Gi-Young Ko

Asan Medical Center, Sŏul, Seoul, South Korea

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Publications (142)355.63 Total impact

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    ABSTRACT: A double stent system (covered stent in uncovered stent) was designed to provide long-term patency without tumor ingrowth or stent-related complications, such as stent migration, cholecystitis, or pancreatitis.
    Acta radiologica (Stockholm, Sweden : 1987). 09/2014;
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    ABSTRACT: Although dysfunctional radiocephalic arteriovenous fistulas (RCAVFs) are typically treated surgically, the endovascular approach is also considered suitable. The aim of this retrospective study was to compare the cumulative patency rates following surgical and endovascular salvaging of dysfunctional RCAVFs, and to evaluate whether the maturity of vascular access sites at the time of treatment influenced the outcomes.
    Annals of Vascular Surgery 07/2014; · 0.99 Impact Factor
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    ABSTRACT: To evaluate the safety and efficacy of transcatheter arterial chemoembolization (TACE) in patients with infiltrative hepatocellular carcinoma (HCC) and to identify the prognostic factors associated with patient survival.
    Korean journal of radiology: official journal of the Korean Radiological Society 07/2014; 15(4):464-71. · 1.32 Impact Factor
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    ABSTRACT: To evaluate the safety and efficacy of transarterial nephrectomy, i.e., complete renal artery embolization, as an alternative to surgical nephrectomy.
    Korean journal of radiology: official journal of the Korean Radiological Society 07/2014; 15(4):472-80. · 1.32 Impact Factor
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    ABSTRACT: To assess the safety and efficacy of transcatheter arterial embolization (TAE) for the management of secondary postpartum hemorrhage (PPH) and to determine the factors associated with the clinical outcomes.
    Journal of vascular and interventional radiology: JVIR 06/2014; · 1.81 Impact Factor
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    ABSTRACT: Objective: To evaluate the overall and cumulative incidence, degree, interval change, and predictors of hepatic arterial injury (HAI) after cisplatin and gelfoam-based, transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) Methods: A total of 205 HCC patients who underwent three or more sessions of TACE without additional surgical or local treatment, were included. HAI was evaluated at each segment of the hepatic artery using a three-grade scale: 1(slight wall irregularity); 2(overt stenosis); and 3(occlusion). HAI interval change was categorized into three groups: progression; stable-state; and improvement. Cumulative incidence of HAI was analyzed using Kaplan-Meier method, and predictors of HAI (patient age, sex, portal vein thrombosis, and Child-Pugh classification) were analyzed by univariate logistic regression. Results: HAI occurred in 50 of 205 study patients (24.4%). The cumulative incidence of HAI during five sessions of TACE was 16.0%(95%CI,10.21-21.77), 52.1%(95%CI,37.83-66.29) during 10 sessions, and 68.0%(95%CI,67.62-88.46) during 15 sessions. Initial HAI was interpreted as grades 1, 2, and 3 in 11(22.0%), 17(34.0%), and 22(44.0%) patients, respectively. When the interval change was assessed in 48 patients with available follow-up TACE, 40(83.3%) were included in the progression, two(4.2%) in the stable-state, and six(12.5%) in the improvement groups. The univariate analysis used to determine the predictors of HAI revealed no significant predictors. Conclusions: 3 or more sessions of TACE, the incidence of HAI is 24%. Increasing TACE causes increased incidence of HAI. The initial presentation was most commonly grade 3, and 12.5% of the patients with HAI showed improvement of the HAI grade during follow-up TACE.
    The British journal of radiology. 06/2014;
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    ABSTRACT: OBJECTIVES:To compare the effectiveness of transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) for treating small (≤2 cm) hepatocellular carcinomas (HCCs).METHODS:This retrospective study consisted of 287 patients (mean age, 57.1 years; age range, 29-84 years; 221 men, 66 women; 73.5% with HBV; 100% with liver cirrhosis) with Barcelona Clinic Liver Cancer very early-stage HCC (≤2 cm single HCC) who were initially treated with TACE (n=122) or RFA (n=165). The primary study end point was overall patient survival. Secondary study end points were time to progression and tumor response.RESULTS:The RFA and TACE groups were well balanced in terms of baseline variables. The two groups did not differ significantly in overall survival (P=0.079) or major complication (P>0.999) rates. The respective cumulative survival rates at 1, 3, 5, and 8 years were 97.6, 86.7, 74.5, and 60.0% for RFA and 93.4, 75.4, 63.1, and 51.1% for TACE. Their objective tumor regression (complete or partial response) rates were 100% (165/165) and 95.9% (117/122), respectively (P=0.013). The median times to progression for RFA and TACE were 27.0±3.8 (95% confidence intervals (CIs): 19.6-34.4) and 18.0±2.9 (95% CIs: 12.2-23.8) months, respectively. RFA yielded a significantly longer time to progression (P=0.034).CONCLUSIONS:TACE may be a viable alternative treatment for ≤2 cm HCCs when RFA is not feasible.Am J Gastroenterol advance online publication, 17 June 2014; doi:10.1038/ajg.2014.152.
    The American journal of gastroenterology. 06/2014;
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    ABSTRACT: Purpose: To evaluate the efficacy and safety of transfemoral liver biopsy using a Quick-Core biopsy needle in selected living donor liver transplantation (LDLT) recipients. Materials & methods: Eight LDLT recipients underwent nine sessions of transfemoral liver biopsy. Six patients had received modified-right-lobe LDLT and two patients had received dual-left-lobes LDLT. Indications for transfemoral liver biopsy were patients with acute HV angle relative to the IVC on the coronal plane and/or patients with thin (<10mm) liver parenchyma surrounding a HV to be biopsied on enhanced computed tomography. Under fluoroscopic guidance, the right inferior HV in the modified-right-lobe or the left HV in the right-sided left lobe with cranial orientation was negotiated using a 5-F catheter via the common femoral vein. Then, a stiffening cannula was introduced into the HV over a stiff guide wire. Needle passage was then performed with an 18- or 19-G Quick-Core biopsy needle. Results: Technical success was achieved in all sessions without major complications. The median number of needle passages was four (range, 2-6). The median total length of obtained liver specimens in each session was 44 mm (range, 24-75 mm). The median number of portal tracts was 18 (range, 10-29) and the obtained liver specimens were adequate for histological diagnosis in all sessions. Conclusion: Transfemoral liver biopsy using a Quick-Core biopsy needle is an effective and safe alternative for obtaining a liver specimen when standard transjugular liver biopsy is not feasible because of an unfavorable HV angle relative to the IVC and/or thin liver parenchyma surrounding a HV. Liver Transpl , 2014. © 2014 AASLD.
    Liver Transplantation 06/2014; · 3.94 Impact Factor
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    ABSTRACT: To evaluate the safety and clinical efficacy of transcatheter uterine artery embolization (UAE) for post-myomectomy hemorrhage.
    Korean journal of radiology: official journal of the Korean Radiological Society 05/2014; 15(3):356-63. · 1.32 Impact Factor
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    ABSTRACT: Patent portal vein (PV) and adequate portal inflow is essential for successful living donor liver transplantation (LDLT). In extensive portal vein thrombosis (PVT) patients, however, complete PV thrombectomy is not feasible particularly at intrapancreatic portion, and subsequently portal flow steal through preexisting sizable collaterals or rethrombosis can occur. To overcome those problems, we introduced interruption of sizable collaterals and intraoperative cine-portogram (IOP), which is useful for diagnosis and treatment of residual PVT and sizable collaterals.
    Transplantation 04/2014; 97 Suppl 8:S23-30. · 3.78 Impact Factor
  • Gi-Young Ko, Kyu-Bo Sung
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    ABSTRACT: Although endoscopic treatment has become the first choice to treat biliary complications, percutaneous transhepatic treatment still has important roles to treat biliary stricture or leak after living donor liver transplantation. This study reviewed a total of 527 recipients who had undergone percutaneous transhepatic treatment to treat biliary stricture (n=498) and leaks (n=29). Percutaneous transhepatic treatment included percutaneous transhepatic biliary drainage, perihepatic biloma drainage, balloon dilation of biliary stricture, and drainage catheter interposition or retrievable covered stent placement across a stricture or leak segment. Clinical success was achieved in 440 (88.4%) recipients with biliary stricture and 19 (65.5%) recipients with bile leaks. Percutaneous transhepatic treatment seems to be an effective alternative for treating biliary complications resistant to or inaccessible by endoscopic treatment.
    Transplantation 04/2014; 97 Suppl 8:S43-6. · 3.78 Impact Factor
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    ABSTRACT: Purpose: To evaluate the technical feasibility and clinical outcome of bilateral uterine artery embolization (UAE) as a first-line therapeutic option for bleeding uterine arteriovenous malformation (AVM). Materials and Methods: Between 2002 and 2012, 19 patients were diagnosed with acquired uterine AVM clinically and through imaging studies. The clinical characteristics, angiographic features, technical success rate of embolization, procedure-related complications, imaging, and clinical follow-up data were assessed. Clinical success was defined as immediate symptomatic resolution with disappearance of vascular abnormality on subsequent imaging studies. Results: A total of 20 bilateral UAE, with or without embolization of extra-uterine feeders, were performed as the first-line treatment. Technical and clinical success rate was 90.0% (18/20) and 89.5% (17/19), respectively. Embolization was incomplete in two patients who had residual extra-uterine fine feeders to the AVM or a procedure- related complication (ruptured uterine artery); the former showed slow regression of the vascular malformation during the observation period, while the latter underwent a successful second bilateral UAE. Immediate clinical success was achieved in the remaining 17 patients after a single session and no recurrence of bleeding was found. Recovery to normal menstrual cycle was seen in all 17 patients with clinical success within one or two months, two of whom subsequently had uneventful intrauterine pregnancies carried to term. Conclusion: Bilateral UAE is a safe and effective first-line therapeutic option for the management of bleeding uterine AVMs. However, incomplete embolization due to unembolizable feeders or difficult access into the uterine artery may lead to suboptimal treatment.
    Yonsei medical journal 03/2014; 55(2):367-73. · 0.77 Impact Factor
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    ABSTRACT: Although the use of polytetrafluoroethylene (PTFE)-covered biliary stents has proven to be feasible for the treatment of benign and malignant biliary disease, less is known regarding the outcomes of percutaneous placement of a covered stent in patients with malignant duodenobiliary obstruction. To investigate the technical and clinical efficacy of the percutaneous placement of a PTFE-covered biliary stent in patients with malignant duodenobiliary obstruction. From April 2007 to September 2012, the medical records of 45 consecutive patients with malignant duodenobiliary obstruction were retrospectively reviewed. All percutaneous biliary stent deployment was performed using PTFE-covered stents, whereas duodenal stent insertion was performed either fluoroscopically or endoscopically using covered or uncovered stents. Biliary stent deployment was technically successful in all patients. None of the stents migrated after deployment. Procedure-related minor complications, including self-limiting hemobilia, occurred in three (7%) patients. Successful internal drainage was achieved in 39 (87%) of the 45 patients. The median survival time after biliary stent placement was 62 days (95% confidence interval, 8-116 days), and the cumulative stent patency rates at 1, 3, 6, and 12 months were 96%, 92%, 75%, and 38%, respectively. The causes of biliary stent dysfunction included stent occlusion caused by a subsequently inserted duodenal stent (n = 7), food impaction (n = 3), and sludge incrustation (n = 1). One patient developed acute cholecystitis 131 days after biliary stent placement and underwent percutaneous transhepatic gallbladder drainage. Percutaneous insertion of a PTFE-covered stent is a safe and effective method for palliative treatment of patients with malignant duodenobiliary obstruction. If possible, subsequent biliary stent insertion is preferable in order to prevent possible biliary stent dysfunction caused by subsequent insertion of a duodenal stent.
    Acta Radiologica 02/2014; · 1.33 Impact Factor
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    ABSTRACT: The meso-Rex shunt is used to safely and effectively treat patients with portal hypertension due to extrahepatic portal vein obstruction. In the standard meso-Rex shunt technique, the patient's own internal jugular vein is used as a vascular autograft. Inevitably, such a procedure requires neck exploration and sacrifice of the internal jugular vein. Here, we present a case of a 20-year-old man with idiopathic extrahepatic portal vein obstruction, who was treated with a new technique of transposition of the coronary vein, which is enlarged in most cases of portal hypertension, as an alternative to the standard meso-Rex shunt technique. The transposition of the coronary vein into the Rex recessus is more efficient and less invasive than harvesting an autologous vein graft. Therefore, this technique simplifies the procedure and should be used when possible.
    Annals of surgical treatment and research. 02/2014; 86(2):105-8.
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    ABSTRACT: To evaluate the safety and efficacy of unilateral covered stent placement in patients with malignant superior vena cava (SVC) syndrome. Between October 2008 and November 2012, expanded polytetrafluoroethylene-covered stent placement for malignant SVC syndrome was performed in 40 consecutive patients (35 men and five women; mean age, 61.4 years; range, 35-81 years). All covered stents were unilaterally placed within the SVC or across the venous confluence when needed to relieve venous obstruction and prevent tumor overgrowth, regardless of patency of contralateral brachiocephalic veins. Stent placement was technically successful in all patients. There were no major complications. Of the 37 patients symptomatic prior to stent placement, 34 (92%) experienced complete symptomatic relief 1-8 days after stent placement. Of the 29 patients who underwent covered stent placement across the venous confluence, nine patients had patent contralateral brachiocephalic veins prior to stent placement. However, no sign of SVC obstruction or contralateral upper extremity venous thrombosis was observed during the follow-up period. Kaplan-Meier analysis revealed median patient survival of 163 days. Stent occlusion occurred in four (10%) of 40 patents. Cumulative stent patency rates at 1, 3, 6, and 12 months were 95%, 92%, 86%, and 86%, respectively. Unilateral covered stent placement appears to be a safe and effective method for treating malignant SVC syndrome, despite the location of SVC occlusion.
    Korean journal of radiology: official journal of the Korean Radiological Society 01/2014; 15(1):87-94. · 1.32 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate retrospectively the results of PTA for late-onset PV complications after pediatric LDLT and to assess whether a meso-Rex shunt is a viable option for treating restenosis of the PV after PTA in selected cases. Seventy-five children who underwent adult-to-child LDLT were included in this study, and there were six late-onset PV complications (8.0%). The initial therapeutic approach was PTA, with or without stent: PTA with balloon dilation for three children, PTA with stent placement for one child, and failure to cannulate the occluded PV for two children. A meso-Rex shunt was performed in the two children after failed PTA: One suffered complete obstruction of the main PV, and the other, restenosis with total thrombosis after PTA with stent. The PTA was a technical and clinical success in four with PV stenosis of the six patients (66.7%), and successful application of a meso-Rex shunt in the other two children resulted in restoration of PV flow. In conclusion, PTA is a safe and effective procedure for treating late-onset PV stenosis after pediatric LDLT. However, in growing pediatric recipients with restenosis of the PV after PTA or chronic PV thrombosis, a meso-Rex shunt may be a better choice for late-onset PV complications.
    Pediatric Transplantation 12/2013; · 1.50 Impact Factor
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    ABSTRACT: PURPOSE The purpose of this study is to investigate radiologic and histologic features of biliary intraductal metastasis from advanced gastric cancer in 24 patients with biliary obstruction and clinical outcomes after metallic stent placement. METHOD AND MATERIALS Patient papulation: This retrospective study was approved by Institutional Review Board of our institution and written informed consent was waived. Between August 2003 and August 2012, 24 consecutive patients with obstructive jaundice related to biliary intraductal metastasis from advanced gastric cancers were enrolled. Imaging Methods and Diagnosis PTBD, Biliary Biopsy, and Pathologic Analysis Metallic Stent Placement Endpoints of stent placement and Statistical analysis RESULTS Imaging and pathologic Characteristics: uniform concentric linear (n=17) or band-like (n=7) enhanced wall thickening. 20 (83.3%) had cystic ductal lesions contiguous with the intraductal lesions. The level of biliary obstruction was hilar in 13 (54.2%) patients and non-hilar in 11 (45.8%). Ninety (79.2%) patients had lymph node metastasis around the biliary system.The submucosal fibrosis was universal feature in all biopsied cases (n=6), regardless of the malignant or atypical cells, and none of the cases shows biliary mucosa disruption by the malignant cells. Outcomes of Metallic Stent Placement: Stent occlusion was observed in four (17%) patients treated with PTBD, in three owing to sludge incrustation and in one owing to tumor overgrowth, 49—278 days (mean, 168 days) after stent placement. Mean stent patency time was 341 days (95% CI 272–410 days) and cumulative stent patency rates at 3, 6, 9, and 12 months were 95%, 88%, 78%, and 62%, respectively CONCLUSION In conclusion, imaging and pathologic characteristics of biliary intraductal metastasis from advanced gastric cancer are uniform enhanced biliary wall thickening, and submucosal malignant cells and fibrosis without any disruption of biliary epithelial layer. Moreover, uncovered metallic stent placement was safe and effective methods for palliative treatment in patients with biliary intraductal metastasis cause by advanced gastric cancer. CLINICAL RELEVANCE/APPLICATION The clinical outcomes after uncovered stent placement and pathologic proof may give an explanation.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: To evaluate the safety and efficacy of modified cisplatin-based transcatheter arterial chemoembolization for inoperable hepatocellular carcinomas (HCCs) larger than 5 cm in diameter, and the factors associated with tumor response and survival. From January 2007 to November 2009, 163 patients who underwent modified cisplatin-based chemoembolization for inoperable large HCCs were evaluated. Predominant tumors were as large as 25 cm (median, 8.6 cm). Seventy-nine patients had a solitary tumor, and 84 had two or more tumors. Tumor response was evaluated per modified Response Evaluation Criteria In Solid Tumors. After chemoembolization, 65% of patients showed a tumor response. On multivariate analysis, tumor size (P < .001) and portal vein (PV) invasion (P = .017) were significant factors for tumor response. After chemoembolization, 97% of patients (56 of 58) with PV invasion received additional radiation therapy for PV tumor thrombosis. Median survival time was 15.8 months. On multivariate analysis, Child-Pugh class (P = .001), surgical resection (P = .003) or radiofrequency (RF) ablation (P = .018) after chemoembolization, and tumor response (P = .002) were significant factors for patient survival after chemoembolization. Major complications (N = 5) included acute renal failure (n = 3), cholecystitis with hepatic abscess (n = 1), and intractable pleural effusion (n = 1). Transcatheter arterial chemoembolization is safe and effective for large HCCs. Tumor size and PV invasion are significant predictors of tumor response and, Child-Pugh class A disease, surgical resection after chemoembolization, RF ablation after chemoembolization, and tumor response are good prognostic factors for survival.
    Journal of vascular and interventional radiology: JVIR 08/2013; · 1.81 Impact Factor
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    ABSTRACT: The aim of our present study was to review the experiences of a living donor-dominant transplantation program for children with acute liver failure (ALF). Data were derived from the retrospective chart review of 50 children with ALF in a major liver center, Korea. A total of 50 children with ALF underwent 47 (94%) primary living donor liver transplantations and 3 (6%) cadaveric liver transplantations. The cumulative survival rates of the grafts at 1 and 5 years were 81.9% and 79.2%, respectively. The overall retransplantation rate was 12%. The cumulative survival rates of these patients at 1 and 5 years were all 87.9%. Most incidents of mortality followed the failure of the preceding graft. We observed no mortalities among donors. Based on multivariate analysis, children who had pretransplant thrombocytopenia or had to use the molecular adsorbent recycling system preoperatively were related to the graft loss. Age <2 years and a hyperacute onset (within 7 days) of hepatic encephalopathy were associated with pretransplant thrombocytopenia. Living donor-dominant transplantation program in the present study demonstrates tolerable achievements in terms of clinical outcomes of recipients and donors. However, putative factors, such as pretransplant thrombocytopenia, seem to play unclear roles in a poor prognosis following transplantation.
    Journal of pediatric gastroenterology and nutrition 08/2013; · 2.18 Impact Factor
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    ABSTRACT: To investigate the outcomes of percutaneous metallic stent placement in patients with malignant bilioenterostomy obstruction and to assess the risk factors influencing stent patency. From August 2008 to January 2012, 53 patients with malignant bilioenterostomy obstructions were treated with percutaneous placement of biliary metallic stents; this included expanded polytetrafluoroethylene (ePTFE)-covered stent placement in 36 patients and uncovered stent placement in 17 patients. A total of 75 stents were successfully placed in 53 patients. No major complications occurred in any patients, and minor complications occurred in nine patients (17%). The mean serum bilirubin level, which was 3.6 mg/dL ± 0.7 before drainage, decreased significantly to 2.5 mg/dL ± 0.4 at 1 month after stent placement (P = .041). Successful internal drainage was achieved in 44 of the 53 patients (83%). Kaplan-Meier analysis showed a median overall survival time of 145 days (95% confidence interval, 100-190 d), a median stent patency time of 313 days (95% confidence interval, 46-580 d), and cumulative stent patency rates at 1, 3, 6, 9, and 12 months of 91%, 75%, 64%, 56%, and 45%, respectively. Multivariate Cox regression analysis showed that the use of uncovered stents (odds ratio, 2.924; P = .033) was the only significant independent factor associated with stent occlusion. Percutaneous metallic stent placement is a safe and effective method for the treatment of patients with malignant bilioenterostomy obstruction. Moreover, as uncovered stent placement is the only significant independent factor associated with stent occlusion, ePTFE-covered stent placement is preferable in these patients.
    Journal of vascular and interventional radiology: JVIR 07/2013; · 1.81 Impact Factor

Publication Stats

1k Citations
355.63 Total Impact Points

Institutions

  • 2006–2014
    • Asan Medical Center
      • • Department of Radiology
      • • Department of Oncology
      Sŏul, Seoul, South Korea
  • 2003–2014
    • University of Ulsan
      • College of Medicine
      Urusan, Ulsan, South Korea
  • 2002–2014
    • Ulsan University Hospital
      Urusan, Ulsan, South Korea
  • 2012
    • Gangneung Asan Hospital
      Sŏul, Seoul, South Korea
    • Hanyang University
      • College of Medicine
      Ansan, Gyeonggi, South Korea
  • 2011
    • University of North Carolina at Chapel Hill
      • Department of Radiology
      Chapel Hill, NC, United States
  • 2008–2010
    • Inje University Paik Hospital
      • Department of Internal Medicine
      Sŏul, Seoul, South Korea
  • 2003–2007
    • Yonsei University Hospital
      Sŏul, Seoul, South Korea
  • 2004
    • Inha University
      • Department of Radiology
      Seoul, Seoul, South Korea