• 한국통신학회논문지
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• 제29권3C호
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• pp.374-386
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• 2004

유방암은 최근에 빠르게 증가하고 있는 여성 암중의 하나이며 그 발명원인이 불명확하여 조기 검출만이 생존율을 높일 수 있는 유일한 방법이다. 본 논문에서는 효율적으로 미소석회질의 의심 영역을 검출할 수 있는 방법에 대하여 설명한다. 본 논문에서는 디지털 마모램 영상에 대한 통계적 분석으로부터 일반적인 미소석회질의 특성을 분석한 후 분석된 자료를 이용하여 다단 신경망을 구성한 후 의심영역으로 간주되는 ROI를 검출한다. ROI 검출을 위하여 4단계로 구성되는 알고리즘을 제안하며 전처리 과정, 다단계 thresholding, 선형필터를 이용한 1차 미소석회질 선별작업, 다단계 신경망을 이용한 2차 미소석회질 검출이 포함된다. 선형필터를 이용한 1차 선별작업에서는 모든 미소석회질을 검출할 수 있었고 유방조직 제거를 통한 신경망에서의 작업처리 감소율이 86％로 나타났다. 2단 신경망을 이용한 2차 미소석회질 검출단계에서 첫 번째 신경망에서는 미소석회질의 형태적 특성을 기반으로 11개의 특징 값들을 정의하였으며 모든 데이터에 대한 실험 결과 평균 96.66％의 인식률을 보였다. 그리고 두 번째 신경망에서는 첫 번째 인식 결과 값과 미소석회질의 군집특성을 이용하기 위해 첫 번째 인식결과를 토대로 조사된 군집분포 여부를 특징 값으로 사용하였으며 그 결과 1차 신경망보다 높은 평균 98.26％의 인식률을 보였다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권24호
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• pp.10665-10673
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• 2015

Background: We wished to analyse patterns of use of needle biopsy procedures by BreastScreen Australia (BSA) accredited programs to identify areas for improvement. Design: BSA services provided anonymous data regarding percutaneous needle biopsy of screen detected lesions assessed between 2005-2009. Results: 12 services, from 5 of 7 Australian states and territories provided data for 18212 lesions biopsied. Preoperative diagnosis rates were 96.84% for lesion other than microcalcification (LOTM) and 93.21% for microcalcifications. At surgery 97.9% impalpable lesions were removed at the first procedure. Of 11548 Microcalcification (LOTM) biopsied, 46.9% were malignant. The final diagnosis was reached by conventional core biopsy (CCB) in 72.46%, FNAB in 21.33%, VACB in 1.69% and open biopsy in 4.52% of lesions. FNA is being limited to LOTM with benign imaging After FNAB, core biopsy was required for 38% of LOTM. In LOTM the mean false positive rate (FPR) was 0.36% for FNAB, 0.06% for NCB and 0% for VACB. Diagnostic accuracy was 72.75% for FNAB and 92.1% for core biopsies combined. Of 6441 microcalcifications biopsied 2305 (35.8%) were malignant. Microcalcifications are being assessed primarily by NCB but 6.57% underwent FNAB, 45.6% of which required NCB. False positive diagnoses were rare. FNR was 5% for NCB and 1.53% for VACB. Diagnostic accuracy was 73.52% for FNAB, 86.29% for NCB and 88.63% for VACB. Only 8 of 12 services had access to VACB facilities. Conclusions: BSA services are selecting lesions effectively for biopsy and are achieving high preoperative diagnosis rates. Gaps in the present accreditation standards require further consideration.

• 대한방사선기술학회지:방사선기술과학
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• 제40권4호
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• pp.575-580
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• 2017

Moire artifact는 미세병변과 주파수 대역이 중첩되기 때문에 moire artifact를 제거하는 Image processing software를 사용할 경우 미세 병변의 손실을 가져올 수 있다. 본 연구에서는 SD(Sprague Dawley) Rat에 microcalcification과 microfracture와 같은 미세병변을 임의로 형성하여 영상화하고, reference 영상과 grid suppression software를 사용한 영상, optimizied grid 영상을 비교 분석하였다. 영상은 두 명의 영상의학과 전문의가 컨소시엄을 형성하여 판독하였고, 판독 결과 값은 McNemar's test 이용하여 평가하였다. 73개의 microcalcifications 중 Grid suppression후 13 cases에서, optimized grid를 사용한 영상은 3 cases에서 영상의 손실이 확인되어 Grid suppression후의 영상이 통계적으로 유의하게 영상 손실을 발생하고 있음을 보여주고 있다(p=0.021). 총 53개의 fracture line은 Grid suppression을 시행한 후 영상에서 19 cases가 영상의 손실을 보였고, optimized grid를 사용한 영상에서는 영상손실이 없는 것으로 판독되었다. 따라서 미세병변을 진단하는 영상에 있어 moire artifact를 제거하기 위한 grid suppression software 사용은 신중하게 고려되어야 할 것이다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.68-71
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• 1997

The early detection of brest cancer is clearly a key ingredient for any strategy designed to reduce breast cancer mortality. Microcalcification(MCC) is one of the primary signatures to discriminate between normal and cancerous tissue. The detection and locating procedures can be automated by digital image processing, however, MCCs have various sizes, shapes, and intensity levels in film images, so it is difficult to find accurate locations and sizes. Firstly, we made quantitative analysis for many characteristic features of mammograms that can be used to segment MCCs from normal tissues. Secondly, we developed algorithms proper to segmentation like pattern matching. The performance was evaluated with TP and FP rates.

• Journal of Yeungnam Medical Science
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• 제21권2호
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• pp.224-230
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• 2004

유방암 검사와 함께 시행한 갑상선 선별 초음파 검사에서 나타난 전형적인 갑상선 유두암의 소견은 경계가 불분명한 고형의 저에코 결절로 나타나고 점상 혹은 미세석회화를 보일 수 있어 이러한 결절에서는 조직 검사를 통한 확진이 필요하다.

• 대한디지털의료영상학회논문지
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• 제16권2호
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• pp.25-29
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• 2014

The full-field digital mammography (FFDM), which has been known as a digital breast imaging system, carries out more outstanding performance than the screen-film mammography in overall image quality, skin & nipple, description of pectoral muscle and expression of micro-calcification. Thus, in this thesis, I perform experiments for both the enhancement of image quality and accurate estimation of the result in question, when detecting the very tiny-sized lesions in mammography. The image of digital breast X-rays is the important diagnostic tool for detecting early breast cancer and micro calcification lesion. The experiment of how much compression rate has an effect on the result of diagnosis in the case of microcalcification lesion, with JPEG2000 40:1 compression and over 50% enlargement led to obscure or definitely unacceptable diagnostic results is performed. And in another study of assessment of PSNR degree. I recognized the importance of standardized management system in mammography, where not to mention the accurate reading of the image has the most crucial role in diagnosis

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2006년도 가을 학술발표논문집 Vol.33 No.2 (A)
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• pp.1-5
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• 2006

본 논문에서는 유방암의 조기발견에 있어서 중요한 소견중 하나인 군집화된 미세석회질을 유방촬영 영상으로부터 자동으로 분석 및 검출하는 컴퓨터 보조 검출 시스템을 구현하였다. 전처리단계로서 유방영상에 메디안 필터를 사용하여 잡음을 제거하고, 히스토그램과 레이블링 연산을 수행하여 실제 유방영역만을 추출 하는 작업을 구현하였다. 그런 후에 추출된 실제 유방영역에서 LoG (Laplacian of Gaussian)연산을 수행하고 히스토그램을 분석하여 이진화를 수행한후에 후보점을 검출하였다. 마지막으로 이를 이용하여 영역확장 알고리즘을 수행하여 미세석회질의 후보영역을 검출한 후, 미세석회질간의 거리를 분석하여 최종 관심영역을 추출하였다. 데이터베이스는 총 20개의 MIAS Mini Database의 맘모그램 영상을 사용하였으며 실험결과 89%라는 검출 성능을 얻을 수 있었다.

• Korean Journal of Radiology
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• 제2권2호
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• pp.113-116
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• 2001

In Asia, mammography following the injection of foreign materials into the breasts for cosmetic augmentation is frequently seen and diagnosis based on the typical radiologic findings is straightforward. We report the unusual radiologic findings in two patients with foreign body granulomas caused by injected foreign materials and discovered incidentally during screening work up. The mammographic findings were bilateral, hyperdense, spiculated masses, with occasional microcalcification, and at sonography, markedly hypoechoic, spiculated solid masses, located near the pectoralis muscle and partly extending into it, were observed. These radiologic findings mimicked malignancy.

• Asian Pacific Journal of Cancer Prevention
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• 제15권12호
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• pp.4929-4932
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• 2014

Objective: To compare the mammogarphic appearance between breast cancer patients aged <40 and ${\geq}40$ years. Methods: Needle localization and biopsy of suspicious mammographic lesions identified 1,959 breast carcinomas in a single institution from Jun 2012 to Apr 2013. According to the age, we divided patients into two groups: <40 and ${\geq}40$ years old, and analyzed mammographic appearance separately. Results: Young patients had 44.2% foci with calcification, but old patients only had 39.4% (P<0.001). In younger group, the ratios of cases according to mass density were 41.8% or higher, 58.2% equivalent and lower. In older group, the ratios were 55.5 % and 44.5%, respectively. There were statistical differences between high density and others (P<0.05). The ratios of cases according to mass margin were 13.9% circumscribed and microlobulated, 86.1% indistinct and spiculated in the younger group, as compared to 6.5% and 93.5%, respectively, in the older group (P<0.05). Conclusions: Mammographic findings differ between young and old patients with breast cancer, for example regarding mass density, mass margin and microcalcification ratios.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.415-417
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• 2002

Images of microcalcification specks showed large variation in conventional radiographs of phantoms which are approved for mammography image quality standard by the American College of Radiology (ACR). This kind of variation is not appropriate for image quality standards because the number of specks are visually counted in images and that number is important in image quality evaluation. Our study using synchrotron radiation (SR) imaging revealed the overlapping of micro-sized air bubble(s) to some specks, and also the structural deformation or crackings. Eight phantoms approved by ACR from two different makers and an air-bubble phantom were examined. SR imaging was performed at a synchrotron radiation facility, SPring-8, in Japan. The image-detector was a fluorescent-screen optical-lens coupling system using a CCD camera with a spatial resolution of 6 $\square$m. Objects when imaged with longer sample-to-detector distance show edge enhancement due to a difference in refraction indices, that is refraction enhancement. Refraction-enhanced SR images revealed that some of specks carried foreign objects, which were proven to be air. In phantoms provided by one maker, attaching/overlapping airs were observed for 62 out of 150 specks (41%) , with a higher incidence for the smallest specks. A speck becomes hardly visible in a conventional radiograph when air(s) overlaps the majority part of a speck, though depending on the size of the air-inclusion and on its configuration. Those airs might have been adsorbed on a speck surface before being embedded and then introduced into the matrix together with specks. Our study using SR imaging has clearly shown the nature of defects in some mammography phantoms which seriously degrade the quality as an image standard.