• Investigative Magnetic Resonance Imaging
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• v.19 no.4
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• pp.241-247
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• 2015

Arteriovenous malformation (AVM) of the pancreas is extremely rare, although it may be increasingly diagnosed due to the widespread use of cross-sectional imaging of the abdomen. Early diagnosis of this disease is important to prevent delay of treatment and resulting fatal complications. We report a rare case of pancreatic AVM in a 48-year-old man who presented with severe chronic anemia and early gastric cancer, which made diagnosis challenging. Imaging findings, including ultrasound, computed tomography, and magnetic resonance imaging, are shown, as well as the pathologic features.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.5
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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].

• Journal of Biomedical Engineering Research
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• v.19 no.3
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• pp.321-325
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• 1998

This paper presents a simple, practical, and efficient method for estimating the speed of sound in reflection mode in ultrasound medical imaging. Its accurate determination is indispensable in order to obtain both good resolution and correct geometrical and volumetric information about human organs such as heart and kidney. Up to now, there have been several methods available, but they all suffer from either poor performance or high complexity. The proposed method finds out an optimum focusing delay profile in such a way that the brightness in a region of interest is maximized using continuous dynamic focusing in receive under fixed transmit focusing. Experiments carried out on a real ultrasound medical phantom reveals that the method a quite simple and effective in providing good speed of sound estimation, hence improved resolution and images, adding to dignostic utility.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.11 no.1
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• pp.21-29
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• 2013

Purpose : The purpose of this study was to determine the changes in ultrasound imaging of the lower limbs in patients with degenerative osteoarthritis who received a total knee replacement (TKR). Methods : The participants for the study were ten patients who were to receive a total knee replacement. Measurements were taken a total of three times: before receiving a total knee replacement, and one week and two weeks after receiving a total knee replacement. The vastus medialis, rectus femoris muscle, tibialis anterior and gastrocnemius muscle were measured using ultrasound imaging. Results : Muscle thickness of the vastus medialis, rectus femoris muscle, tibialis anterior and gastrocnemius muscle had no significant interaction over time whether surgery was performed or not. White area index (WAI) and density of vastus medialis, rectus femoris muscle, tibialis anterior and gastrocnemius muscle had no significant interaction over time whether surgery was performed or not. Conclusion : In conclusion, lower quality muscles were due to a decrease in muscle fiber and an increase in fat fiber. Therefore, initial physical therapy after total knee replacement should consider this point and be designed appropriately as a therapeutic approach for total knee replacement patients.

• Journal of the Korean Orthopaedic Association
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• v.55 no.5
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• pp.426-430
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• 2020

Magnetic resonance imaging and static ultrasound imaging do not indicate some cases of partial thickness tears of the supraspinatus tendon. The authors observed a partial thickness tear of the supraspinatus tendon that was not found using other imaging tools but was observed by resisted scaption in shoulder extension position dynamic ultrasound in several cases. This paper outlines this technique is reported by describing two cases.

• Journal of the Korean Society of Radiology
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• v.8 no.3
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• pp.123-136
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• 2014

In this paper, we study to classify molecular imaging and applications to predict future. Molecular imaging in vivo at the cellular level and the molecular level changes taking place to be imaged, that is molecular cell biology and imaging technology combined with the development of the new field. Molecular imaging is used fluorescence, bioluminescence, SPECT, PET, MRI, Ultrasound and other imaging technologies. That is applied to monitoring of gene therapy, cell tracking and monitoring of cell therapy, antibody imaging, drug development, molecular interaction picture, the near-infrared fluorescence imaging of cancer using fluorescence, bacteria using tumor-targeting imaging, therapeutic early assessment, prediction and therapy. The future of molecular imaging would be developed through fused interdisciplinary research and mutual cooperation, which molecular cell biology, genetics, chemistry, physics, computer science, biomedical engineering, nuclear medicine, radiology, clinical medicine, etc. The advent of molecular imaging will be possible to early diagnosis and personalized treatment of disease in the future.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.148-150
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• 2006

In this paper, the applicability of an UET(ultrasound excited thermography) for a defect detection of the welded receptacle is described. An UET(ultrasound excited thermography) is a defect-selective and fast imaging tool for damage detection. A high power ultrasound-excited vibration energy with pulse durations of 280ms is injected into the outer surface of the welded receptacle made of Al material. An ultrasound vibration energy sent into the welded receptacle propagate inside the sample until they are converted into the heat in the vicinity of the defect. The injection of the ultrasound excited vibration energy results in heat generation so that the defect is turned into a local thermal wave transmitter. Its local heat emission is monitored by the thermal infrared camera. And they are processed by the image recording system. Measurement was performed on aluminum receptacle welded by using Nd:YAG laser. The observed thermal image revealed two area of defects along the welded seam.

• The Journal of the Acoustical Society of Korea
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• v.31 no.8
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• pp.580-589
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• 2012

In this paper, we studied on Doppler gap-filling algorithms suitable for a portable or low-cost medical ultrasound imaging system, and as a result, found out algorithms based on mirroring or autoregressive model. Moreover, controlling the computational demand in the proper range, we improved the performances of these algorithms by solving their problems. Effectiveness of these modified algorithms is verified by computer simulations and experiments which used artificially generated Doppler signals and Doppler data acquired from human body through an actual ultrasound system.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.2
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• pp.231-238
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• 2013

PURPOSE: The purpose of this study is to find out the thickness variation of the superficial and deep abdominal muscles by measuring the thickness of the abdominal muscles. METHODS: 35 young, healthy adults(24 mens and 11 womens) participated in this study. The first, when only bridge exercise we had measured the thickness of their abdominal muscles by the ultrasound. The second, when the abdominal drawing-in during maintaining the bridge exercise we had measured the thickness of their abdominal muscles by the ultrasound. A pared t-test was used to determine a statistical significance for the thickness variation of the superficial and deep abdominal muscles. RESULTS: Results of before and after comparative analysis. The surperficial muscles(rectus abdominis, external obilique) statistically significantly reduced in the thickness and the deep muscle(transeverse abdominis) statistically significantly increased in the thickness. CONCLUSION: We have shown that the abdominal drawing-in exercise during maintaining the bridge exercise was effective to increase in strengthening abdominal deep muscle selectively.

• Journal of Biomedical Engineering Research
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• v.40 no.5
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• pp.179-188
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• 2019

In ultrasound telemedicine, it is important to reduce the size of the data by compressing the ultrasound image when sending it. Ultrasound images can be divided into image context and other information consisting of patient ID, date, and several letters. Between them, ultrasound context is very important information for diagnosis and should be securely preserved as much as possible. In several previous papers, ultrasound compression methods were proposed to compress ultrasound context and other information into different compression parameters. This ultrasound compression method minimized the loss of ultrasound context while greatly compressing other information. This paper proposed the method of automatic segmentation of ultrasound context to overcome the limitation of the previously described ultrasound compression method. This algorithm was designed to robust for various ultrasound device and to enable real-time operation to maintain the benefits of ultrasound imaging machine. The operation time of extracting ultrasound context through the proposed segmentation method was measured, and it took 311.11 ms. In order to optimize the algorithm, the ultrasound context was segmented with down sampled input image. When the resolution of the input image was reduced by half, the computational time was 126.84 ms. When the resolution was reduced by one-third, it took 45.83 ms to segment the ultrasound context. As a result, we verified through experiments that the proposed method works in real time.