• Korean Journal of Radiology
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• 제24권12호
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• pp.1190-1199
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• 2023

Objective: This study aimed to investigate the feasibility of ultrafast magnetic resonance imaging (MRI) and radiomic features derived from breast MRI for predicting the upstaging of ductal carcinoma in situ (DCIS) diagnosed using percutaneous needle biopsy. Materials and Methods: Between August 2018 and June 2020, 95 patients with 98 DCIS lesions who underwent preoperative breast MRI, including an ultrafast sequence, and subsequent surgery were included. Four ultrafast MRI parameters were analyzed: time-to-enhancement, maximum slope (MS), area under the curve for 60 s after enhancement, and time-to-peak enhancement. One hundred and seven radiomic features were extracted for the whole tumor on the first post-contrast T1WI and T2WI using PyRadiomics. Clinicopathological characteristics, ultrafast MRI findings, and radiomic features were compared between the pure DCIS and DCIS with invasion groups. Prediction models, incorporating clinicopathological, ultrafast MRI, and radiomic features, were developed. Receiver operating characteristic curve analysis and area under the curve (AUC) were used to evaluate model performance in distinguishing between the two groups using leave-one-out cross-validation. Results: Thirty-six of the 98 lesions (36.7%) were confirmed to have invasive components after surgery. Compared to the pure DCIS group, the DCIS with invasion group had a higher nuclear grade (P < 0.001), larger mean lesion size (P = 0.038), larger mean MS (P = 0.002), and different radiomic-related characteristics, including a more extensive tumor volume; higher maximum gray-level intensity; coarser, more complex, and heterogeneous texture; and a greater concentration of high gray-level intensity. No significant differences in AUCs were found between the model incorporating nuclear grade and lesion size (0.687) and the models integrating additional ultrafast MRI and radiomic features (0.680-0.732). Conclusion: High nuclear grade, larger lesion size, larger MS, and multiple radiomic features were associated with DCIS upstaging. However, the addition of MS and radiomic features to the prediction model did not significantly improve the prediction performance.

• 대한영상의학회지
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• 제84권2호
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• pp.345-360
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• 2023

국내에 자기공명영상의 보급의 증가와 함께 유방 자기공명영상의 건수도 지속적으로 증가하고 있다. 하지만 이에 비해 자기공명영상 유도하 조직생검술 및 침위치결정술과 같은 유방의 중재적 시술은 초음파 유도하 시술이나 입체정위생검술에 비해 많이 이루어지지 않는다. 유방 자기공명영상은 다른 유방 영상 검사들에 비해 높은 민감도를 보이는 검사법이지만 그 특이도는 제한되는 검사법이기 때문에, 자기공명영상에서만 발견된 병변들은 자기공명영상 유도하 조직생검술이나 자기공명영상 유도하 침위치결정술을 통한 수술적 절제를 통하여 병리적 진단이 이루어져야 한다. 이러한 배경을 바탕으로, 본 종설에서는 자기공명영상 유도하 유방의 중재적 시술들의 적응증, 시술 방법, 시술 과정에서의 여러 고려 사항 및 제한점들에 대해 다루고자 한다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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• pp.1-6
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• 2007

Two impedance imaging systems of multi-frequency electrical impedance tomography (MFEIT) and magnetic resonance electrical impedance tomography (MREIT) are described. MFEIT utilizes boundary measurements of current-voltage data at multiple frequencies to reconstruct cross-sectional images of a complex conductivity distribution (${\sigma}+i{\omega}{\varepsilon}$) inside the human body. The inverse problem in MFEIT is ill-posed due to the nonlinearity and low sensitivity between the boundary measurement and the complex conductivity. In MFEIT, we therefore focus on time- and frequency-difference imaging with a low spatial resolution and high temporal resolution. Multi-frequency time- and frequency-difference images in the frequency range of 10 Hz to 500 kHz are presented. In MREIT, we use an MRI scanner to measure an internal distribution of induced magnetic flux density subject to an injection current. This internal information enables us to reconstruct cross-sectional images of an internal conductivity distribution with a high spatial resolution. Conductivity image of a postmortem canine brain is presented and it shows a clear contrast between gray and white matters. Clinical applications for imaging the brain, breast, thorax, abdomen, and others are briefly discussed.

• Archives of Plastic Surgery
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• 제44권2호
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• pp.101-108
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• 2017

Background Understanding the female breast fascial system is of paramount importance in breast surgery. Little was written about breast ligaments. Most articles refer to Cooper's work without further anatomical studies. Lately, a horizontal septum has been described conveying nerves and vessels to the nipple areola complex. Methods During the surgical dissection of the lower part of the breast, in supero-medial technique for breast reduction operations, a fascial septum between the lower two quadrants was detected. This fibrous septum was studied through anatomic dissection of breast tissues during routine breast reshaping procedures that was done on 30 female patients. Magnetic resonance imaging (MRI) was performed preoperatively in all cases and correlated with the intraoperative findings. In the other five cases, outside the clinical study, the imaging was done during routine investigation for breast swellings. Results A vertical septum was identified in the lower part of the breast, lying at the breast meridian between the two lower quadrants. It is a tough bi-laminated structure that extends from the middle of the infra-mammary crease caudally to nipple-areola complex cranially and from the pectoral fascia posteriorly to the overlying skin anteriorly. This was proved by MRI findings. Conclusions This study describes a new inferior vertical septum which separates the lower half of the breast into two definite anatomical compartments: medial and lateral.

• 대한영상의학회지
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• 제82권4호
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• pp.889-902
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• 2021

목적 자기공명영상에서 추가적으로 발견된 조영증강 병소에 대한 조영증강 초음파의 진단능력을 평가하고 조영증강 초음파의 정량 분석을 사용하여 유방 동적 조영증강 자기공명영상과 유사한 운동 패턴 결과를 얻을 수 있는지 분석하였다. 대상과 방법 단일 센터 전향적 연구로 진행하였고, 총 71개의 자기공명영상에서 추가적으로 발견된 조영증강 병소가 포함되었다. 이러한 병소에 대해 조영증강 초음파를 시행하였고 Breast Imaging-Reporting and Data System (이하 BI-RADS)에 따라 분류하였다. 그리고 모든 병소의 BI-RADS 분류를 조직학적 결과와 비교하여 조영증강 초음파의 민감도, 특이도 및 진단 정확도를 계산하였다. 조영증강 초음파와 동적 조영증강 자기공명영상의 운동 패턴사이의 일치도는 가중 카파 분석을 사용하여 평가되었다. 결과 조영증강 초음파에서 총 46개의 병소가 BI-RADS 4B, 4C, 5로 분류되었고, 25개의 병소가 BI-RADS 3, 4A로 분류되었다. 자기공명영상에서 추가적으로 발견된 조영증강 병소에 대한 조영증강 초음파의 진단 능력은 84.9%의 민감도, 94.4%의 특이도 및 97.8%의 긍정적 예측값으로 우수하였다. 총 57/71 (80%) 병소는 조영증강 초음파와 동적 조영증강 자기공명영상 운동 패턴 결과가 일치하였고 가중 카파 값 0.66으로 좋은 일치도를 나타냈다. 부분 군 분석에서 양성 병소는 우수한 일치를 보였고(가중 카파 값 = 0.84), 관내암종은 좋은 일치를 보였다(가중 카파 값 = 0.69). 결론 MRI에서 추가 검출된 유방 결절에 대한 조영증강 초음파의 진단 능력은 우수했다. 양성 및 관내암종 병소에서 동적 조영증강 자기공명영상과 조영증강 초음파의 운동 패턴 결과는 좋은 일치도를 보였다.

• Korean Journal of Radiology
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• 제19권6호
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• pp.1110-1118
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• 2018

Objective: To perform a meta-analysis to quantitatively assess functional magnetic resonance imaging (MRI) in the diagnosis of locally recurrent prostate cancer. Materials and Methods: A comprehensive search of the PubMed, Embase, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews was conducted from January 1, 1995 to December 31, 2016. Diagnostic accuracy was quantitatively pooled for all studies by using hierarchical logistic regression modeling, including bivariate modeling and hierarchical summary receiver operating characteristic (HSROC) curves (AUCs). The Z test was used to determine whether adding functional MRI to T2-weighted imaging (T2WI) results in significantly increased diagnostic sensitivity and specificity. Results: Meta-analysis of 13 studies involving 826 patients who underwent radical prostatectomy showed a pooled sensitivity and specificity of 91%, and the AUC was 0.96. Meta-analysis of 7 studies involving 329 patients who underwent radiotherapy showed a pooled sensitivity of 80% and specificity of 81%, and the AUC was 0.88. Meta-analysis of 11 studies reporting 1669 sextant biopsies from patients who underwent radiotherapy showed a pooled sensitivity of 54% and specificity of 91%, and the AUC was 0.85. Sensitivity after radiotherapy was significantly higher when diffusion-weighted MRI data were combined with T2WI than when only T2WI results were used. This was true when meta-analysis was performed on a per-patient basis (p = 0.027) or per sextant biopsy (p = 0.046). A similar result was found when $^1H$-magnetic resonance spectroscopy ($^1H$-MRS) data were combined with T2WI and sextant biopsy was the unit of analysis (p = 0.036). Conclusion: Functional MRI data may not strengthen the ability of T2WI to detect locally recurrent prostate cancer in patients who have undergone radical prostatectomy. By contrast, diffusion-weight MRI and $^1H$-MRS data may improve the sensitivity of T2WI for patients who have undergone radiotherapy.

• 정보처리학회논문지B
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• 제14B권6호
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• pp.431-436
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• 2007

자기공명영상(Magnetic Resonance Imaging:MRI)은 물과 지방 사이에 화학적 이동 현상을 가지고 있고 지방에 의해 구조적 현상이 나타난다. 또한 지방은 기본적으로 강한 신호를 가지고 있어 잘못된 인공물을 형성한다. 그래서 지방소거(fat suppression)에 대해 연구하고자 한다. MRI에서 지방소거(fat suppression)방법만을 사용하여 진단하는데 약간의 어려움은 있지만 기본은 화학적 이동 선택 포화(chemical shift selective saturation : CHESS) pulse 방법을 이용하여 물과 지방 phantom을 가지고 지방소거(fat suppression)를 연구하는데 목적이 있다. 본 연구에서 CHESS pulse를 matlap 프로그램을 이용 Map pulse로 알맞게 design하고 Pre saturation을 하기 위한 pulse diagram이 가능하였고, fat phantom과 water phantom을 실험하여 지방소거 기법(fat saturation)의 효과를 볼 수가 있었으며 임상 적용 부위로 경추(C-SPINE), 요추(L-SPINE), 가습(BREAST)에 적용하여 의료영상진단에 있어 화학적 이동 선택 포화 CHESS pulse의 지방소거(fat suppression)는 유용한 방법임을 증명하였다.(충남대학병원 G.E 1.5T MR를 이용하여 실험하였다.)

• 대한영상의학회지
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• 제83권5호
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• pp.1189-1194
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• 2022

유방의 겨드랑꼬리에 발생한 악성 종양은 유방의 특정 해부학적 위치에서 발생하는 유방암의 한 종류이며 발생률은 0.3% 정도로 드문 질환이다. 이는 겨드랑이에서 발생하는 연부조직 종양, 액와부 부유방에서 발생한 유방암, 유방암의 림프절 전이 또는 다른 원발암의 림프절 전이 등과 감별이 필요하다. 저자들은 겨드랑이 종물을 주소로 내원한 47세 환자에서 유방촬영술, 초음파, 전산화단층촬영, 자기공명영상을 통해 겨드랑꼬리 유방암을 진단한 증례를 경험하여 보고하고자 한다.

• Korean Journal of Radiology
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• 제25권1호
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• pp.11-23
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• 2024

Objective: To investigate whether reader training improves the performance and agreement of radiologists in interpreting unenhanced breast magnetic resonance imaging (MRI) scans using diffusion-weighted imaging (DWI). Materials and Methods: A study of 96 breasts (35 cancers, 24 benign, and 37 negative) in 48 asymptomatic women was performed between June 2019 and October 2020. High-resolution DWI with b-values of 0, 800, and 1200 sec/mm² was performed using a 3.0-T system. Sixteen breast radiologists independently reviewed the DWI, apparent diffusion coefficient maps, and T1-weighted MRI scans and recorded the Breast Imaging Reporting and Data System (BI-RADS) category for each breast. After a 2-h training session and a 5-month washout period, they re-evaluated the BI-RADS categories. A BI-RADS category of 4 (lesions with at least two suspicious criteria) or 5 (more than two suspicious criteria) was considered positive. The per-breast diagnostic performance of each reader was compared between the first and second reviews. Inter-reader agreement was evaluated using a multi-rater κ analysis and intraclass correlation coefficient (ICC). Results: Before training, the mean sensitivity, specificity, and accuracy of the 16 readers were 70.7% (95% confidence interval [CI]: 59.4-79.9), 90.8% (95% CI: 85.6-94.2), and 83.5% (95% CI: 78.6-87.4), respectively. After training, significant improvements in specificity (95.2%; 95% CI: 90.8-97.5; P = 0.001) and accuracy (85.9%; 95% CI: 80.9-89.8; P = 0.01) were observed, but no difference in sensitivity (69.8%; 95% CI: 58.1-79.4; P = 0.58) was observed. Regarding inter-reader agreement, the κ values were 0.57 (95% CI: 0.52-0.63) before training and 0.68 (95% CI: 0.62-0.74) after training, with a difference of 0.11 (95% CI: 0.02-0.18; P = 0.01). The ICC was 0.73 (95% CI: 0.69-0.74) before training and 0.79 (95% CI: 0.76-0.80) after training (P = 0.002). Conclusion: Brief reader training improved the performance and agreement of interpretations by breast radiologists using unenhanced MRI with DWI.

• Investigative Magnetic Resonance Imaging
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• 제17권3호
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• pp.224-231
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• 2013

목적 : 유방암이 진단된 환자에서 시행한 자기공명영상에서 배경 실질 조영 정도에 따른 추가적인 조직 검사율 및 악성률의 차이를 알아 보고자 하였다. 대상 및 방법 : 유방암을 진단받고 유방 자기공명영상을 촬영한 322명의 환자를 대상으로, 2명의 영상의학과 의사가 이들의 유방 자기공명영상을 분석하여 배경 실질 조영 증강 정도를 평가하였으며, 판독지를 통해 추가적인 BI-RADS 범주 4 이상의 병변 유무를 확인하였다. 추가적인 BI-RADS 범주 4 이상의 병변에 대해서는 조직검사를 시행하였고, 악성률을 구하기 위해 조직검사 결과를 확인하였다. 결과 : 총 322명의 유방암 환자의 배경 실질 조영 증강 단계별 환자수는 최소 조영 증강 47.5%, 경한 조영 증강 28.9%, 중간 조영 증강 12.4% 그리고 현저한 조영 증강 11.2%였다. 이 중 70예에서 추가적으로 악성이 의심되는 조영 증강 병변이 발견되었고, 4예를 제외한 66예에서 조직 검사가 시행되었다. 배경 실질 조영 증강이 적은 경우 (최소/경한 조영 증강)와 많은 경우 (중간/현저한 조영 증강) 에 따른 조직 검사율은 각각 19.9%, 22.3%이었고, 악성률은 각각 6.5%, 5.2%이었으나, p-value가 각각 0.77, 0.88로 통계적으로 유의한 차이를 보이지 않았다. 결론 : 유방암이 진단된 환자에서 시행한 자기공명영상에서 배경 실질 조영 정도와 조직 검사율 및 악성률 사이에는 차이가 없었다.