 0.88이었지만 통계적으로 유의하지 않았다. PEI(positive enhancement integral, PEI)은 종양 중심부에서 61.56 ± 16.07이었고, 종양쪽 정상 뇌조직에서는 12.58 ± 2.61 이었으며, 종양 반대쪽 정상 뇌조직에서는 8.26 ± 5.55 이었다. 최대 증가 기울기(maximum slope of increase, MSI)는 종양 중심부에서 13.18 ± 2.81 이었고, 종양쪽 정상 뇌조직에서는 6.99 ± 1.73 이었으며, 종양 반대쪽 정상 뇌조직에서는 6.41 ± 1.39 이었다. 최대 감소 기울기(maximum slope of decrease, MSD)는 종양 중심부에서 4.02 ± 1.37 이었고, 종양쪽 정상 뇌조직에서는 4.66 ± 0.83 이었으며, 종양 반대쪽 정상 뇌조직에서는 6.47 ± 1.53 으로 나타났다. 결과적으로 정위적(stereotactic)으로 이식된 종양은 단일 결절형으로 두개강 내에 전이가 없어 정상 조직과 종양 조직의 비교 연구에 적합하며, perfusion CT 에서 얻어진 매개 변수(parameter)들은 종양과 정상 조직의 혈관 관류 상태 차이를 잘 반영해 주었다.

심포지움 : 토끼 신동맥에 주입된 키토산 색전물질의 시간 경과에 따른 병리적 변화

한상문(Sang Mun Han),김용범(Yong Beom Kim),곽병국(Byung Kook Kwak),심형진(Hyung Jin Shim),안병제,이용철(Yong Chul Lee),도쿠라세이치(Tokura Seiichi) 한국키틴키토산학회 2002 한국키틴키토산학회지 Vol.7 No.1

Tetracycline을 포접한 Chitin 차페막의 약물 방출특성

한상문 ( Sang Mun Han ),손상현 ( Sang Hyun Son ),조지연 ( Ji Youn Cho ),최한영 ( Han Young Choi ),강병원 ( Byoung Won Kang ),심형진 ( Hyung Jin Shim ),곽병국 ( Byung Kook Kwak ),이승진 ( Seung Jin Lee ) 한국키틴키토산학회 2003 한국키틴키토산학회지 Vol.8 No.1

Chitin은 생체친화성이 높고, 독성을 유발하지 않는다. 본 연구에서는 Chitin을 calcium chloride dihydrate saturated methanol 용액에 녹여 Chitin 차폐막에 양이온성 항생제인 TC을 포접시켜 TC의 용리 특성을 조사하였다. Chitin 차폐막에 포접시켜 칼슘을 제거한 결과 93% 이상 차폐막속에 포접됨을 알았으며 TC 감수성균의 대부분에 대하여 MIC 농도를 유지하면 방출됨을 확인하였다. Chitin is well known that it is biocompatible, biodegradable and nontoxicity. In this study, chitin was dissolved in a novel solvent newly developed, calcium chloride dihydrate saturated methanol solution. The chitin dope casted into a membrane which was subject to adsorption and release tests with tetracycline. Tetracycline which is cationic antibiotic substance was found to be adhered more than 90% to chitin membrane and was released at the level of minimum inhibitory concentration(MIC) against the tetracycline killing microorgrans. It was concluded that controlled release and adherence of any antibiotic substances from or on chitin membrane depend upon their ionic characters(Carboxy1 group of soluble polysaccharide) and salt concentration of eluents.

가토에서 생검총을 이용한 폐생검후 NBCA 충전에 관한 실험적 연구 : 가토폐 생검 후 NBCA 충전

곽병국,정걸호,최치훈,이창준,장희진,심형진 중앙대학교 의과대학 의과학연구소 1999 中央醫大誌 Vol.24 No.1

Pneumothorax and hemorrhage are frequent complications after percutaneous lung biopsy. The purpose of this study is to evaluate the effects of NBCA on plugging the biopsy tract in rabbit lung and pathologic changes caused by NBCA. The right lungs of 14 New Zealand White rabbit were biopsied with an 18G biopsy gun. The biopsy tracts were filled with none(control group) and NBCA mixed with lipiodol(1:1) in 7 rabbits respectively. CT scans were performed immediatoly and 24 hours after procadure. The rabbits were sacrificed and pathologically cvaluated for 17 days. Each pneumothorax and pulmonary heomrrhage as a complication after gun biopsy was seen in 4 cases (57.1%) of the control group(n=7). In NBCA group(n=7), pneumothorax was seen in 2 cases(28.6%) and hemorrhage was seen in 1 case(14.3%)(p>0.05). NBCA filled the biopsy tract and pleural space, and pleural adhesion was seen in 1 case of 2 rabbits complicated by pneumothorax. Pathologically the hemorrhage was more significant in control group(100%) than in NBCA group(28.6%). But the inflammation was 28.6% in control group and 100% in NBCA group. The necrosis, foreign body reaction and fibrosis were similar in both groups. In conclusion, NBCA would be helpful to prevent the pneumothorax and hemorrhage after a percutaneous lung biopsy.

간내담관의 해부학적 변이와 잔류담석의 분포 : Radiological Anatomy and Prevalence of Intrahepatic Stones

곽병국,이화연,이종범,심형진,김영구,김선상 중앙대학교 의과대학 의과학연구소 1995 中央醫大誌 Vol.20 No.2

The purpose of this study was to know the confluental anatomy of the intrahepatic biliary duct and the occurrence of the stone according to each segmental biliary duct in the recurrent pyogenic cholangitis. We classified 139 of T-tube cholangiography(AP and oblique view the confluence of intrahepatic biliary tracts. Prevalence, size and number of the stones were evaluated according to each hepatic segmental duct. The confluence of the right and left main hepatic ducts was the most popular type(57.6%). The right main hepatic duct was abscent in 38.8% and the left main hepatic duct was abscent in 2.9%. The occurence of the stones was high in left lateral segmental duct(50.4%) and then right posterior segmental duct(32.4%), right anterior segmental duct(23.0%) and left medial segmental duct(12.2%) in descending order. There were no stones in caudate lobe. There was no difference in the size according to each segmental duct. he number of the stones was high in right posteior duct(17.5) and left lateral duct(17.1). But there was no statistical meaning in size and number. The incidence of the each confluental type was similar to other previous study. There was no stones in caudate lobe. The longer and wider of the duct, the more stasis of the bile, the more stones occured. There was no size difference. The number of the stones is high in right posterior and left lateral duct, but there was no statistical meaning.

Segmental Prevalence and Extraction Rate of Retained Intrahepatic Stone

Kwak, Byung Kook,Lee, Jong Beum,Joo, Sang Shin,Lee, Hwa Yeon,Shim, Hyung Jin,Kim, Kun Sang,Lee, Yong Chul 중앙대학교 의과대학 의과학연구소 1996 中央醫大誌 Vol.21 No.2

간내 잔류담석의 간 구역별 빈도와 제거율과 실패원일을 알고자 한다. 담석증으로 수술을 받고 T자관을 통하여 잔류담석 제거술을 시행 받은 환자중 간내담도에 잔류담석이 있던 126명을 후향적으로 담도조영사진을 분석하였다. 간내담도별 잔류 단석의 빈도와 제거율은 좌외측(left lateral)이 각각 54.0%, 91.1% ; 우후(right posterior)가 38.1%, 81.2% ; 우전(right anterion)이 26.2%, 93.8% ; 좌 내측(left medial)이 14.3%, 77.7%를 보였다. 전체 제거율은 85.6%이었다. 미상엽은 모든 예에서 간내 담석이 없었다. 제거 실패의 주된 원인은 담도 협착과 매복된 담석이었다. 우후와 좌내측 간내담도에서는 고유한 담도의 굴곡이 또 하나의 실패의 주된 원인이었다. 결론적으로 좌외측 간내담도가 담석의 빈도가 가장 높고 우후, 우전, 좌내측 간내담도의 순서로 높았다. 우후와 좌내측 간내담도의 담석제거율이 우전, 좌외측 보다 낮았으며, 이것은 고유한 굴곡 대문으로 설명된다. To evaluate the hepatic segmental prevalence and the extraction rate of the retained intrahepatic stones on cholangiogram and the cause of failure of percutaneous stone removal through a T-tube tract. One hundred and twenty-six patients who had undergone the extraction of the retained intrahepatic stones were evaluated. Selective segmental cholangiogrmas were obtained for each segmental prevalence by using a pre-shaped 10F catheter. The results of the segmental extraction rate and the cause of failure were also evaluated after completing the stone removal session. The segmental prevalence and the extraction rate were 54.0% and 91.1% in the left lateral(LL), 38.1% and 81.2% in the right posterior(RP), 26.2% and 93.8% in the right anterior(RA), 14.3% and 77.7% in the left medial(LM) segmental duct, respectively. The total extraction rate was 85.6%. The caudate lobe had no stone in all cases. The main causes of extraction failure were stricture and stone impaction. In the RP and the LM segmental duct, duct angulation was another amin cause of failure. The prevalence of retained stones is highest in the LL segmental duct, the RP, the RA and the LM segmental duct, in descending order. There was no stone in the caudate lobe. The extraction in the RP and LM segmental ducts is more difficult than in the RA and LL segmental ducts. This result can be explained by the natural anatomical angulation of these ducts.

토끼 콩팥에 대한 키토산 미세구의 색전 효과

이종익,곽병국,심형진,이종범,이용철,유재형,한상문 중앙대학교 의과대학 의과학연구소 2003 中央醫大誌 Vol.28 No.1

The aim of the study was to evaluate the possibility of therapeutic use of chitosan microspheres as a new embolic material. Twenty four New Zealand white rabbits were divided into four groups. Polyvinyl alhocol (PVA) particles (150-250 ㎛ ) was used in group 1. Chitosan microspheres were used in group 2 (150-250 ㎛ ), group 3 (250-355 ㎛) and group 4 (355-500 ㎛) respectively. Arteriography of right kidney was performed using 4 F cobra catheter. Embolization was continued until complete occlusion of the right renal artery was achieved. Catheters were tested whether the lumen is obstructed by embolic materials during and after embolization. One animal was sacrificed in each group on the 1st and 3rd day, 1st, 2nd, 4th, and 8th week respectively. Basic hematologic and blood chemisty were analyzed, and gross and microscopic pathologic findings were observed. Chitosan microspheres were round to oval shape, and had smooth surface and even size under the light microscope. Successful embolizations were achieved in all twenty four rabbits. On gross pathologic examination, all chitosan microsphere groups showed no differences from PVA particle group in renal contraction and discoloration. Histologically chitosan microsphere groups had a higher incidence of vasculitis. but did not show any recanalization in comparison with PVA particle group. Hematologic and blood chemisty showed no significant abnormal change in all groups. In conclusion, effective, technically easy and safe embolizations were achieved with chitosan microspheres in rabbit kidney. Chitosan microspheres might be a good embolic material.