• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.435-441
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• 2018

In this study, we performed to design an image guiding algorithm to improve the efficiency and safety of treatment of varicose vein by focused ultrasound. The algorithm was suggested by different guiding images according to the location of varicose veins. In the case of deep-seated varicose veins, the target area was marked on the surface of the blood vessel in the obtained cross-sectional blood vessel ultrasound image. In the case of the superficial varicose vein, A guiding system based on image segmentation algorithm of the vascular region was suggested and designed two different algorithms according to varicose veins progression degree. as a results, the algorithm based on ultrasound image show a small error with $830{\mu}m$ at maximum. However, the algorithm based on charge coupled device image has a maximum error of 8.3 mm in some data. Therefore, it is expected that additional study is needed for superficial varicose vein image guiding algorithm, and it is expected that the accuracy of blood vessel tracking should be evaluated by constructing simple system.

• The Journal of the Acoustical Society of Korea
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• v.33 no.5
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• pp.300-308
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• 2014

Photoacoustic imaging is a useful tool for the diagnosis of atherosclerosis because it is capable of providing anatomical and pathological information at the same time. A photoacoustic signal detector is a pivotal element to achieve high spatial resolution, so that it should have broadband spectrum with a high center frequency. Since a photoacoustic imaging probe is directly inserted into blood vessel to diagnose atherosclerosis, the total size of the photoacoustic signal detector should be less than 1 mm. The main purpose of this paper is to demonstrate that PVDF can be used as an active material for the photoacoustic signal detector with a high frequency and broadband characteristic. The photoacoustic signal detector developed in this study was a single element ultrasound transducer with an aperture of $0.5{\times}0.5mm$ and the total size of 1 mm. In the design stage, the natural focal depth was adjusted for an effective focal area to cover the region of interest, i.e., 1~5 mm in depth. This was because geometrical focusing could not be used due to the small aperture. Through a pulse-echo test, it was ascertained that the developed photoacoustic signal detector has the -6 dB bandwidth ranging between 40.1 and 112.8 MHz and the center frequency of 76.83 MHz.

• 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.

• Journal of the Korean Society of Radiology
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• v.79 no.6
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• pp.311-314
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• 2018

Cavernous hemangioma of the breast is a rare benign vascular tumor. It is usually diagnosed as non-palpable mass during imaging examination, incidentally. Common sonographic finding of the breast hemangioma is a superficially located, oval shape, circumscribed margin mass. But the appearance of breast hemangioma is variable and it can be difficult to diagnose in preoperatively. Here, we report a 68-year-old female case with palpable breast mass and increased size on follow up ultrasonography.

• Journal of radiological science and technology
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• v.38 no.4
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• pp.443-449
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• 2015

An ultrasound probe has a big impact on Doppler images even though it has very high risk of frequent function-breakdowns occurring in medical ultrasound scanners. This study experimentally analyses the impacts of an ultrasonic probe's defected elements on power & color Doppler images. The results show that, the bigger the size of defected probe elements is, and the closer a group of action elements is to the center, the more the brightness of images and the velocity of Doppler diminish. When elements' defects increase in color & power Doppler images, false images are formed to be mistaken for blood-vessel plaque in neighboring regions. Accordingly, whenever element defects are suspected, we need check-up process in B-mode. From this respective, it is advisable to have primary interest in a probe and carry out continuous probe QA for ultrasonography.

• Korean Journal of Veterinary Research
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• v.41 no.3
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• pp.413-419
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• 2001

This study was performed to evaluate the renal hemodynamics using color Doppler ultrasonography in dogs with unilateral experimental hydronephrosis treated with transarterial embolization of the renal artery (TAE-RA). Experimental hydronephrosis was induced by ligation of unilateral ureter in 12 dogs. The mean resistive index (RI) value of kidney was significantly increased at 4, 9, 17 days after ligation of ureter. Unilateral hydronephrosis was established in 12 dogs at 17 days after ligation of ureter. Renal artery embolization was performed using selective catheterization in the hydronephrotic kidney of seven dogs and EKG, $SpO_2$body temperature, pulse, and respiratory rate were within normal ranges during procedures. There were no dogs expired after TAE-RA and no side effects associated with regurgitation of iohexol-ethanol solution. In color Doppler ultrasonographic findings, there was no blood flow into the embolized kidneys treated by TAE-RA, however, blood flow signal was found in contralateral normal kidney of dogs treated with TAE-RA compared to that of normal kidney in normal control group. It is concluded that TAE-RA does not affect the hemodynamics of contralateral normal kidney in dogs with experimental hydronephrosis and color Doppler ultrasonography is simple and non-invasive modality for the monitoring of the revascularization of the renal artery after TAE-RA.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.179-182
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• 2004

혈관의 협착으로 인만 혈류의 교란과 그로 인한 초음파 반향의 영향을 튜브에 편심 협착 (eccentric stenosis)을 부착하고 돼지 혈액을 이용해 실험실에서 연구했다. 상용화된 GE LOGIQ 700 Expert 시스템과 M12L 의 선형 트랜스듀서를 이용해 B-모드 영상을 얻은 후 편심 협착 상류 지점과 하류 지점의 초음파 영상을 비교하여 분석하였다. 분당 20 회와 40 회의 박동율과 혈류속도를 바꿔가며 혈류의 교란에 따른 혈액에서의 초음파 영상을 분석한 결과, 편심 협착으로 인한 혈류의 교란으로 적혈구 응집현상이 달라져 복잡한 초음파 반향 분포가 형성되었다. 비침습적 실시간 초음파 영상은 편심 협착으로 인한 혈류의 교란과 그로 인한 혈액의 적혈구 응집 현상을 이해하고 연구하는데 도움이 된다.

• Journal of The Korean Radiological Technologist Association
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• v.28 no.1
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• pp.325-325
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• 2002

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1514-1519
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• 2019

IVUS is an intra-operative imaging modality that facilitates observing and appraising the vessel wall structure of the human coronary arteries. IVUS is regularly used to locate the atherosclerosis lesions in the coronary arteries. Auto-segmentation of the vessel structure is important to detect the disorder of coronary artery. In this paper, we propose a simple strategy to extract Intima/Adventitia area effectively using fuzzy binarization from intravascular images. The proposed method apply fuzzy binarization to find the adventitia but apply average binarization to locate the intima since they have different homogeneity of pixel intensity comparing with the environment. In this paper, we demonstrate an effective auto-segmentation method for detecting the interior/exterior of the vessel walls by differentiating the fuzzy binarization result and average binarization result from IVUS image. Important statistics such as Intima-Media Thickness (IMT) or volume of a target area can be easily computed from result.

• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.935-942
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• 2022

In doing interventional treatment under the guidance of ultrasonography, the medical team detects the legion site with ultrasonic equipment at first, and insert angio needle. In this situation, if the position of legion and the depth of inserted needle on the ultrasonographic screen are different from real position and depth, the needle is likely to damage a major blood vessel or tissue. Accordingly, we had wondered how much such differences between screen image and reality, and so decided to examine them. Using five ultrasonographic equipments manufactured from different companies in different years, this study tried to compare the lengths of the needle on the screen images and real lengths of it, and find out the factors affecting skewness of them. This study used hog meat chunk to mimic human flesh, and sausages as the target of needle. It compared penetrating depths of the needle as the images on the five equipments using single sample t test in the SPSS 22 statistical program. It was found that all the errors were statistically significant(<.05). So, this study decided that it was wrong to evaluate performances of the equipments by the makers and ages of them. It is necessary to do periodic quality controls of equipments and improve the skillfulness of sonographers to reduce error rates between real treatment areas and the images of them.