• Journal of the Korean Society of Radiology
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• v.84 no.4
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• pp.923-933
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• 2023

Purpose To evaluate the sensitivity of corticomedullary-phase imaging for detecting urinary stones in patients with renal colic who visited the emergency department. Materials and Methods This retrospective study included 253 patients with suspected renal colic from two tertiary hospitals in South Korea, who visited the emergency department and underwent CT urography. Two radiologists blinded to the clinical history independently reviewed the corticomedullary-phase images. The sensitivity for identifying urinary stones were evaluated for each reviewer. After the initial evaluation, the images were re-evaluated based on patient history. The sensitivity of re-evaluation were recorded. Results Of 253 patients, 150 (59%) had urinary stones. Among them, significant stones were observed in 138 patients (92%), and obstructive changes on CT in 124 patients (82.7%). For identifying significant urinary stones, the sensitivity was 98.6% (136/138) for both the reviewers. For identifying significant urinary stones with urinary obstruction, the sensitivity was 99.2% (123/124) for reviewer 1, and 100% (124/124) for reviewer 2. The sensitivity for identifying significant stones increased from 98.6% to 100% for reviewer 1, and from 98.6% to 99.3% for reviewer 2 in the re-evaluation session. Conclusion The corticomedullary-phase CT urography was sensitive for diagnosing urolithiasis in patients with acute renal colic who visited the emergency department.

• Journal of the Korean Society of Radiology
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• v.83 no.3
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• pp.608-619
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• 2022

Purpose This study aimed to evaluate the natural growth of subepithelial tumors of the small bowel detected on CT. Materials and Methods Consecutive patients who were suspected of having subepithelial tumors of the small bowel between January 2005 and December 2020 were reviewed. Eligible patients with suspected small (< 30 mm) subepithelial tumors on at least two CT evaluations were included in the analysis. The patients' data on demographic characteristics, tumoral characteristics, and tumoral size changes during the follow-up were collected. Results This study included 64 patients with suspected small subepithelial tumors (n = 64) of the small bowel. After a median follow-up of 15.8 months, the diameter and volume growth rates were 0.02 mm/month and 1.5 mm³/month, respectively. A significant correlation was observed between the initial size and the growth rate of the small bowel subepithelial tumors. The group of large-sized tumors (initial diameter ≥ 10 mm) tended to show lobulated contours, heterogeneous enhancement, and necrotic changes more frequently than the group of small-sized tumors (initial diameter < 10 mm). Conclusion Small bowel subepithelial tumors measuring less than 10 mm grew more slowly than those measuring 10-30 mm.

• Journal of the Korean Society of Radiology
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• v.82 no.3
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• pp.613-623
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• 2021

Purpose To evaluate the MRI findings and clinical factors that are characteristic of patients who ultimately undergo surgery for medial epicondylitis. Materials and Methods Fifty-two consecutive patients who were diagnosed with medial epicondylitis and underwent an elbow MRI between March 2010 and December 2018 were included in this retrospective study. The patients' demographic information, clinical data, and MRI findings were evaluated. All variables were compared between the conservative treatment and surgical treatment groups. Logistic regression analyses were conducted to identify which factors were associated with surgical treatment. Results Common flexor tear (CFT) tear size showed a statistically significant difference in both the transverse and longitudinal planes (p < 0.001, p = 0.013). The CFT abnormality grade significantly differed in both the transverse and longitudinal planes (p = 0.022, p = 0.003). A significant difference was also found in the medial collateral ligament abnormality (p = 0.025). Logistic regression analyses showed that only the transverse diameter of the CFT tear size (odds ratio: 1.864; 95% confidence interval: 1.264-2.750) was correlated with surgical treatment. Conclusion Of patients diagnosed with medial epicondylitis, patients with a larger transverse CFT tear size tend to undergo surgical treatment ultimately.

• Progress in Medical Physics
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• v.12 no.1
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• pp.51-58
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• 2001

Synchrotron radiation (SR) has several advantages over convetional x-rays, including its phase, collimation, and high flux. A synchrotron radiation beamline 5C1 at Pohang Light Source (PLS) was recently built for imaging applications. We have shown that a SR imaging system is useful in imaging microscopic structures. SR with broad-band energy spectrum were adjusted to an object by Si wafers and their energy were approximately ranging from 6 keV to 30 keV. SR were passed through an object and finally transformed into visible lights by CdWO$_4$ scintillator screen. The visible lights which were reflected at an angle of 90 degrees by gold plated mirror were detected by a CCD camera and the image data were acquired using image acquisition system. A high-resolution phantom, capacitor, adult tooth, child tooth, cancerous breast tissue, and mouse lumbar vertebra were imaged with SR imaging system. The Objects were rotated within the field of view of the CCD detector, and their projection image data were obtained at 250 steps over 180 degrees rotation. Image reconstructions were carried out in a PC by using IDLTM(Research systems, Inc., US) program. The spatial resolution of the images acquired by the SR imaging system was measured with a high-resolution chart manufactured for several micrometer resolution. The specimens were also imaged with conventional x-ray radiography system to compare the image quality of radiography obtained with the SR imaging system. The results showed more structural details and high contrast images with SR imaging system than conventional x-ray radiography system. The SR imaging system may have a potential for imaging in biological researches, material applications, and clinical radiography.

• 전기의세계
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• v.53 no.4
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• pp.59-61
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• 2004

컴퓨터 기술의 발전과 데이터 압축 및 전송 기술의 발달로 인하여, 인터넷을 통하여 실시간으로 전송된 음성, 비디오, 생체 신호, 문자, 처방, 의료 영상 등으로 이루어진 멀티미디어 의료 정보가 임상 진료, 의학 연구 및 교육에 활용되고 있다.(중략)

• Proceedings of the Korean Magnestics Society Conference
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• 2017.05a
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• pp.193-194
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• 2017

• Journal of the Korean Society of Radiology
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• v.82 no.6
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• pp.1570-1574
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• 2021

Post-partum galactocele is a common benign disease among breastfeeding women, whereas retromammary and peri-implant galactocele are relatively rare conditions. Herein, a 34-year-old, 1 month-postpartum female, who had augmentation mammoplasty and a 1-month history of breast pump use, presented with left breast enlargement for 2 weeks. An initial left breast US revealed hyperechoic peri-implant fluid collection. Additional US-guided fine needle aspiration was done using a 21G-needle, draining the milk component in the process, and cytologic results revealed numerous crystals, suggestive of galactocele. Various diseases, especially breast implant-associated anaplastic large cell lymphoma, can cause peri-implant fluid collection in an augmented breast. Thus, correlating imaging features with clinical information and cytologic analysis plays an important role in appropriate management.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.368-370
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• 2013

본 논문에서는 복부 초음파 영상에서 복부 근육을 추출하고 추출된 근육 영역에서 지방을 분석하는 방법을 제안한다. 복부 초음파 영상에서 밝은 명암도를 가지는 근막 영역과 어두운 명암도를 가지는 근육 영역의 명암 대비를 강조하기 위해서 앤드 인 탐색 스트레칭 방법과 Multiple 연산을 적용한다. 평균 명암도와 명암 대비가 강조된 복부 초음파 영상에서 수직 방향의 명암도가 200이상인 픽셀들은 퍼지 이진화 기법을 적용하여 이진화한다. 이진화된 영상에서 외복사근 상단선을 추출한 후, 퍼지 이진화 기법이 적용된 영상과 합성한다. 합성된 영상에서 최종 근막 영역을 추출한다. 추출된 각각의 복부 근육 영역에 ART2 알고리즘을 적용하여 복부 근육 영역을 양자화한다. 양자화된 복부 근육 내의 영역을 분석하여 최종 지방 영역을 추출한다. 제안된 복부 근육 추출 및 지방 분석 방법을 실제 복부 초음파 영상을 대상으로 실험한 결과, 추출된 복부 근육 영역에 ART2 알고리즘 기반 양자화 기법을 적용하여 지방을 추출하는 것이 복부비만을 분석하는데 도움이 되는 것을 영상 의학과 전문의를 통해 확인하였다.

• Journal of the Korean Society of Radiology
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• v.81 no.2
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• pp.290-301
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• 2020

The surgical technique of mitral valvuloplasty or transcatheter mitral valve (MV) replacement has been developed recently. Surgeons and interventionists require detailed anatomical information on the MV for the purpose of treatment planning. In this review, we discussed the anatomic features of the MV on CT and the method of evaluating the MV for treatment planning, as well as its preservation, for interventional procedures.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.935-938
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• 2000

본 논문은 광학 현미경을 컴퓨터 상에서 구현한 소프트웨어 시스템인 Medieye 시스템에 가장 큰 문제점인 대용량의 영상 데이터를 압축하는 기법을 제안하고, Medieye 시스템에 대하여 기술한다. 현재 구현된 Medieye 시스템은 환자의 조직 샘플에 대한 고해상도 디지털 영상을 인터넷 상에서 제공하고 있으며, 궁극적으로는 의료 기관 및 의학 연구 기관의 슬라이드로 꽉 찬 캐비넷을 디지털 저장시스템으로 대체하기 위한 클라이언트 서버 구조 기반의 소프트웨어 시스템이다. Medieye 시스템은 클라이언트 프로그램, 네트워크 서버, 데이터 서버 3 부분으로 구성되었고, 이들은 정해진 통신 규약에 따라 메시지를 서로 주고받음으로써 각 부분이 상호 독립적이다 이 시스템에 적용할 영상압축 기법은 블록 기반의 웨이블릿 변환을 이용한 영상 압축이다. 입력 영상 신호를 여러 개의 부밴드 영상으로 분해하고 각 부밴드 영상에 대하여 독립적으로 다시 작은 블록으로 나누어 각 부밴드의 특성에 맞도록 영상을 압축하는 알고리즘을 제안하였다. 이 기법은 제로 트리와 비슷한 성능을 보이면서도 구조가 비교적 간단하여 계산적인 면과 수행 속도 면에서 우수한 성능을 보여 준다.