• Journal of International Society for Simulation Surgery
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• 제1권1호
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• pp.37-40
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• 2014

Purpose For living donor liver transplantation, liver segmentation is difficult due to the variability of its shape across patients and similarity of the density of neighbor organs such as heart, stomach, kidney, and spleen. In this paper, we propose an automatic segmentation of the liver using multi-planar anatomy and deformable surface model in portal phase of abdominal contrast-enhanced CT images. Method Our method is composed of four main steps. First, the optimal liver volume is extracted by positional information of pelvis and rib and by separating lungs and heart from CT images. Second, anisotropic diffusing filtering and adaptive thresholding are used to segment the initial liver volume. Third, morphological opening and connected component labeling are applied to multiple planes for removing neighbor organs. Finally, deformable surface model and probability summation map are performed to refine a posterior liver surface and missing left robe in previous step. Results All experimental datasets were acquired on ten living donors using a SIEMENS CT system. Each image had a matrix size of $512{\times}512$ pixels with in-plane resolutions ranging from 0.54 to 0.70 mm. The slice spacing was 2.0 mm and the number of images per scan ranged from 136 to 229. For accuracy evaluation, the average symmetric surface distance (ASD) and the volume overlap error (VE) between automatic segmentation and manual segmentation by two radiologists are calculated. The ASD was $0.26{\pm}0.12mm$ for manual1 versus automatic and $0.24{\pm}0.09mm$ for manual2 versus automatic while that of inter-radiologists was $0.23{\pm}0.05mm$. The VE was $0.86{\pm}0.45%$ for manual1 versus automatic and $0.73{\pm}0.33%$ for manaual2 versus automatic while that of inter-radiologist was $0.76{\pm}0.21%$. Conclusion Our method can be used for the liver volumetry for the pre-surgery planning of living donor liver transplantation.

• 대한이식학회지
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• 제32권4호
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• pp.92-103
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• 2018

Background: Currently, trimethoprim-sulfamethoxazole is used for Pneumocystis jirovecii pneumonia (PJP) prophylaxis, but it is associated with frequent adverse effects. This study evaluated the efficacy and safety of the current protocol and proposes an individualized risk-based prophylaxis protocol. Methods: The PJP incidence and risk factors during the first 6 months (early PJP) and afterwards (late PJP) was assessed in renal transplant recipients with (prophylaxis group) and without (no-prophylaxis group) 6-month PJP prophylaxis. Results: In 578 patients, there were 39 cases of PJP during a median follow-up of 51 months. Renal adverse events were encountered frequently during trimethoprim-sulfamethoxazole prophylaxis, leading to premature discontinuation. Patients without the prophylaxis had a significantly higher incidence of early PJP (n=27, 6.6%) compared to patients with the prophylaxis (n=0). The incidence of late PJP was 2.2%, without between-group differences. The factors associated with early PJP were preoperative desensitization and acute rejection within 1 month, whereas late PJP was associated with age, deceased donor transplant, and acute rejection requiring antithymocyte globulin treatment. Conclusions: Based on the simulation results of several risk-based scenarios, the authors recommend universal prophylaxis up to 6 months post-transplant and extended selective prophylaxis in patients aged ${\geq}57$ years and those with a transplant from deceased donors.

• 대한이식학회지
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• 제31권4호
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• pp.157-169
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• 2017

Regulatory T cells (Treg) naturally rein in immune attacks, and they can inhibit rejection of transplanted organs and even reverse the progression of autoimmune diseases in mice. The initial safety trials of Treg against graft-versus-host disease (GVHD) provided evidence that the adoptive transfer of Treg is safe and capable of limiting disease progression. Supported by such evidence, numerous clinical trials have been actively investigating the efficacy of Treg targeting autoimmune diseases, type I diabetes, and organ transplant rejection, including kidney and liver. The limited quantity of Treg cells harvested from peripheral blood and subsequent in vitro culture have posed a great challenge to large-scale clinical application of Treg; nevertheless, the concept of CAR (chimeric antigen receptor)-Treg has emerged as a potential resolution to the problem. Recently, two CAR-T therapies, tisagenlecleucel and axicabtagene ciloleucel, were approved by the US FDA for the treatment of refractory or recurrent acute lymhoblastic leukemia. This approval could serve as a guideline for the production protocols for other genetically engineered T cells for clinical use as well. The phase I and II clinical trials of these agents has demonstrated that genetically engineered and antigen-targeting T cells are safe and efficacious in humans. In conclusion, both the promising results of Treg cell therapy from the clinical studies and the recent FDA approval of CAR-T therapies are paving the way for CAR-Treg therapy in clinical use.

• 대한이식학회지
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• 제31권4호
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• pp.170-176
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• 2017

We need to establish an informative guideline to increase inter-institutional and inter-observer reproducibility of renal transplant diagnosis, and to improve the diagnostic ability of pathologists in Korea. A first nation-wide survey for renal transplant pathology was conducted by Renal Pathology Study Group of the Korean Society of Pathologists in 2016, to provide the continued excellence in the transplantation pathology laboratory, and to improve the diagnostic ability for the best treatment of transplant patients. This survey revealed the significant variations in scale, work load and biopsy indications for the renal transplant pathology in various institutions in Korea. The Banff classification were used by all institutions for the diagnosis of renal transplant pathology, but different formats were used: most institutions (70%) used the "2013 Banff classification" while the others were using "2007 Banff classification" (20%) or even older formats. In daily diagnostic practice of the renal allografts, difficulties that pathologists encounter were quite diverse due to different environments they work in. Most respondents agreed that standardized diagnostic practice guidelines, regular education on renal transplant pathology and convenient ways of consultation are further needed. We are currently working toward the enhancement of the expertise of renal pathologists and to increase inter-institutional and inter-observer reproducibility by 1) development of a set of virtual slides of renal allograft biopsies for the training, 2) validation and gathering expert's consensus on the core variables of rejection diagnosis by using virtual slides, and 3) continued education by the developed virtual slide atlas.

• Journal of Chest Surgery
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• 제30권6호
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• pp.573-579
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• 1997

지난 30년동안 장기이식분야의 괄목할만한 발전과 더불어 국내에서도 신장, 간 등은 물론 심장이식도 활 발히 이루어지고 있다. 그러나 폐 이식만은 많은 제약으로 인하여 답보상태를 면하지 못하고 있으며 그중에 서도 장기공여자의 부족과 상대적으로 허혈-재관류손상에 예민한 폐 자체의 보존시간의 문제가 가장 먼저 해결해야 할 과제로 여겨지고 있다. 일반적으로 폐는 허혈에 견딜수 있는 시간이 4-6시간으로 알려져 있으 며 많은 연구자들이 더 좋은 폐보존방법을 연구하고 평가하기 위한 실험모델을 개발하여 왔다. 그러나 많 은 실험모델의 등장으로 같은 실험도 서로 상반되는 결과를 낳고 있으며 각각의 모델이 가진 단점들로 인 하여 실험모형의 표준화와 결과분석의 기준을 정하는데 있어 완벽한 모델은 정립된 것이 없는 상태이다. 폐 보존후 기능에 영향을 미칠 수 있는 요인들 즉 허혈성 보존기간, 보존 온도, 폐관류액치 구성성분 등 을 분석하는데는 비교적 간단하고, 경비가 적게 들며 실험결과의 신뢰도가 높은 새로운 모형의 개발이 요 구 되었다. 이에 서울대학교병원 흉부외과에서는 빠르게 변화하는 폐 보존 방법의 실험 및 한국에서는 거 \ulcorner이루어지지 않고 있는 폐 보존 방법에 대한 통계 자료를 확보하여 폐 이식 수술에 이를 적용하고자, 연 구노력 끝에 토끼 폐장으로 상기 목적에 적합한 폐장 분리관류 모형을 완성하였다.

• 한국임상수의학회지
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• 제28권1호
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• pp.57-62
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• 2011

The shortage of transplantable kidneys has many efforts to regenerate bioartificial kidneys using transgenic animals and diverse kinds of scaffolds which are important tools for cell seeding. However, there are many limitations for clinical applications so far. Recently, decellularized bioscaffolds using animal organs come into spotlight because of its many superior advantages. In current study, we produced decellularized kidney bioscaffolds of pig which is an attractive animal as a clinical model for human. We decellularized pig kidneys with 1% SDS detergent solution using peristaltic pump systems for 12h. After decellularization process, the kidney bioscaffolds preserved intact 3D morphology including glomerular structure and almost DNA from pig was entirely removed. In addition, this process could preserve micro vascular network which is necessary for cell survival. Although, additional studies for recellularization and transplantation should be required, the decellular vascularized kidney bioscaffolds might have many potentials for kidney regeneration.

• Journal of Yeungnam Medical Science
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• 제32권2호
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• pp.155-158
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• 2015

Lymphangioma is a congenital abnormality of the lymphatic system detected primarily in early childhood. There are rare reports of mediastinal lymphangioma in older adults. We hereby report on a 66-year-old female patient who underwent kidney transplantation 20 years previously and who developed pathologically confirmed solitary mediastinal lymphangioma 1 year ago. Chest radiography showed a mediastinal nodule, which was not observed 2 year previously, therefore she was referred to the pulmonary division. She had no symptoms, and chest computed tomography demonstrated a 25-mm, well-defined, low-density nodule located at the anterior mediastinum. The size of the nodule had increased from 25 mm to 34 mm 1 year later, and it was completely resected via video-assisted thoracic surgery. The histological diagnosis was cystic lymphangioma. Therefore, we recommend that clinicians consider cystic lymphangioma as a possible diagnosis even in older patients with a mediastinal cystic mass that shows progressive enlargement.

• Archives of Plastic Surgery
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• 제41권5호
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• pp.505-512
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• 2014

Background Laryngeal allotransplantation (LA) is a technique involving transplantation of a deceased donor's larynx into a recipient, and it may be substituted for conventional laryngeal reconstruction. There are widely different views on LA, as the recipient is administered continuous, potentially life-threatening, immunosuppressive therapy for a functional or aesthetic result, which is not directly related to life extension. The purpose of this study was to analyze the difference in risk acceptance and expectations of LA between four population groups. Methods A survey was performed to examine patients' risk acceptance and expectations of LA. The survey included 287 subjects in total (general public, n=100; kidney transplant recipients, n=53; post-laryngectomy patients, n=34; doctors, n=100), using a Korean translated version of the louisville instrument for transplantation (LIFT) questionnaire. Results All four groups responded differently at various levels of their perception in risk acceptance and expectations. The kidney transplant recipients reported the highest risk acceptance and expectations, and the doctor group the lowest. Conclusions This study examined the disparate perception between specific population groups of the risks and benefits of using LA for the promotion of the quality of life. By addressing the information gaps about LA in the different populations that have been highlighted from this survey, we suggest that LA can become a more viable alternative to classical surgery with resultant improved quality of life for patients.

• 한국방사선학회논문지
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• 제11권3호
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• pp.153-159
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• 2017

만성 콩팥질환은 조기에 발견할 경우 치료가 가능하지만 질병이 진행될수록 회복이 불가능해지며 결국 이식이나 투석 등 신대체요법을 사용하여야 한다. 초음파 검사는 콩팥암, 염증성질환, 결절성 질환, 만성콩팥질환 등을 진단하는 검사 방법으로 콩팥의 크기, 내부 에코의 특성 등의 정보를 이용하여 염증의 정도에 대한 정보를 확인하기 위해서 사용된다. 현재 임상에서 질병의 정도는 사구체 여과율의 수치를 사용한다. 하지만 초음파에서도 염증과 질병의 정도 변화는 관찰이 가능하다. 본 연구에서는 초음파 영상을 컴퓨터 알고리즘을 이용하여 콩팥의 질병이 진행됨에 따라 변화하는 명도와 크기, 겉질과 속질의 불분명해지는 것을 수치로 정량화하여 임상에서 사용되고 있는 사구체여과율과 비교하여 영상이 일치하는지 실험하였다. 전체 영상 105증례에서 정상 콩팥 영상 35증례, 초기 콩팥질환 영상 35증례, 말기 콩팥질환 영상 35증례로 실험하였다. 영상의 겉질의 명도를 구하고 겉질과 신동 부분의 명도차이를 기울기로 구했고, 초음파 특성상 매끄럽지 못한 부분의 그래프는 함수 regrass를 이용하였다. 크기감소는 원본 데이터의 값으로 구하였다. 분석한 결과 영상은 영상의학과 판독과 일치하였고, 사구체 여과율과 비례하였다. 이는 향후 알고리즘 연구가 계속 진행된다면 초음파 영상의 질병에 대한 적용이 가능할 것으로 사료된다.

• Childhood Kidney Diseases
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• 제4권1호
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• pp.84-91
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• 2000

목 적 : 신이식을 받은 환아들의 키 성장에 영향을 미치는 인자를 찾아내어, 신이식 후 성장의 향상에 기여하고자 본 연구를 시행하였다. 방 법 :서울대학교 병원에서 신이식을 받고 이식 당시와 이후 3년간 키에 대한 정보를 얻을 수 있었던 56명의 환아를 대상으로 하여 이식 당시와 이후 6개월, 1년, 2년, 3년 후의 Z-score를 구하였다. 성별, 이식 당시의 나이, 이식 후 사용된 스테로이드의 평균누적 용량, 이식 전 성장 지연 정도, 공여자의 특성, 이식 전 투석여부와 이식신의 기능이 이들 Z-score와 delta Z에 미치는 영향을 알아보았다. 결 과 : 신이식 당시의 Z-score는 연령이 어릴수록 유의하게 높았다. 신이식 당시의 Z-score가 낮을수록 이식 후 Z-score의 상승폭이 더 컸으나(P<0.01) 절대값은 더 낮았다(P<0.001). 신이식 후 Z-score의 분석에서 편상관관계를 구해 보면 연령이 어릴수록, 이식 후 스테로이드 투여량이 적을수록 이식 1년 후의 Z-score와 delta Z가 유의하게 높았다(P<0.05). 이식 후 creatinine이 상승되어 있는 군이 정상인 군에 비하여 이식 6개월, 1년 후의 delta Z가 유의하게 낮았다(P<0.05). 투석 여부, 성별이나 공여자의 종류에 따른 Z-score의 차이는 뚜렷하지 않았다. 결 론 :말기 신부전 환아에서 신이식 당시의 나이가 어릴수록, 신이식 후 투여한 스테로이드의 용량이 낮을 수록 신이식 후 키 성장회복이 좋았다. 신이식 당시의 성장지연이 심할 수록 신이식 후 성장회복의 폭은 높았으나 성장지연은 계속 심한 상태로 남아있었다. 이식신의 기능이 잘 유지될수록 성장 속도가 잘 유지되었다.