무선전력전송 시스템의 최적 코어형상 설계를 위한 인공지능 기법 비교 및 분석

문우현(Woo-Hyeon Moon),김윤수(Yun-Su Kim) 대한전기학회 2020 대한전기학회 학술대회 논문집 Vol.2020 No.10

단축 자기공명영상검사를 이용한 유방암 검진

이수현,문우경 대한영상의학회 2019 대한영상의학회지 Vol.80 No.1

Magnetic resonance imaging (MRI) is the most sensitive modality used for breast cancer screening, and is known to detect biologically significant cancers and few interval cancers. Application of standard breast MRI examination is not economical for screening due to the high costs associated with long interpretation and reading times. However, abbreviated breast MRI can reduce time and cost while maintaining diagnostic accuracy, and improve cost-effectiveness in breast cancer screening. A multi-center clinical trial on breast cancer screening using abbreviated breast MRI in high-risk women in Korea is being conducted. Another multicenter clinical trial has been conducted in the USA and Europe to investigate the efficacy of abbreviated breast MRI in women with average to intermediate cancer risk. Furthermore, when performed simultaneously with ultrafast MRI, the accuracy of abbreviated breast MRI can be enhanced. However, since abbreviated breast MRI uses contrast agents, it is important to consider the possibility of residual gadolinium in the body. 유방 자기공명영상(magnetic resonance imaging; 이하 MRI)은 유방촬영술이나 초음파에 비해 민감도가 높고 생물학적으로 더 중요한 암을 발견하며 간격암(interval cancer) 발생이 적다. 표준 유방 MRI는 검사 시간과 판독 시간이 길어 높은 검사 비용이 발생하여 검진에 적용하기에는 비용-효과적이지 않다. 단축 유방 MRI는 진단 정확도는 유지하면서 시간과 비용을 줄여 유방 MRI 검진의 비용-효과를 높일 수 있다. 우리나라에서는 고위험군 여성에서 단축 유방 MRI를 이용한 검진에 대한 다기관 임상연구가 진행되고 있으며, 미국과 유럽에서 함께 진행되고 있는 다기관 임상연구는 중등도 또는 평균 위험도의 여성에서 단축 유방 MRI 검진의 유용성을 평가한다. 단축 유방 MRI 시행 시 초고속 MRI 기법을 함께 사용하면 검사 시간을 늘리지 않으면서 병변의 감별진단 정확도를 더욱 높일 수 있다. 하지만, 평균 위험도의 여성에서 단축 유방 MRI 검진은 조영제를 반복 사용하므로 가돌리늄의 체내 잔류 가능성을 염두에 두어야 한다.

Ultrasound Elastography in Evaluation of Breast Lesions: Phantom and Clinical Studies

이수현,조나리야,문우경,이정찬,장정민 대한초음파의학회 2013 ULTRASONOGRAPHY Vol.32 No.1

Purpose: The purpose of this study was to correlate the tissue stiffness measured using ultrasound elastography with directly measured tissue stiffness. Materials and Methods: A phantom model consisting of five materials with different levels of stiffness was constructed. Forty one patients who were scheduled to undergo a vacuum-assisted biopsy for breast lesions were prospectively recruited for this study. Elasticity (E) score and strain index obtained with strain imaging were correlated with the directly measured stiffness value of phantom and core specimen. Results: The E score and strain index of each phantom material showed a high level of correlation with the measured stiffness (E score: r = 0.985, P = 0.002; strain index: r = 0.964, P = 0.008). The E score and strain index of the breast lesions showed a low level of correlation with the reference standard (E score: r = 0.261, P =0.100, strain index: r = 0.397, P = 0.014). The mean value of the E score was significantly greater in malignant (3.6) than in benign lesions (2.4) (P = 0.004). Conclusion: Stiffness of the phantom materials assessed by US strain imaging was well correlated with the reference standard of direct measurement. The E score can be used as a non-invasive diagnostic tool in differentiation of benign and malignant breast lesions.

Practice guideline for the performance of breast ultrasound elastography

이수현,장정민,조나리야,구혜령,이안,김승자,육지현,손은주,최선형,국신호,정진,차은숙,박정선,정해경,고경희,최혜영,류은비,문우경,한국유방초음파연구회 대한초음파의학회 2014 ULTRASONOGRAPHY Vol.33 No.1

Ultrasound (US) elastography is a valuable imaging technique for tissue characterization. Two main types of elastography, strain and shear-wave, are commonly used to image breast tissue. The use of elastography is expected to increase, particularly with the increased use of US for breast screening. Recently, the US elastographic features of breast masses have been incorporated into the 2nd edition of the Breast Imaging Reporting and Data System (BI-RADS) US lexicon as associated findings. This review suggests practical guidelines for breast US elastography in consensus with the Korean Breast Elastography Study Group, which was formed in August 2013 to perform a multicenter prospective study on the use of elastography for US breast screening. This article is focused on the role of elastography in combination with B-mode US for the evaluation of breast masses. Practical tips for adequate data acquisition and the interpretation of elastography results are also presented.

Diffusion-Weighted Magnetic Resonance Imaging for Breast Cancer Screening in High-Risk Women: Design and Imaging Protocol of a Prospective Multicenter Study in Korea

신희정,이수현,박영진,윤정현,강봉주,윤보라,김태희,고은숙,한부경,추아정,박서영,김학희,문우경 한국유방암학회 2021 Journal of breast cancer Vol.24 No.2

Purpose: Interest in unenhanced magnetic resonance imaging (MRI) screening for breast cancer is growing due to concerns about gadolinium deposition in the brain and the high cost of contrast-enhanced MRI. The purpose of this report is to describe the protocol of the Diffusion-Weighted Magnetic Resonance Imaging Screening Trial (DWIST), which is a prospective, multicenter, intraindividual comparative cohort study designed to compare the performance of mammography, ultrasonography, dynamic contrast-enhanced (DCE) MRI, and diffusion-weighted (DW) MRI screening in women at high risk of developing breast cancer. Methods: A total of 890 women with BRCA mutation or family history of breast cancer and lifetime risk ≥ 20% are enrolled. The participants undergo 2 annual breast screenings with digital mammography, ultrasonography, DCE MRI, and DW MRI at 3.0 T. Images are independently interpreted by trained radiologists. The reference standard is a combination of pathology and 12-month follow-up. Each image modality and their combination will be compared in terms of sensitivity, specificity, accuracy, positive predictive value, rate of invasive cancer detection, abnormal interpretation rate, and characteristics of detected cancers. The first participant was enrolled in April 2019. At the time of manuscript submission, 5 academic medical centers in South Korea are actively enrolling eligible women and a total of 235 women have undergone the first round of screening. Completion of enrollment is expected in 2022 and the results of the study are expected to be published in 2026. Discussion: DWIST is the first prospective multicenter study to compare the performance of DW MRI and conventional imaging modalities for breast cancer screening in high-risk women. DWIST is currently in the patient enrollment phase.

독립적 검사 방법으로서의 확산강조 자기공명영상검사

신희정,이수현,문우경 대한영상의학회 2021 대한영상의학회지 Vol.82 No.1

Diffusion-weighted magnetic resonance imaging (DW MRI) is a fast unenhanced technique that shows promise as a stand-alone modality for cancer screening and characterization. Currently, DW MRI may have lower sensitivity than that of dynamic contrast-enhanced MRI as a standalone modality for breast cancer detection but superior to that of mammography, which may provide a useful alternative for supplemental screening. Standardized acquisition and interpretation of DW MRI can improve the image quality and reduce the variability of the results. Furthermore, high-resolution DW MRI, with advanced techniques and postprocessing, will facilitate better detection and characterization of subcentimeter cancers and reduce false-negatives and false-positives. Future results from ongoing prospective multicenter clinical trials using standardized and optimized protocols will facilitate the use of DW MRI as a stand-alone modality. 확산강조영상은 유방암의 진단과 스크리닝에 있어 독립적 검사 방법으로서의 기대되는 결과를 보여주는 빠른 비조영증강 검사 방법이다. 현재까지의 연구 결과 유방암 진단에 있어 독립적 검사 방법으로서 확산강조영상의 민감도는 역동적 조영증강 검사보다는 낮으나 유방촬영술보다는 높으며, 이로써 유방암 스크리닝에 대한 유용한 대안이 될 수 있을 것으로 보인다. 확산강조영상의 표준화된 영상 획득과 판독을 통해 영상 화질이 개선될 수 있고, 판독 결과의 다양성도 감소할 것으로 기대된다. 또한, 최신 기법과 후처리 기법을 사용한 고해상도확산강조영상을 시행함으로써 1 cm 미만의 작은 암의 발견율을 증가시킬 수 있고, 가음성 및가양성 결과를 감소시킬 것으로 보인다. 현재 한국에서 진행 중인 고위험군 여성에서의 확산강조영상 스크리닝에 대한 다기관 연구 결과가 나온다면 독립적 검사로서의 확산강조영상의사용을 촉진시킬 수 있을 것으로 기대된다.

대기 난류와 열적 블루밍을 겪는 고출력 레이저 빔의 대기 전파 시뮬레이션에 필요한 위상판 개수 분석

윤석영,문우현,김훈 한국광학회 2024 한국광학회지 Vol.35 No.2

본 연구에서는 킬로와트 급 고출력 레이저의 대기 전파 시뮬레이션에 필요한 위상판의 개수를 분석하였다. 킬로와트 급 레이저가 대기 중에 전파될 때, 주로 대기 난류와 열적 블루밍 효과에 영향을 받는다. 이에 따라 split step 방법을 사용하여 대기의 흡수 및 산란에 의한 손실, 그리고 난류와 열적 블루밍으로 인한 빔의 왜곡 현상을 구현할 때, 위상판의 개수는 시뮬레이션의 정확성 및 소요 시간을 결정짓는 중요한 요소이 다. 본 연구에서는 광범위한 대기 난류 조건에서 많은 수의 위상판(예: 150개)을 사용하여 시뮬레이션을 진행하고, 레이저 출력 밀도 2.5 × 10 6W/m 2 (50 cm 직경 레이저 빔의 경우 500 kW 출력) 미만의 고출력 레이저 빔 전파 시뮬레이션에 필요한 위상판 개수에 대한 새로운 가이드 라인을 제시한다. We analyze the number of phase screens required for the simulation of a high-energy laser beam’s propagation over an atmospheric channel. Forhigh-energy lasers exceeding tens of kilowatts (kW) in power, the laser beam is mainly affected by atmospheric turbulence and thermal blooming. When using the split-step method to implement losses due to atmospheric absorption and scattering and distortion of the beam due to turbulence and thermal blooming, the number of phase screens is a critical factor in determining the accuracy and time required for the simulation. By comparing simulation results obtained using a large number of phase screens (e.g. 150 screens) under a wide range of atmospheric turbulence conditions, we provide new guidelines for the number of phase screens required for simulating the beam propagation of a high-power laser below 2.5 × 10 6 W/m 2 (e.g. a 500-kW laser beam having a 50-cm diameter).

Corrigendum: Diffusion-Weighted Magnetic Resonance Imaging for Breast Cancer Screening in High-Risk Women: Design and Imaging Protocol of a Prospective Multicenter Study in Korea

신희정,이수현,박영진,윤정현,강봉주,윤보라,김태희,고은숙,한부경,추아정,박서영,김학희,문우경 한국유방암학회 2022 Journal of breast cancer Vol.25 No.2

.

Ipsilateral Lymphadenopathy After COVID-19 Vaccination in Patients With Newly Diagnosed Breast Cancer

하수민,천종호,이수현,김수연,박아름,김연수,연희라,이유경,조나리야,문우경,장정민 한국유방암학회 2022 Journal of breast cancer Vol.25 No.2

This study aimed to evaluate the imaging and pathological findings in axillary lymph nodes in patients with breast cancer who received concurrent ipsilateral coronavirus disease 2019 (COVID-19) vaccination. Of the 19 women with breast cancer who received concurrent COVID-19 vaccination shot in the arm ipsilateral to breast cancer, axillary lymphadenopathy was observed in 84.2% (16 of 19) of patients on ultrasound (US) and 71.4% (10 of 14) of patients on magnetic resonance imaging (MRI), and 21.0% (4 of 19) of patients were diagnosed with metastasis. Abnormal US and MRI findings of cortical thickening, effacement of the fatty hilum, round shape, and asymmetry in the number or size relative to the contralateral side were noted in more than half of the non-metastatic and metastatic lymph nodes; however, statistical significance was not noted. Axillary lymphadenopathy is commonly observed in patients with breast cancer who receive concurrent ipsilateral COVID-19 vaccination without specific differential imaging features. Thus, understanding the limitations of axillary imaging and cautious interpretation is necessary to avoid overestimation or underestimation of the axillary disease burden.

3D Computer-Aided Detection for Digital Breast Tomosynthesis: Comparison with 2D Computer-Aided Detection for Digital Mammography in the Detection of Calcifications

추아정,조나리야,장정민,김원화,이수현,송성은,신승의,문우경 대한영상의학회 2017 대한영상의학회지 Vol.77 No.2

Purpose: To retrospectively evaluate the performance of 3D computer-aided detection (CAD) for digital breast tomosynthesis (DBT) in the detection of calcifications in comparison with 2D CAD for digital mammography (DM). Materials and Methods: Between 2012 and 2013, both 3D CAD and 2D CAD systems were retrospectively applied to the calcification data set including 69 calcifications (31 malignant calcifications and 38 benign calcifications) and the normal data set including 20 bilateral normal mammograms. Each data set consisted of paired DBT and DM images. Sensitivities for the detection of malignant calcifications were calculated from the calcification data set. False-positive mark rates were calculated from the normal data set. They were compared between the two systems. Results: Sensitivities of 3D CAD [100% (31/31) at levels 2, 1, and 0] were same as those of the 2D CAD system [100% (31/31) at levels 2 and 1] (p = 1.0, respectively). The mean value of false-positive marks per view with 3D CAD was higher than that with 2D CAD at level 2 (0.52 marks ± 0.91 vs. 0.07 marks ± 0.26, p = 0.009). Conclusion: 3D CAD for DBT showed equivalent sensitivity, albeit with a higher falsepositive mark rate, than 2D CAD for DM in the detection of calcifications.