이 달의 영상 : 국소성 위 아밀로이드증

이윤나 ( Yun Nah Lee ),홍수진 ( Su Jin Hong ),김희경 ( Hee Kyung Kim ) 대한소화기학회 2011 대한소화기학회지 Vol.58 No.2

소화기 ; 한국인 자가면역성 간염을 진단하기 위한 Simplified Scoring Criteria의 가치 및 유용성

이윤나 ( Yun Nah Lee ),김영석 ( Young Seok Kim ),김상균 ( Sang Gyune Kim ),임재희 ( Jae Hee Lim ),정승원 ( Soung Won Jeong ),장재영 ( Jae Young Jang ),이세환 ( Se Hwan Lee ),김홍수 ( Hong Soo Kim ),김부성 ( Boo Sung Kim ),김희경 ( 대한내과학회 2011 대한내과학회지 Vol.81 No.3

목적: 자가면역성 간염(AIH)을 진단하기 위한 revised original scoring criteria는 지나치게 번거로워 임상에서의 적용이 쉽지 않았다. 이러한 단점을 보안하기 위해 2008년 Hennes 등 [19]에 의해 simplified scoring criteria가 발표되었다. 이에 저자 등은 이 criteria를 한국인에게 적용하였을 경우, 진단적 가치 및 유용성을 평가하고자 연구를 시행하였다. 방법: Original revised scoring criteria에 의해 AIH이 진단된 22예와 자가면역 간염/원발성담즙 간경변증(autoimmune hepatitis/primary biliary cirrhosis, AIH/PBC) 중복증후군을 진단받은 5예, 그리고 대조군으로 독성간염 50예, 비알코올성 지방간(NAFLD) 18예, 원발성담즙 간경변증(PBC) 11예를 후향적으로 분석하였다. 결과: AIH 중 20명(90.9%)과 AIH/PBC 중복 증후군 5명 모두가 simplified scoring criteria에 의해 AIH로 진단되었다. 그리고 PBC 중 3명인 27.3%에서 새로운 진단기준을 적용하였을 경우 위양성을 보였다. AIH 진단에 대한 simplified scoring criteria의 민감도와 특이도는 각각 90.9%와 96.2%였다. 결론: 한국인에게 simplified scoring criteria는 중복증후군을 포함한 자가면역성 간염을 진단하는 데 유용하게 사용될 수 있을 것으로 생각한다. Background/Aims: The diagnostic criteria for autoimmune hepatitis (AIH) were created and revised by the International Autoimmune Hepatitis Group (IAIHG) in 1999. Simplified scoring criteria based on four clinical components were recently proposed. The aim of this study was to assess the diagnostic value and usefulness of these simplified criteria in Korea. Methods: We applied the simplified scoring criteria to 22 AIH patients diagnosed according to the original revised scoring criteria proposed in 1999. Furthermore, in order to compare the predictive power of these two sets of diagnostic criteria, we included 84 patients with liver diseases [toxic hepatitis (n = 50), nonalcoholic fatty liver disease (n = 18), primary biliary cirrhosis (PBC) (n = 11), and PBC/AIH overlap syndrome (n = 5)] other than AIH. Results: Twenty (90.9%) patients with AIH and five (100%) with PBC/AIH overlap syndrome were diagnosed with AIH according to the simplified scoring criteria. Three (27.3%) patients with PBC were false-positive for AIH according to the simplified scoring criteria. Those patients diagnosed according to the simplified scoring criteria showed an increased frequency of ANA and/or SMA of ≥ 1:80 (p = 0.491) and an increased frequency of serum IgG levels at or above the upper normal limit compared to patients with PBC (p = 0.006). The sensitivity and specificity of the simplified scoring criteria for the diagnosis of AIH were 90.9 and 96.2%, respectively. Conclusions: The simplified scoring criteria offer a reliable and simple method for excluding AIH; however, these criteria may have limitations in the diagnosis of patients with atypical features, especially those with low autoantibody and IgG levels. (Korean J Med 2011;81:340-350)

모호한 담관병변의 진단: 경구 담도 내시경 및 초음파 내시경

이윤나 ( Yun Nah Lee ) 대한췌장담도학회 2020 대한췌담도학회지 Vol.25 No.1

모호한 담관병변은 내시경역행담췌관조영술(endoscopic retrograde cholangiopancreatography, ERCP)을 포함한 하나 이상의 영상 검사에서 관찰되지만, 조직병리학적으로 악성의 근거가 없는 경우로 정의되며, 주로 담관 협착 또는 담관 내충만결손의 형태로 확인된다. 담도 병변의 조직병리학적 확진을 위하여 ERCP 유도하 경유두적 겸자생검 또는 솔세포진 검사가 일차적으로 시행되고 있지만, 이들 검사의 정확도는 만족스럽지 못한 상태이다. 최근 경구 담도 내시경 검사(peroral cholangioscopy, POC)와 내시경 초음파(endoscopic ultrasonography, EUS)는 병변의 내시경 기기의 기술적 발전과 검사 중 조직 검사가 가능하다는 장점을 기반으로 모호한 담관병변의 진단에서의 역할이 점차 확대되고 있다. 담관암 진단에 있어 EUS 검사는 병변의 국소적 침범 정도와 주변 임파선 전이 평가에 매우 유용한 검사이다. 957명의 환자를 대상으로 시행된 20개의 연구를 분석한 meta-analysis에서 악성 담관 협착의 진단에 있어 EUS-FNA의 민감도는 80.0%였으나, 원인 질환 및 협착의 위치에 따른 진단율 차이에 대한 연구는 제한적인 상태이다. POC의 경우 극세경 상부위장관 내시경을 이용한 직접 경구적담도 내시경 검사법(direct POC)과 SpyGlass 시스템(SpyGlass Direct Visualization System, Boston Scientific Corp., Marlborough, MA, USA)이 대표적으로 사용되고 있다. 악성 담관협착에 대한 POC의 육안적 진단은 기존 연구에서 85-100%와 84-91.7%의 높은 민감도와 특이도가 보고된 바 있지만, 아직까지 악·양성 담관 협착의 정확한 내시경적 육안적 진단 기준이 정립되지 않았기 때문에 조직생검없이 담관 협착을 확진하기는 어렵다. POC 유도하 겸자생검은 육안적으로 병변을 직접 관찰하면서 원하는 부위에서 조직 채취가 가능하다는 장점 때문에 모호한 담관병변의 진단에 최근 활발히 사용되고 있다. 모호한 담관 협착에 대한 SpyGlass 시스템 유도하 겸자생검의 진단 민감도와 정확도는 76.5-88.0%와 77.0-90.0%로 보고된 바 있으며, direct POC의 경우 ERCP 유도하 겸자생검으로 악성이 진단되지 않은 32명의 환자를 대상으로 시행한 조직 검사에서 92.3%의 민감도와 93.6%의 진단 정확도를 보여주었다. 하지만 POC의 경우, 원위부 담관 관찰 시 내시경의 위치 유지가 어렵기 때문에 근위부 담관보다 관찰이 어려우며, 담관 협착의 원인이 담관 외부로부터 기원하였을 경우, 조직 검사의 정확도가 유의하게 낮아질 수 있다는 제한점이 있다. 결론적으로 EUS와 POC는 모호한 담관병변의 감별 진단에 유용한 검사법으로, 검사 중 조직 채취가 가능하다는 장점을 가지고 있지만 검사의 정확도를 최대화하기 위해서는 각 검사법의 장단점을 숙지하여 병변의 특징에 따라 적절한 검사법을 선택하는 것이 무엇보다 중요하겠다. Traditionally, biliary lesions have been considered to be indeterminate when a diagnosis cannot be made after basic laboratory work-up, abdominal imaging and endoscopic retrograde cholangiopancreatography (ERCP) with biliary sampling. Although ERCP is a first-line diagnostic modality for indeterminate biliary lesions, the diagnostic yield of ERCP-based tissue sampling is insufficient. In a recent, peroral cholangioscopy (POC)-guided forceps biopsy and endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) are evolving as reliable diagnostic procedures for indeterminate biliary lesions. In previous studies, EUS-FNA was sensitive and highly specific for diagnosing malignancy in biliary strictures. However, EUS-FNA has several limitations as a routine clinical procedure for all biliary strictures. Newly developed POC systems, such as the SpyGlass direct visualization system and direct POC using an ultra-slim endoscope, have led to excessive improvements in technical performance and diagnostic yields for biliary strictures. However, the performance of POC-guided target biopsy for distal bile duct strictures is technically difficult, and this approach has a limited ability to diagnose biliary strictures caused by non-intraductal, extrinsic compressed malignancies, such as a pancreatic cancer. Therefore, a tailored approach using optimized endoscopic modalities that are specific to the characteristics of a given biliary stricture is needed to achieve a high diagnostic yield for indeterminate biliary lesions.

사례보고 : 만성 C형간염 환자에서 페그인터페론 알파 2b 치료 중 동시 발생한 당뇨병성 케톤산증과 자가면역 갑상샘염 1예

이윤나 ( Yun Nah Lee ),정승원 ( Soung Won Jeong ),임재희 ( Jae Hee Lim ),유양선 ( Yang Seon Ryu ),전성란 ( Seong Ran Jeon ),김상균 ( Sang Kyun Kim ),장재영 ( Jae Young Jang ),김영석 ( Young Seok Kim ),김부성 ( Boo Sung Kim ),노미 대한간학회 2010 Clinical and Molecular Hepatology(대한간학회지) Vol.16 No.2

Combined pegylated interferon and ribavirin therapy for chronic hepatitis C infection cause a wide range of side effects, including flu-like syndrome, hematological abnormalities, cardiovascular symptoms, gastrointestinal symptoms, pulmonary dysfunction, depression, and retinopathy. Interferon-alpha has been shown to be related to the development of various autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, autoimmune thyroid disease, and type 1 diabetes mellitus (DM). Type 1 DM and thyroid disease respectively develop in 0.08~2.61% and 10~15% of patients treated with combined interferon-alpha and ribavirin for chronic hepatitis C. The coexistence of type 1 DM and autoimmune thyroiditis was rarely reported. We report a case of a 33-year-old female patient with chronic hepatitis C who simultaneously developed diabetic ketoacidosis and autoimmune thyroiditis after treatment with pegylated interferon-alpha 2b and ribavirin.

COVID-19 기간 대한췌장담도학회의 대면-비대면 학술행사에 대한 만족도 설문 조사

이재민 ( Jae Min Lee ),이희승 ( Hee Seung Lee ),신석표 ( Suk Pyo Shin ),이윤나 ( Yun Nah Lee ),전형구 ( Hyung Ku Chon ),장성일 ( Sung Ill Jang ),이준규 ( Jun Kyu Lee ) 대한췌장담도학회 2021 대한췌담도학회지 Vol.26 No.1

배경/목적: 본 연구는 증증급성호흡기증후군(COVID-19)의 확산에 따라 학술행사의 방식이 직접 참석에서 비대면 온라인 방식으로 점차 변화되는 현재의 경향을 고려하여, 2020년 시행된 학술행사 참석자들의 만족도를 분석한 연구이다. 설문조사를 통해 비대면 온라인 학술대회의 장점과 단점을 분석하고, 이를 토대로 향후 이상적인 학술대회를 준비할 수 있는 자료를 수립하고자 하였다. 방법: 2020년 상반기에 서울에서 개최된 ‘IC-KPBA 2020’ 학술행사의 참석자를 대상으로 18개 문항으로 구성된 설문조사를 시행하였다. 설문조사는 네이버 설문조사의 플랫폼을 이용하여 진행되었다. 결 과 : 비대면 온라인 방식의 학술행사에 대해서 학회 참석자들은 전반적으로 만족 혹은 매우 만족스럽다고 응답하였다. 온라인 참석자들은 네트워크 연결, 화면 및 음향 등의 각각의 항목에서 약 70-85%가 만족 혹은 매우 만족으로 응답하였으며, 직접 참석자들을 대상으로 한 설문에서 방역대책 및 현장의 화면, 음향 시설 등의 각각의 항목에서 약 80-90%가 만족 혹은 매우 만족으로 응답하였다. 향후 학회 참석방식의 선호도 조사에서는 가급적 온라인을 선택하겠다는 답변이 33% 로 가장 높게 나타났다. 결론: 학술행사의 방식이 점차 비대면 온라인으로 변화되는 추세에서 대한췌장담도학회 주관 하에 새로운 방식으로 개최한 국제학술대회에 대한 만족도는 전반적으로 양호-우수한 것으로 확인되었다. Background/Aim: The COVID-19 pandemic has changed the way of traditional conference and meeting. Since social distancing rule was important issue, many conferences across the world were cancelled or postponed indefinitely. In 2020, International Conference of the Korean Pancreatobiliary Association (IC-KPBA) was held as a hybrid online and offline conference. Here, we report the result of a national survey about online and offline medical conference in Korea. Methods: The survey was performed for both online and offline participants after IC-KPBA. The contents of survey included their way to access the hybrid online-offline conference and satisfaction with the conference format. Results: Total of 78 participants answered the survey and there was no technical problem. Most offline participants were satisfied the prevention measures at conference hall as follows; very satisfied-56%; satisfied-34%. The quality of video and audio were generally satisfactory in both conference hall and virtual conference. ‘Live online lectures’ is the most preferred method of lecture delivery and personal computer with LAN network is preferred to access online conference. Eighty seven percent of offline participants and 91% of online participants answered satisfied and very satisfied, respectively. Conclusions: Participants of IC-KPBA 2020 with hybrid online-offline conference showed a high level of satisfaction. Korean J Pancreas Biliary Tract 2021;26(1):49-57

아데포비어 구조요법을 받은 라미부딘 내성 만성 B형 간염 환자에서 간세포암종 발생 빈도

김지현 ( Jihyun Kim ),이세환 ( Sae Hwan Lee ),최강혁 ( Kanghyug Choi ),이윤나 ( Yun Nah Lee ),정승원 ( Soung Won Jeong ),김상균 ( Sang Gyune Kim ),장재영 ( Jae Young Jang ),김영석 ( Young Seok Kim ),김홍수 ( Hong Soo Kim ),김부성 대한간암학회 2013 대한간암학회지 Vol.13 No.2

Background/Aims: Suboptimal virological response to adefovir (ADV) rescue therapy was commonly experienced in patient with lamivudine-resistant chronic hepatitis B. The aim of this study is to compare occurrence of hepatocellular carcinoma (HCC) of patients with adefovir rescue therapy to naive patients with entecavir. Methods: Electronic medical records of 156 patients with lamivudine-resistant chronic hepatitis B who treated with ADV and of 186 naive-patients who received entecavir 0.5 mg, as control group, were reviewed retrospectively. Study subjects were matched using estimated propensity score and 107 matched subjects in each group were analyzed. Cumulative occurrence of HCC was evaluated during antiviral therapy and the association between clinical variables and development of HCC were analyzed using Kaplan-Meyer curve and risk factor for HCC was evaluated with Cox-proportional hazard model. Results: Age, gender, Child-Pugh score, underlying cirrhosis, HBeAg, and HBV DNA level were not different in both groups, except treatment duration with ADV or entecavir (mean 52.6±17.5 vs 46.7±11.4 months, P=0.004). Cumulative virological response rates were 16% and 42% in patient with ADV rescue therapy and 68% and 85% in naive-patients received entecavir at 1 and 3 years (P<0.001), respectively. HCC were diagnosed in 6 of 107 patients with lamivudineresistance and 9 of 107 naive-patients during follow-period and cumulative occurrence rates of HCC was not different between both group (P=0.308). Cumulative occurrence rates of HCC in total 214 subjects were 2.3%, 4.8%, and 9.6% at 1, 3, and 5 years, respectively. Age, underlying cirrhosis, and baseline HBV DNA level were associated with the occurrence of HCC, however gender, HBeAg status, ADV rescue therapy, and cumulative virological response were not correlated in univariate analysis. In multivariate analysis, age (P=0.008) and underlying cirrhosis (P=0.002) were independent risk factors for occurrence of HCC. Conclusions: Long-term ADV rescue therapy in patients with lamivudine-resistant chronic hepatitis B did not increase the occurrence rates of HCC.

소화기 ; 독성간염의 임상적 고찰과 조직소견

임재희 ( Jae Hee Lim ),김영석 ( Young Seok Kim ),이윤나 ( Yun Nah Lee ),김상균 ( Sang Gyune Kim ),정승원 ( Soung Won Jeong ),장재영 ( Jae Young Jang ),이세환 ( Sae Hwan Lee ),김홍수 ( Hong Soo Kim ),김부성 ( Boo Sung Kim ),김희경 대한내과학회 2011 대한내과학회지 Vol.81 No.1

Background/Aims: Although many individual cases of toxic hepatitis have been reported, there are few comprehensive systematic studies and few reports of the pathological findings in toxic hepatitis. We studied the clinical characteristics, pathology, and prognosis of patients with toxic hepatitis. Methods: A retrospective analysis examined the medical records of 184 cases of toxic hepatitis diagnosed from January 2004 to January 2010. Liver biopsies were performed in 62 of these cases. Patients were included in this study it they had a RUCAM score ≥4. Results: The incidence was higher in women (n=125) than in men (n=59). The mean age of the patients was 45.9±14.4 years.The most common symptom was jaundice (56/184; 30.4%). The causative agents of the disease included herbal medications (43.5%), traditional therapeutic preparations (33.7%), and prescribed medications (21.7%). The pathological findings of toxichepatitis included necrosis (n=62), cholestasis (n=43), steatosis (n=23), eosinophilic infiltrations (n=22), and ballooning degeneration (n=20). The patients with cholestasis and necrosis were hospitalized longer and showed delayed recovery. The only prognostic factor associated with the hospitalization and recovery periods was the serum total bilirubin at the time of admission (p<0.001). Conclusions: The common pathological findings of toxic hepatitis were necrosis and cholestasis, although these are not specific to toxic hepatitis. Only the total bilirubin at the time of admission was significantly associated with the duration of hospitalization and recovery. (Korean J Med 2011;81:53-63)

절제 불가능한 원발성 간세포암종에 대하여 DC beads(r)를 사용한 반복적인 경동맥 화학색전술 후 간절제술을 시행한 1예

송정엽 ( Jeong-yeop Song ),김영석 ( Young Seok Kim ),이재명 ( Jae Myeong Lee ),진수지 ( Soo Ji Jin ),최규성 ( Kyu Sung Choi,),이윤나 ( Yun Nah Lee ),김상균 ( Sang Gyune Kim ),정승원 ( Sung Won Jeong ),장재영 ( Jae Young Jang ) 대한간암학회 2013 대한간암학회지 Vol.13 No.1

In patients with unresectable hepatocellular carcinoma (HCC) and no anti-cancer treatment, the prognosis is quite poor. But in some cases, repeated sessions of transcatheter arterial chemoembolization (TACE) reduce the tumor size even to resectable, and post-TACE resection may prolong the survival time. We present a case of 50-year-old HBV carrier woman with abdominal distension. The diagnosis was huge HCC with intrahepatic metastasis. Repeated intra-arterial injections of adriamycin mixed lipiodol or DC beads(R) (100-300/300-500/500-700 μm, ⓒBIOCOMPATIBLES UK LTD) were instituted through ten sessions for 13 months. The tumor size became reduced with a partial response after 10th TACE and post-TACE resection was performed. No visible HCCs and decreased tumor markers were noted on the examinations 3 months after the resection.

헬리코박터 파이로리 치료 실패 후 레보플록사신을 이용한 3차 구제요법의 기간에 따른 제균율

노형민 ( Hyung Min Noh ),홍수진 ( Su Jin Hong ),한재필 ( Jae Pil Han ),박경우 ( Kyung Woo Park ),이윤나 ( Yun Nah Lee ),이태희 ( Tae Hee Lee ),고봉민 ( Bong Min Ko ),이준성 ( Joon Seong Lee ),이문성 ( Moon Sung Lee ) 대한소화기학회 2016 대한소화기학회지 Vol.68 No.5

Background/Aims: This study evaluated the eradication rate of levofloxacin-containing rescue therapy by treatment duration in patients in whom previous first- and second-line treatment failed. Methods: Fifty-five patients with persistent Helicobacter pylori infection after first-line therapy and second-line therapy were studied in a single referral academic center. We compared the eradication rates by the treatment duration of third-line therapy. Results: Of 55 patients, 12 (21.8%) received rescue therapy for seven days, 24 (43.6%) received rescue therapy for 10 days, and 19 (34.5%) received rescue therapy for 14 days. The eradication rates of therapy with levofloxacin were 65.5% in the 55 enrolled patients and 73.5% in the 49 patients who underwent follow-up testing. In cases where follow-up testing was performed, the eradication rate of 7-day therapy was 58.3%, of 10-day 68.2%, and of 14-day therapy 93.3%. Eradication rate of 14-day therapy was higher than 7-day (p=0.06) and 10-day (p=0.108), but chance could not be ruled out in the difference among groups. Conclusions: This study showed somewhat increasing of H. pylori eradication rate by extending the duration of levofloxacin-containing rescue therapy to 14 days. (Korean J Gastroenterol 2016;68:260-264)

위장관 ; 미분화 조기위암에서 내시경 점막하박리술의 치료 성적

최문한 ( Moon Han Choi ),홍수진 ( Su Jin Hong ),한재필 ( Jae Pil Han ),송정엽 ( Jeong Yeop Song ),김대용 ( Dae Yong Kim ),서성우 ( Sung Woo Seo ),하지수 ( Ji Su Ha ),이윤나 ( Yun Nah Lee ),고봉민 ( Bong Min Ko ),이문성 ( Moon Sung 대한소화기학회 2013 대한소화기학회지 Vol.61 No.4

목적: 내시경 점막하박리술은 조기위암의 표준 치료로 받아들여지고 있다. 하지만, 미분화 조기위암에 대한 내시경 점막하박리술의 적응증은 아직 논란이 있다. 이번 연구에서는 확대 적응증에 의한 미분화 조기위암에서 내시경 점막하박리술의 치료 성적에 대해 파악하고자 하였다. 대상 및 방법: 순천향대학교 의과대학 부천병원에서 미분화 조기위암 환자 81명을 대상으로 82병변에 대해 내시경 점막 하박리술을 시행하였다. 치료 성적에 대해 절제 방법(일괄 절제, 분할 절제), 완전 절제율, 합병증, 재발률에 대해 조사하였다. 결과: 일괄 절제율과 완전 절제율은 각각 87.8% (72/82)과 80.5% (66/82)였다. 반지세포암종에서 저분화 선암종과 반지 세포를 동반한 저분화 선암종에 비해 높은 완전 절제율을 보였으나, 통계학적 의미는 없었다(89.3% vs. 75.0%, 76.7%; p=0.347). 저분화 선암종, 반지세포암종, 반지세포를 동반한 저분화 선암종에서 측면절제면 양성이 확인된 경우는 각각 12.5%, 3.6%, 13.3%였다(p=0.395). 기저절제면 양성이 확인된 경우는 각각 12.5%, 3.6%, 10.0%였다(p=0.485). 평균 37.4 개월의 추적기간 동안 재발률은 3.0%였다. 결론: 확대 적응증에 의한 미분화 조기위암에서의 내시경 점막하박리술은 유용한 치료가 될 것으로 생각되나, 장기적이고 대규모의 연구가 필요하겠다. Background/Aims: Endoscopic submucosal dissection (ESD) has been accepted as a standard treatment of early gastric cancer (EGC). However, the indication of ESD in undifferentiated-type EGC was controversial. The aim of this study was to evaluate the therapeutic outcomes of ESD in undifferentiated-type EGC according to expanded indication. Methods: At Soonchunhyang University Bucheon Hospital, a total of 82 lesions in 81 patients with undifferentiated-type EGC were treated with ESD. The therapeutic outcomes of ESD were evaluated by resection method (en bloc resection; piecemeal resection), histologic curative resection, complications and recurrence rates after ESD. Results: The rate on en bloc resection and complete resection rate were 87.8% (72/82) and 80.5% (66/82), respectively. In signet ring cell carcinoma, the complete resection rate was higher than those in poorly differentiated adenocarcinoma and poorly differentiated adenocarcinoma with signet ring cell features, but there was no statistical significance (89.3% vs. 75.0%, 76.7%; p=0.347). The lateral margin positivity rate in poorly differentiated adenocarcinoma, signet ring cell carcinoma and poorly differentiated adenocarcinoma with signet ring cell features were 12.5%, 3.6% and 13.3%, respectively (p=0.395). The vertical margin positivity rate were 12.5%, 3.6% and 10.0%, respectively (p=0.485). The overall recurrence rate was 3.0% during a mean follow-up period of 37.4 months. Conclusions: ESD may be considered as a feasible treatment for undifferentiated-type EGC according to expanded indication. The therapeutic outcome of ESD in undifferentiated-type EGC is likely to be favorable, though further longer follow-up studies are needed. (Korean J Gastroenterol 2013;61:196-202)