• 대한의용생체공학회:의공학회지
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• 제28권6호
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• pp.803-810
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• 2007

Although synthetic aperture focusing techniques can improve the spatial resolution of ultrasound imaging, they have not been employed in a commercial product because they require a real-time N-channel beamformer with a tremendously increased hardware complexity for simultaneous beamforming along M multiple lines. In this paper, a hardware-efficient beamformer architecture for synthetic aperture focusing is presented. In contrast to the straightforward design using NM delay calculators, the proposed method utilizes only M delay calculators by sharing the same values among the focusing delays which should be calculated at the same time between the N channels for all imaging points along the M scan lines. In general, synthetic aperture beamforming requires M 2-port memories. In the proposed beamformer, the input data for each channel is first upsampled with a 4-fold interpolator and each polyphase component of the interpolator output is stored into a 2-port memory separately, requiring 4M 2-port memories for each channel. By properly limiting the area formed with the synthetic aperture focusing, the input memory buffer can be implemented with only 4 2-port memories and one short multi-port memory.

• The Korean Journal of Pain
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• 제26권3호
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• pp.249-254
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• 2013

Background: The pes anserine bursa lies beneath the pes anserine tendon, which is the insertional tendon of the sartorius, gracilis, and semitendinosus muscles on the medial side of the tibia, but it can lie in different sites in the medial knee. Accurate diagnosis of the position of the bursa is critical for diagnostic and therapeutic goals. The aim of this study was to evaluate sonoanatomic variations of the pes anserine bursa in the medial knee. Methods: One hundred seventy asymptomatic volunteers were enrolled in this study. Using ultrasound imaging (transverse approach, 7-13 MHz linear array probe) the sonoanatomic position of the pes anserine bursa and its relation to the pes anserine tendon were evaluated. Additionally, we evaluated the sonoanatomic variation of the saphenous nerve. Results: The position of the pes anserine bursa was between the medial collateral ligament and the pes anserine tendons in 21.2%/18.8% (males/females) of subjects; between the pes anserine tendons and the tibia in 67.1%/64.7% (m/f); and among the pes anserine tendons in 8.2%/12.9% (m/f). No significant differences in the position of the bursa existed between males and females. The saphenous nerve was found within the pes anserine tendons in 77.6%/74.1% (m/f) of subjects, but outside the pes anserine tendons in 18.8%/15.3% (m/f). Visibility of sonoanatomic structures was not related to either gender or BMI. Conclusions: Ultrasound provides very accurate information about variations in the pes anserine bursa and the saphenous nerve. This suggests that our proposed ultrasound method can be a reliable guide to facilitate approaches to the medial knee for diagnostic and therapeutic objectives.

• 대한의용생체공학회:의공학회지
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• 제41권1호
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• pp.48-54
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• 2020

In this paper, we deal with a liver fibrosis classification problem using ultrasound B-mode images. Commonly representative methods for classifying the stages of liver fibrosis include liver biopsy and diagnosis based on ultrasound images. The overall liver shape and the smoothness and roughness of speckle pattern represented in ultrasound images are used for determining the fibrosis stages. Although the ultrasound image based classification is used frequently as an alternative or complementary method of the invasive biopsy, it also has the limitations that liver fibrosis stage decision depends on the image quality and the doctor's experience. With the rapid development of deep learning algorithms, several studies using deep learning methods have been carried out for automated liver fibrosis classification and showed superior performance of high accuracy. The performance of those deep learning methods depends closely on the amount of datasets. We propose an enhanced U-net architecture to maximize the classification accuracy with limited small amount of image datasets. U-net is well known as a neural network for fast and precise segmentation of medical images. We design it newly for the purpose of classifying liver fibrosis stages. In order to assess the performance of the proposed architecture, numerical experiments are conducted on a total of 118 ultrasound B-mode images acquired from 78 patients with liver fibrosis symptoms of F0~F4 stages. The experimental results support that the performance of the proposed architecture is much better compared to the transfer learning using the pre-trained model of VGGNet.

• 대한방사선기술학회지:방사선기술과학
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• 제46권4호
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• pp.325-336
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• 2023

The purpose of this study was to analyze the structural relationship between job satisfaction levels felt during ultrasound examination of radiological technologists (RTs) using a structural equation model. The subjects were a total of 203 RTs currently working in medical institutions. The method was conducted as a survey study using a questionnaire consisting of a total of 29 questions consisting of demographic characteristics and job satisfaction levels that were self-efficacy, job competency, extrinsic compensation, and job satisfaction. The reliability was secured with the Cronbach's alpha coefficient of 0.6 or higher. For statistical analysis, a significant difference between the frequency analysis of demographic characteristics and the mean of the job satisfaction levels were performed by independent sample T-test and one-way analysis of variance (ANOVA) followed by Scheffe's post hoc test. The correlation analysis between variables was tested with Spearman's and Pearson's correlation coefficient. We analyzed the structural relationships between variables by structural equations. As a result, first, job competency and extrinsic compensation had a positive effect on job satisfaction on ultrasound examination of RTs. Second, the self-efficacy of ultrasound examination RTs showed a high correlation with job competency. Third, the job satisfaction levels showed in the order of job competency, job satisfaction, self-efficacy, and extrinsic compensation. In conclusion, this study are expected to be provided as data to identify factors that could improve job satisfaction during ultrasound examination of RTs by empirically analyzing the structural relationship of self-efficacy, job competency, and external compensation.

• Journal of Genetic Medicine
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• 제15권2호
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• pp.79-86
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• 2018

Purpose: This study aimed to evaluate the clinical usefulness of non-invasive prenatal testing (NIPT) as an alternative testing of invasive diagnostic testing in pregnancies with ultrasound abnormalities. Materials and Methods: This was a retrospective study of pregnant women with abnormal ultrasound findings before 24 weeks of gestation between April 2016 and March 2017. Abnormal ultrasound findings included isolated increased nuchal translucency, structural anomalies, and soft markers. The NIPT or diagnostic test was conducted and NIPT detected trisomy 21 (T21), T18, T13 and sex chromosomal abnormalities. We analyzed the false positive and residual risks of NIPT based on the ultrasound findings. Results: During the study period, 824 pregnant women had abnormal ultrasound findings. Among the study population, 139 patients (16.9%) underwent NIPT. When NIPT was solely performed in the patients with abnormal ultrasound findings, overall false positive risk was 2.2% and this study found residual risks of NIPT. However, the discordant results of NIPT differed according to the type of abnormal ultrasound findings. Discordant results were significant in the group with structural anomalies with 4.4% false positive rate. However, no discordant results were found in the group with single soft markers. Conclusion: This study found different efficacy of NIPT according to the ultrasound findings. The results emphasize the importance of individualized counseling for prenatal screening or diagnostic test based on the type of abnormal ultrasound.

• 대한수의학회지
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• 제62권1호
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• pp.7.1-7.4
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• 2022

A 7-year-old Scottish Straight cat presented with hypersalivation and generalized hyperesthesia. The cat was provided tuna-based food for 2 to 3 weeks before clinical symptoms appeared. Abdominal ultrasonography showed a heterogeneous, hyperechoic mesentery with hypoechoic foci. Pansteatitis was tentatively diagnosed and the cat was treated with vitamin E, anti-inflammatory drugs, and dietary changes. The clinical signs and changes in mesenteric fat on serial ultrasonography resolved. After feeding tuna-based food again, the same clinical signs and mesenteric changes on ultrasound recurred, which recovered through the same treatment. This study suggests that ultrasonography can be useful for diagnosis and monitoring of feline pansteatitis.

• 전기전자학회논문지
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• 제12권3호
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• pp.158-166
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• 2008

의용 초음파 장비는 X-Ray, CT, MRI 등 다른 의료 장비보다 휴대성과 안전성면에서는 장점이 있지만 진단 시 해상도와 화질 저하를 유발하는 스펙클이 생기는 단점이 있다. 그러나 단순한 스펙클 잡음의 제거는 경계선 정보의 손실을 발생시킬 수도 있다. 이에 본 논문에서는 효과적인 스펙클 제거와 손실 없는 경계선 검출을 위해 뉴럴네트워크와 퍼지 클러스터링을 이용한 뉴로-퍼지 스펙클 제거 방법을 제안하였다. 제안된 방법은 입력된 의용 초음파 영상에 대해 먼저 퍼지 클러스터링을 적용하여 세 영역으로 나누고 이후 각 영역별로 별도의 뉴럴 네트워크를 적용하는 방법이다. 실제 실험 및 기존 방법들과의 정성적?정량적 비교 분석을 통해 제안 방법의 유용성을 검증하였다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권5호
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• pp.579-587
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• 2014

This paper presents a variable gain amplifier (VGA) for an analog front-end (AFE) of ultrasound medical imaging. This VGA has a closed-loop topology and shows a 37-dB-linear characteristic with a single-stage amplifier. It consists of an op-amp, a non-binary-weighted capacitor array, and a gain-control block. This non-binary-weighted capacitor array reduces the required number of capacitors and the complexity of the gain-control block. The VGA has been fabricated in a 0.35-mm CMOS process. This work gives the largest gain range of 37 dB per stage, the largest P1 dB of 9.5 dBm at the 3.3-V among the recent VGA circuits available in the literature. The voltage gain is controlled in the range of [-10, 27] dB in a linear-in-dB scale with 16 steps by a 4-bit digital code. The VGA has a bandpass characteristic with a passband of [20 kHz, 8 MHz].

• 산업공학
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• 제21권4호
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• pp.394-402
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• 2008

The objective of this paper is to design segmentation algorithm for applying the breast ultrasound image to CAD(Computer Aided Diagnosis). This study is conducted after understanding limits, used algorithm and demands of CAD system by interviewing with a medical doctor and analyzing related works based on a general CAD framework that is consisted of five step-establishment of plan, analysis of needs, design, implementation and test & maintenance. Detection function of CAD is accomplished by Canny algorithm and arithmetic operations for segmentation. In addition to, long computing time is solved by extracting ROI (Region Of Interests) and applying segmentation technical methods based morphology algorithm. Overall course of study is conducted by verification of medical doctor. And validity and verification are satisfied by medical doctor's confirmation. Moreover, manual segmentation of related works, restrictions on the number of tumor and dependency of image resolution etc. was solved. This study is utilized as a support system aided doctors' subjective diagnosis even though a lot of future studies is needed for entire application of CAD system.

• Clinics in Shoulder and Elbow
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• 제24권2호
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• pp.93-97
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• 2021

Background: Injection therapy around the distal biceps tendon insertion is challenging. This therapy may be indicated in patients with a partial distal biceps tendon tear, bicipitoradial bursitis and tendinopathy. The primary goal of this study was to determine the accuracy of manually performed injections without ultrasound guidance around the biceps tendon. Methods: Seven upper limb specialists, two general orthopedic specialists, and three orthopedic surgical residents manually injected a cadaver elbow with acrylic dye using an anterior and a lateral infiltration approach. After infiltration the cadaveric elbows were dissected to determine the location of the acrylic dye. Results: In total, 79% of the injections were localized near the biceps tendon. Of these injections, 20% were localized on the radius near the bicipitoradial bursa. In total, 53% of the performed infiltrations were injected by anterior and 47% by lateral approaches. Of the injections near the distal biceps (79%), 47% were injected by an anterior and 53% by a lateral approach. Of the injections on the radius (20%), 33% were injected by anterior and 67% by lateral approach. Of the inaccurate injections (21%), 75% were injected anterior and 25% lateral. Conclusions: Manual infiltration without ultrasound guidance for distal biceps pathology lacks accuracy. We therefore recommend ultrasound guidance for more accurate infiltration.