• Investigative Magnetic Resonance Imaging
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• v.12 no.2
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• pp.178-187
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• 2008

Purpose : To evaluate and compare the diagnostic accuracy of MRI and ultrasound(US) for estimation of invasion depth of gastric carcinoma by correlation with histopathologic findings in vitro and to find out the best MR pulse sequence for detection and accurate delineation of tumor. Materials and Methods : Resected specimen of total or subtotal gastrectomy from 53 patients with gastric carcinoma were done of imaging studies of MRI and US. And US was examined by using high frequency linear transducer for tumor invasion depth by a radiologist. In each case, both imaging findings of MRI and US were evaluated independently for tumor detection and invasion depth by consensus of two radiologists and were compared the diagnostic accuracy between two imaging modalities according to the histopathologic findings. MR imaging with five MR pulse sequences, spin echo T1 and in- and out-of phase gradient echo T1 weighted images, FSE and SSFSE T2 weighted images, were performed. Five MR pulse sequences were evaluated and compared on the point of detection and accurate distinction of tumor from surrounding normal tissue. Results : In EGC, diagnostic accuracy of US(77%) was superior than that of MRI(59%) but no statistically significant difference was noted between two imaging modalities(p=0.096). In AGC, both imaging modalities of MRI and US showed relatively high diagnostic accuracy as 97% and 84% respectively. Diagnostic accuracy of MRI was statistically better than that of US at the significant level(p<0.001). The best MR pulse sequence among five in each specimen was FSE T2WI(75.5%, 40/53) in both EGC and AGC. In AGC, FSE T2WI showed excellent imaging quality by showing very high ratio (93.5%, 29/31) of accurate delineation of tumor. Conclusion : MRI and US show relatively high diagnostic accuracy in the evaluation of tumor invasion depth of resected specimen in AGC. The most excellent pulse sequence of MRI for the evaluation of tumor invasion depth is FSE T2WI on the point of detection and accurate delineation of tumor in both EGC and AGC.

• The Journal of the Acoustical Society of Korea
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• v.17 no.6
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• pp.79-84
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• 1998

초음파 진단장치는 X선 촬영과 달리 인체에 해를 주지 않고 계속적으로 장시간 관 찰할 수 있고 실시간으로 영상을 볼 수 있으며, 또 타장비에 비해 가격이 저렴하고 소형이 라는 장점이 있다. 현재는 이 영상들을 대용량 저장매체에 저장되어 컴퓨터를 통해 재생하 여 볼 수 있게 되었다. 본 논문에서는 이러한 막대한 양의 영상데이터를 검색하기 위한 새 로운 검색방법을 제시한다. 제안하는 검색방법은 검색을 원하는 정지화상의 컬러이미지를 제시하면 시스템이 이를 자동으로 분석하여 이미지 데이터베이스에 저장된 유사한 이미지데 이터들과 관련된 정보들을 질의결과로 나타내어 쉽게 검색하고자 한다. 이를 위하여 사용자 가 제시한 정지화상을 Bitmap으로 구성하고, Bitmap전체의 비디오 메모리에서 검색할 부분 영역을 검색대상으로 설정한다. 이 값을 key값으로 우선적으로 여기에 원하는 유사비를 설 정한 후 전체 동화상의 각 프레임에서 추출한 비디오 메모리 데이터와 검색 화면의 비디오 메모리를 Pixel별로 비교하여, 사용자가 원하는 영상데이터의 위치point 값과 유사비율값을 보관한다. point값으로 보관된 것을 유사비율에 따라 우선 순위를 정하여 데이터베이스에 보 관하고 이 보관된 후보 이미지들을 순위별로 화면에 나타내어 사용자가 원하는 이미지데이 터를 쉽고 빠르게 검색할 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.232-235
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• 2013

간 질환 진단을 위한 의료 초음파 동영상에서 호흡으로 인한 영상의 흔들림 현상은 전이시간(transit time) 요소와 같은 진단 파라미터의 신뢰도를 저하시킬 뿐만 아니라, 정확한 병변 형태의 추출을 어렵게 한다. 본 연구에서는 호흡 주기를 자동으로 감지하고 이를 기반으로 ROI 를 추적하는 방법과 프레임 샘플링을 통하여 TIC(Time-Intensity Curve) 형태의 왜곡을 보정하는 방법을 고찰한다. 세부적으로 동적 가중치와 모멘텀 요소를 고려한 추적 기법을 제시하고 유용성을 평가한다. 또한 호흡주기와 프레임간 유사도(similarity)를 기반으로 한 영상 샘플링 기법을 제안하고 이로부터 신호의 왜곡을 보정할 수 있음을 보인다.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.4
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• pp.348-353
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• 2004

This study is aimed for the implementation of ultrasonic method to assess the reliability of turbine bearings. A modified ultrasonic immersion technique was carried out in both laboratory experiment and field application. From the laboratory results, we confirmed that the condition of interface layer between the babbitt and base metal be monitored by the C-Scan. The C-scan image by the ultrasonic immersion test can be used successfully to observe the condition of interface layer. The testing with a focused transducer provides a promising approach for estimating the extent of the damaged region and observing the interface layer effectively. The difference of the ultrasonic reflection ratio between the bonding and debonding area at the interface layer is one of the key parameters for assessing the extent of the damaged area; additionally, the reflection amplitude exhibits a favorable correlation with the overall damage level. The technique developed in this study was applied to the inspection of the turbine bearings at several power plants in Korea whereby the applicability in the field can be ascertained.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.7 no.1
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• pp.49-66
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• 2014

Traditionally, cervical interventions have been performed under fluoroscopy. But radiation exposure is the major concern when obtaining fluoroscopic images and even under real-time fluoroscopy with contrast media or CT guidance, some cases of serious spinal cord injuries, cerebellar and brain stem infarction have been reported by unintentional intra-arterial injections especially during the transforaminal root blocks. Recently, the use of ultrasound-guided cervical interventions have increased. Ultrasound offers visualization of soft tissues including major neurovascular structures and also allows to observe the spread of injectant materials around the target structure. Ultrasound is radiation free, easy to use and the image can be performed continuously while the injectant is visualized in real-time, increasing the precision of injection. Importantly, ultrasound allows visualization of major nerves and vessels and thus leads to improve safety of cervical interventions by decreasing the incidence of injury or injection into nearby vasculature. We therefore reviewed to investigate the feasibility of performing cervical interventions under real-time ultrasound guidance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.655-657
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• 2021

It is challenging to find breast ultrasound image training dataset to develop an accurate machine learning model due to various regulations, personal information issues, and expensiveness of acquiring the images. However, studies targeting transfer learning for ultrasound breast cancer images classification have not been able to achieve high performance compared to radiologists. Here, we propose an improved transfer learning model for ultrasound breast cancer classification using publicly available dataset. We argue that with a proper combination of ImageNet pre-trained model and optimizer, a better performing model for ultrasound breast cancer image classification can be achieved. The proposed model provided a preliminary test accuracy of 99.5%. With more experiments involving various hyperparameters, the model is expected to achieve higher performance when subjected to new instances.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.5
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• pp.484-493
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• 2012

Since the 1980s, there have been many research activities devoted to quantitatively characterizing and imaging human tissues based on sound speed, attenuation coefficient, density, nonlinear B/A parameter, etc., but those efforts have not yet reached the stage of commercialization. However, a new imaging technology termed elastography, which was proposed in the early 1980s, has recently been implemented in commercial clinical ultrasound scanners, and is now being used to diagnose prostates, breasts, thyroids, livers, blood vessels, etc., more quantitatively as a complementary adjunct modality to the conventional B-mode imaging. The purpose of this article is to introduce and review various elastographic algorithms for use in quasistatic or static compression type elasticity imaging modes. Most of the algorithms are based on the crosscorrelation or autocorrelation function methods, and the fundamental difference is that the time shift is estimated by changing the lag variable in the former, while it is directly obtained from the phase shift at a fixed lag in the latter.

• Journal of the Korean Society of Radiology
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• v.84 no.1
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• pp.92-109
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• 2023

In patients with thyroid nodules, ultrasonography (US) has been established as a primary diagnostic imaging method and is essential for treatment decision. The Korean Thyroid Imaging Reporting and Data System (K-TIRADS) is a pattern-based, US malignancy risk stratification system that can easily diagnose nodules during real-time ultrasound examinations. The 2021 K-TIRADS clarified the US criteria for nodule classification and revised the size thresholds for nodule biopsy, thereby reducing unnecessary biopsies for benign nodules while maintaining the appropriate sensitivity to detect malignant tumors in patients without feature of high risk thyroid cancer. Thyroid radiology practice has an important clinical role in the diagnosis and non-surgical treatment of patients with thyroid nodules, and should be performed according to standard practice guidelines for proper and effective clinical care.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.531-537
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• 2019

The purpose of this study was to analyze the relationship between hematologic hyperlipemia index and severity of fatty liver abdominal ultrasonography. A total of 412 adults from January 1, 2017 to December 31, 2017 who underwent abdominal ultrasonography and hematologic data within 3 months of the ultrasound examination, were the target of the investigation. As a result of the study, the hematological values according to the degree of fatty liver were statistically significant in triglyceride, AST and ALT (p<.05), fatty liver was associated with gender, triglyceride, AST and ALT (p<.05). In conclusion, the degree of fatty liver was not directly related to the hematologic value of hyperlipidemia, but we confirmed the necessity of co-management with fatty liver and hyperlipidemia by confirming its relevance.

• Journal of IKEEE
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• v.26 no.1
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• pp.27-35
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• 2022

This paper proposes an ultrasound vessel-pattern imaging algorithm with low computational complexity. The proposed imaging algorithm reconstructs blood-vessel patterns by only detecting blood flow, and can be applied to a real-time signal processing hardware that extracts an ultrasonic finger-vessel pattern. Unlike a blood-flow imaging mode of typical ultrasound medical imaging device, the proposed imaging algorithm only reconstructs a presence of blood flow as an image. That is, since the proposed algorithm does not use an I/Q demodulation and detects a presence of blood flow by accumulating an absolute value of the clutter-filter output, a structure of the algorithm is relatively simple. To verify a complexity of the proposed algorithm, a simulation model for finger vessel was implemented using Field-II program. Through the behavioral simulation, it was confirmed that the processing time of the proposed algorithm is around 54 times less than that of the typical color-flow mode. Considering the required main building blocks and the amount of computation, the proposed algorithm is simple to implement in hardware such as an FPGA and an ASIC.