• Journal of the Korean Society of Visualization
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• v.16 no.1
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• pp.15-20
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• 2018

For the measurement of biophysical properties related with cardiovascular diseases (CVD), various microfluidic devices were proposed. However, many devices were monitored by optical equipment. Ultrasound measurement to quantify the biophysical properties can provide new insights to understand the cardiovascular diseases. This study aims to check feasibility of microfluidic device for ultrasound image analysis based on 3D printer. To facilitate acoustic transmission, agarose solution is poured around 3D mold connected with holes of the acrylic box. By applying speckle image velocimetry(SIV) technique, flow information in the bifurcated channel was estimated. Considering that ultrasound signal amplitude is determined by red blood cell (RBC) aggregation, RBC aggregation in the bifurcated channel can be estimated through the analysis of ultrasound signal. As examples of microfluidic device which mimic the CVD model, velocity fields in microfluidic devices with stenosis and aneurysm were introduced.

• Clinics in Shoulder and Elbow
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• v.27 no.1
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• pp.11-17
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• 2024

Background: Rotator cuff tears are often associated with synovitis, but the ability of noninvasive ultrasonography to predict the severity of synovitis remains unclear. We investigated whether ultrasound parameters, namely peak systolic velocity in the anterior humeral circumflex artery and Doppler activity in the glenohumeral joint and subacromial space, reflect synovitis severity. Methods: A total of 54 patients undergoing arthroscopic rotator cuff repair were selected. Doppler ultrasound was used to measure peak systolic velocity in the anterior humeral circumflex artery and Doppler activity in the glenohumeral joint and subacromial space, and these values were compared with the intraoperative synovitis score in univariate and multivariate analyses. Results: Univariate analyses revealed that tear size, peak systolic velocity in the anterior humeral circumflex artery, and Doppler activity in the glenohumeral joint were associated with synovitis in the glenohumeral joint (P=0.02, P<0.001, P=0.02, respectively). In the subacromial space, tear size, peak systolic velocity in the anterior humeral circumflex artery, and Doppler activity in the subacromial space were associated with synovitis severity (P=0.02, P<0.001, P=0.02, respectively). Multivariate analyses indicated that tear size and peak systolic velocity in the anterior humeral circumflex artery were independently associated with synovitis scores in both the glenohumeral joint and the subacromial space (all P<0.05). Conclusions: These findings demonstrate that tear size and peak systolic velocity in the anterior humeral circumflex artery, which can both be measured noninvasively, are useful indicators of synovitis severity.

• Journal of Biomedical Engineering Research
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• v.29 no.1
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• pp.40-45
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• 2008

Therapeutic ultrasound which is developed for rehabilitation therapy have already been used for healing joint contracture, synechia, acute and chronic inflammatory diseases. Medical devices for pain-relief and healing using therapeutic ultrasound are actively being developed. This study measured the change of PTT with the transmitted ultrasound through the human body to find out the increase of compliance of blood vessels. Measurement method of PTT in this study is employed as useful ways to acquire physiological information of patients in the clinical case in order to measure the change of mechanical characteristics of blood vessels. This study confirmed the PTT change of rehabilitation patients through the thermal effects of ultrasound by using PTT and also found that it is possible to increase PTT by adjusting the warm water and ultrasound. The increase of PTT means the decrease of the pulse wave velocity from the cardiovascular system to the peripheral arteries. The physiological effects occurred using the warm water and ultrasound.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.3
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• pp.389-396
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• 1986

A pulsed ultrasonic doppler flowmeter for mesurements of velocity profils in man is described. The device projects a beam of ultrasound in burst of 570 ns duration at 3.5 MHz. The back-scattered signals are processed to produce a signal oxrresponding to the mean velocity over a small region of the flowing stream. The observation range of 112mm is divided into 128 depth channels. The size of this sample volume determines the flowmeter sensitivity and accuracy. The device uses a quadrature detector to detect the direction of the moving target(hemoglobin). The main feature of the novel instrumnet is its simple hardware structure due to sequential signal processing.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.277-280
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• 2002

In this paper, it is fundamental purpose that finding the relationship between quality and structure of bone, by reconstructing the bone structure image, using ultrasound. In this study, longitudinal transmission method was used for experiment as basic measuring method, which is known as ultrasonic diagnosis method for human tibia. And using ultrasonic velocity parameter that can be detected and calculated with the transmitted signal, new estimated parameter, called Bone Area Fraction, is applied to reconstruct image. Through the in-vitro experiment in cattle's tibia bone, basic sectional image of bone which is similar in real bone structure image can be reconstructed.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.15-18
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• 1995

Three-dimensional steady and pulsatile flow experiments and numerical simulations have conducted to investigate the flow characteristics in the aortic bifurcation model. In vitro velocity measurements were made using both laser Doppler anemometry and pulsed Doppler ultrasound velocimetry. In this study, flow phenomena in the aortic bifurcation model are discussed extensively and the numerical results are compared with experimental results.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.10a
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• pp.207-207
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• 2001

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.4
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• pp.61-68
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• 2006

To measure burning rate of solid propellants using ultrasound, a special closed bomb and an ultrasonic and pressure measurement system are fabricated. During pressurization tests and homing tests on propellants, ultrasonic and pressure signal are acquired in real time fashion by this system. Based on acquired signals, analysis programs using two different algorithm which can measure burning rates corresponding to pressures are compared. One algorithm is to correct sound velocity variation of propellants and solid couplant, another one is only to correct sound velocity variation of propellants. And accuracies of homing rates measured through these algorithms are calculated through comparison with the burning rates measured using strand burner method.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.3
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• pp.153-159
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• 2014

As the number of treatments in the therapeutic ultrasound field targeted at fat tissue increase, the performance of the equipment should be evaluated for safety using a fat phantom. In this study, a fat phantom was fabricated using olive oil and a tissue-mimicking material (TMM) phantom. To evaluate the acoustic properties of the TMM phantom according to the changes in the olive oil, the composition ratio of a liquid mixture of olive oil with a surfactant was adjusted from 5-20% in 5% steps. The acoustic properties of the phantom were evaluated using the sound velocity, attenuation coefficient, density, and acoustic impedance. The experimental results showed that the sound velocity decreased with increasing amount of olive oil but the other acoustic properties did not change. In addition, the phantom using an olive-oil mixture with a 15% composition ratio was most similar to the acoustic characteristics of fat tissue with a sound velocity of 1477.35 m/s, an attenuation coefficient of 0.514 dB/MHz-cm, a density of $1.07g/cm^3$, and an acoustic impedance of 1.575 MRayl. These experimental results are expected contribute to the accuracy of the results using a TMM phantom and will be useful for the therapeutic ultrasound field targeted at subcutaneous fat tissue.

• Proceedings of the Acoustical Society of Korea Conference
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• 1992.06a
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• pp.103-106
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• 1992

기존의 혈류 속도 측정 방법으로는 인체내에 반사 물질을 투입하는 Fick technique과 electromagnetic flowmeter등을 이용한 invasive method와 Ultrasonic Doppler method에 의한 noninvasive method가 이용되고 있다. 이 방법들은 혈과의 모양이나 혈관에서의 flow velocity profile등에 관한 정확한 정보를 얻을 수 없다. 이와같은 문제점들을 해결하기 위한 혈류속도 측정 방법으로 실험실 조건하에서 인체에서와 유사한 혈류측정 장치를 제작하여, vessel의 표본 체적내의 산란체로부터 후방산란되는 초음파 신호의 correlation을 이용한 Ultrasound Time Domain Correlation (UTDC) technique을 연구하였다. UTDC technique을 이용하여 유속을 측정한 결과, 12% 이하의 정밀도로 평균 유체 유속이 측정되었고, Ultrasonic Doppler method에서 측정할 수 없는 혈과의 모양과 혈관의 각 위치에서의 유속 및 혈관벽에 이물질의 존재여부를 명확히 판단할 수 있었다.