• 전기의세계
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• v.28 no.12
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• pp.27-32
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• 1979

13명의 환자에 있어서 새로운 비관혈적 방법에 의한 심박출량을 계산하고, 열희석에 의한 방법으로 측정한 심박출량과 비교하였다. 본 논문에서 사용한 비관혈적 펄스 전달 방법은 대동맥 모델에서의 최적 매개변수 방법을 사용하였다. 모델의 최적 매개변수는 맥압의 첫번째 고주파 전달함수에서 측정치와 계산치의 차이를 최소화하는 조건에 의하여 계산하였다. 전달함수의 2개의 펄스는 각각 경동맥동과 대퇴동맥에서 Piezo-resistive Pulse Microphone을 사용하여 측정하였고, 대동맥의 직경은 초음파 방법을 사용하여 측정하였다. 13명의 환자에게서 16가지 측정을 해서 열희석과 비관혈적 방법은 0.89의 상관계수를 보여주었다.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5245-5247
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• 2014

Background: Helicobacter pylori (H.pylori) is one of the most important causes of dyspepsia and gastric cancer and diagnosis can be made by invasive or non-invasive methods. The Atlas Helicobacter pylori antigen test is a new rapid non-invasive method which is simple to conduct. The aim of this study was to determine its sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy. Materials and Methods: This prospective study was conducted between July 2012 and December 2013. Stool samples of 59 dyspeptic patients who underwent upper endoscopy were evaluated for H. pylori stool antigen. Results: From the 59 patients who participated in this study, there were 36 (61%) males and 23 (39%) females. H. pylori was diagnosed in 24 (40.7%) gastric biopsies, 22 (91.7 %) of these being positive for the Atlas H. pylori antigen test. The sensitivity, specificity, PPV, NPV and accuracy were 91.7%, 100%, 100%, 94.6% and 96.6% respectively. Conclusions: The Atlas H. pylori antigen test is a new non-invasive method which is simple to perform and avails reliable results in a few minutes. Thus it can be the best option for the diagnosis of H. pylori infection due to its high sensitivity and specificity.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.2 s.302
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• pp.33-38
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• 2005

In this paper, the sensing unit of a non-invasive blood glucose sensor for home users, using a magneto-resonance absorption method, have been designed and manufactured. The sensor is capable of non-invasively determining blood glucose levels through measuring the 1H spin-lattice relaxation time in human body, The comparison of initial models, with different dimensions and shapes, for the sensing unit has led us to select the materials of the final model, which has adequate size and weight for home use. Through the design optimization using the FEM model, the dimension of final model has been determined to satisfy the required strength and uniformity of the magnetic field in the detecting area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.9
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• pp.1752-1760
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• 2017

One of the treatments and preventions of strokes such as ischemic stroke is to increase cerebral blood flow. This aims to minimize the size of the stroke by increasing the quantity of blood to the cerebral region circuitously. Several ways to increase cerebral blood flow are a therapy though drugs and through surgery. However these invasive method giving a burden to the patient, the problem of inducing a number of complications were noted. In this thesis, we propose a non-invasive brain flow enhancer to complement the disadvantages of such invasive treatment methods. To compensate for the shortcomings of the existing devices, the patient's blood pressure is accurately measured and the blood pressure is applied to the extremities, thereby increasing blood flow to the femoral region to produce blood clotting treatments. Although somewhat inadequate blood flow increases compared to conventional devices, blood flow can be significantly increased, which can be selectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.171-174
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• 2017

One of the treatments and preventions of strokes such as ischemic stroke is to increase cerebral blood flow. This aims to minimize the size of the stroke by increasing the quantity of blood to the cerebral region circuitously. Several ways to increase cerebral blood flow are a therapy though drugs and through surgery. However these invasive method giving a burden to the patient, the problem of inducing a number of complications were noted. In this thesis, we propose a non-invasive cerebral blood flow augmentation device to compensate for the disadvantages of these invasive treatments. To compensate for the shortcomings of the existing cerebral blood flow device, apply a positive measure of the patient's extremities to measure the blood pressure of the patient's blood pressure and conduct a frontal injection of blood flow to increase blood flow. Although somewhat inadequate blood flow increases compared to conventional devices, blood flow can be significantly increased, which can be selectively.

• Journal of radiological science and technology
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• v.42 no.5
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• pp.345-350
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• 2019

Liver biopsy is the gold standard for diagnosing liver fibrosis, but it is invasive and has a risk for complications. For this reason, recently, study has been actively conducted on non-invasive liver fibrosis evaluation method. But, there is no established standard for the type of diffuse liver disease. Therefore, this study was suggest the usefulness and cut-off values of Fibroscan, FIB-4, APRI and AAR of patients with hepatitis C in Korea. According to the diagnosis, 240 people in hepatitis C are classified into fatty liver, chronic hepatitis, and liver cirrhosis. The statistical analysis was performed by ANOVA to verify difference between groups. The ROC curve was analyzed to determine the usefulness and practical cut-off value. As a result, for all diseases, the AUC value for Fibroscan was 0.8 over and the APRI was 0.7 over. Cut-off value of serum based liver fibrosis markers was increased in order of fatty liver, chronic hepatitis and liver cirrhosis. If Fibroscan and serological liver fibrosis markers are applied to predict liver fibrosis, it is expected that excessive liver biopsy can be reduced.

• Investigative Magnetic Resonance Imaging
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• v.20 no.1
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• pp.36-43
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• 2016

Visualization of the tissue loss tangent property can provide distinct contrast and offer new information related to tissue electrical properties. A method for non-invasive imaging of the electrical loss tangent of tissue using magnetic resonance imaging (MRI) was demonstrated, and the effect of loss tangent was observed through simulations assuming a hyperthermia procedure. For measurement of tissue loss tangent, radiofrequency field maps ($B_1{^+}$ complex map) were acquired using a double-angle actual flip angle imaging MRI sequence. The conductivity and permittivity were estimated from the complex valued $B_1{^+}$ map using Helmholtz equations. Phantom and ex-vivo experiments were then performed. Electromagnetic simulations of hyperthermia were carried out for observation of temperature elevation with respect to loss tangent. Non-invasive imaging of tissue loss tangent via complex valued $B_1{^+}$ mapping using MRI was successfully conducted. Simulation results indicated that loss tangent is a dominant factor in temperature elevation in the high frequency range during hyperthermia. Knowledge of the tissue loss tangent value can be a useful marker for thermotherapy applications.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.12
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• pp.1567-1572
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• 2004

Although accurate measurement of velocity profiles, multiple velocity vectors, and shear stress in arteries is important, there is still no easy method to obtain such information in vivo. This study shows the utility of combining ultrasound contrast imaging with particle image velocimetry (PIV) for non-invasive measurement of velocity vectors. The steady flow analytical solution and optical PIV measurements (for pulsatile flow) were used for comparison. When compared to the analytical solution, both echo PIV and optical PIV resolved the steady velocity profile well. Error in shear rate as measured by echo PIV (8%) was comparable to the error of optical PIV (6.5%). In pulsatile flow, echo PIV velocity profiles agreed well with optical PIV profiles. Echo PIV followed the general profile of pulsatile shear stress across the artery but underestimated wall shear at certain time points. These studies indicate that echo PIV is a promising technique for the non-invasive measurement of velocity profiles and shear stress.

• International Journal of Contents
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• v.9 no.1
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• pp.38-41
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• 2013

The clamp meter maintains electric safety as a non-invasive method while measuring the absolute value of tube current with it has been recently developed for an X-ray high-tension cable. Especially this can show high accuracy at short X-ray exposure time. Considering such a condition, this study is to evaluate the feasibility of a clamp meter in measuring X-ray tube current by taking the measurements and comparing with those of the Dynalyzer III which has been considered as a standard measuring device. From measuring the tube current accuracy depending on changes in tube voltage and exposure time, the clamp meter showed higher accuracy rate which was -1.3~4.2% difference. Thus clamp meter can be used for clinical radiologists who are not familiar electric circuit to manage X-ray devices easily and correctly in the future.

• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.407-412
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• 1997

In this paper, we present a new method to diagnose the characteristics of the soft tissue, especially a liver. In order to diagnose the characteristics of a liver, it is necessary to evaluate the propagation delay time and propagation velocity of bending vibration In a liver. For this purpose, we measure the propagation velocity of bending vibration in a liver for low frequency forced vibration using a standard ultrasonic Doppler diagnosis equipment. We have carried out preliminary experiments by using an ultrasonic probe of 3.5MHz and obtained some results. This new measurement method developed here can be applied to new research and medical fields for acoustic non-invasive diagnosis of soft tissue.