• Korean Journal of Radiology
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• v.22 no.3
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• pp.354-365
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• 2021

Objective: To investigate the diagnostic performance of contrast-enhanced ultrasound (CEUS) and its role as a second-line imaging modality after gadoxetate-enhanced MRI (Gd-EOB-MRI) in the diagnosis of hepatocellular carcinoma (HCC) among at risk observations. Materials and Methods: We prospectively enrolled participants at risk of HCC with treatment-naïve solid hepatic observations (≥ 1 cm) of Liver Imaging Reporting and Data System (LR)-3/4/5/M during surveillance and performed Gd-EOB-MRI. A total of one hundred and three participants with 103 hepatic observations (mean size, 28.2 ± 24.5 mm; HCCs [n = 79], non-HCC malignancies [n = 15], benign [n = 9]; diagnosed by pathology [n = 57], or noninvasive method [n = 46]) were included in this study. The participants underwent CEUS with sulfur hexafluoride. Arterial phase hyperenhancement (APHE) and washout on Gd-EOB-MRI and CEUS were evaluated. The distinctive washout in CEUS was defined as mild washout 60 seconds after contrast injection. The diagnostic ability of Gd-EOB-MRI and of CEUS as a second-line modality for HCC were determined according to the European Association for the Study of the Liver (EASL) and the Korean Liver Cancer Association and National Cancer Center (KLCA-NCC) guidelines. The diagnostic abilities of both imaging modalities were compared using the McNemar's test. Results: The sensitivity of CEUS (60.8%) was lower than that of Gd-EOB-MRI (72.2%, p = 0.06 by EASL; 86.1%, p < 0.01 by KLCA-NCC); however, the specificity was 100%. By performing CEUS on the inconclusive observations in Gd-EOB-MRI, HCCs without APHE (n = 10) or washout (n = 12) on Gd-EOB-MRI further presented APHE (80.0%, 8/10) or distinctive washout (66.7%, 8/12) on CEUS, and more HCCs were diagnosed than with Gd-EOB-MRI alone (sensitivity: 72.2% vs. 83.5% by EASL, p < 0.01; 86.1% vs. 91.1% by KCLA-NCC, p = 0.04). There were no false-positive cases for HCC on CEUS. Conclusion: The addition of CEUS to Gd-EOB-MRI as a second-line diagnostic modality increases the frequency of HCC diagnosis without changing the specificities.

• Journal of Biomedical Engineering Research
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• v.31 no.3
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• pp.177-186
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• 2010

In 3D ultrasound color Doppler imaging (CDI), 8-16 pulse transmissions (ensembles) per each scanline are used for effective clutter rejection and flow estimation, but it yields a low volume acquisition rate. In this paper, we have evaluated three flow estimation methods: autoregression (AR), eigendecomposition (ED), and autocorrelation combined with adaptive clutter rejection (AC-ACR) for a small ensemble size (E=4). The performance of AR, ED and AC-ACR methods was compared using 2D and 3D in vivo data acquired under different clutter conditions (common carotid artery, kidney and liver). To evaluate the effectiveness of three methods, receiver operating characteristic (ROC) curves were generated. For 2D kidney in vivo data, the AC-ACR method outperforms the AR and ED methods in terms of the area under the ROC curve (AUC) (0.852 vs. 0.793 and 0.813, respectively). Similarly, the AC-ACR method shows higher AUC values for 2D liver in vivo data compared to the AR and ED methods (0.855 vs. 0.807 and 0.823, respectively). For the common carotid artery data, the AR provides higher AUC values, but it suffers from biased estimates. For 3D in vivo data acquired from a kidney transplant patient, the AC-ACR with E=4 provides an AUC value of 0.799. These in vivo experiment results indicate that the AC-ACR method can provide more robust flow estimates compared to the AR and ED methods with a small ensemble size.

• Korean Journal of Radiology
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• v.20 no.6
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• pp.863-879
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• 2019

Hepatocellular carcinoma (HCC) can be noninvasively diagnosed on the basis of its characteristic imaging findings of arterial phase enhancement and portal/delayed "washout" on computed tomography (CT) and magnetic resonance imaging (MRI) in cirrhotic patients. However, different specific diagnostic criteria have been proposed by several countries and major academic societies. In 2018, major guideline updates were proposed by the Association for the Study of Liver Diseases, European Association for the Study of the Liver (EASL), Korean Liver Cancer Association and National Cancer Center (KLCA-NCC) of Korea. In addition to dynamic CT and MRI using extracellular contrast media, these new guidelines now include magnetic resonance imaging (MRI) using hepatobiliary contrast media as the first-line diagnostic test, while the KLCA-NCC and EASL guidelines also include contrast-enhanced ultrasound (CEUS) as the second-line diagnostic test. Therefore, hepatobiliary MR contrast media and CEUS will be increasingly used for the noninvasive diagnosis and staging of HCC. In this review, we discuss the emerging role of hepatobiliary phase MRI and CEUS for the diagnosis of HCC and also review the changes in the HCC diagnostic criteria in major guidelines, including the KLCA-NCC practice guidelines version 2018. In addition, we aimed to pay particular attention to some remaining issues in the noninvasive diagnosis of HCC.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.2 no.2
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• pp.94-98
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• 2009

Acupuncture is a treatment method that originated more than 3,000 years ago in China and is practiced in most of the world. Acupuncture became the most popular complementary and alternative medicine modality. Ultrasound is useful for research and educational purposes, visualizing needle insertion at acupuncture points, especially next to vulnerable structures such as nerves or the pleura. Additionally, ultrasound is an ideal imaging method for evaluation the biomechanical effects of needle manipulation on tissue and has the distinctive advantage of yielding both images of tissue morphology and biomechanical information. Elastography take aim at quantifying a mechanical response or the mechanical property of tissues from a mechanical stimulus, generated internally or externally. Therefore, the combination of ultrasound and elastography analyses allows quantitative assessment of dynamic changes in the structure of human connective tissue.

• The Journal of the Acoustical Society of Korea
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• v.42 no.5
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• pp.403-411
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• 2023

Functional ultrasound imaging, such as elasticity imaging and micro-blood flow Doppler imaging, enhances diagnostic capability by providing useful mechanical and functional information about tissues. However, the implementation of functional ultrasound imaging poses limitations such as the storage of vast amounts of data in Radio Frequency (RF) data acquisition and processing. In this paper, we propose a sub-Nyquist approach that reduces the amount of acquired axial samples for efficient shear-wave elasticity imaging. The proposed method acquires data at a sampling rate one-third lower than the conventional Nyquist sampling rate and tracks shear-wave signals through RF signals reconstructed using band-pass filtering-based interpolation. In this approach, the RF signal is assumed to have a fractional bandwidth of 67 %. To validate the approach, we reconstruct the shear-wave velocity images using shear-wave tracking data obtained by conventional and proposed approaches, and compare the group velocity, contrast-to-noise ratio, and structural similarity index measurement. We qualitatively and quantitatively demonstrate the potential of sub-Nyquist sampling-based shear-wave elasticity imaging, indicating that our approach could be practically useful in three-dimensional shear-wave elasticity imaging, where a massive amount of ultrasound data is required.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2632-2640
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• 2012

The purpose of this study was to investigate whether medial gastrocnemius ultrasound imaging of the Delayed Onset Muscle Soreness (DOMS) has the possibilities as a measurement method. This study was conducted from April 21th 2011 to April 30th 2011. Thirty-five healthy subjects were included based on the absence of regular physical activity, and no history of recent trauma, musculoskeletal pathology, cardiovascular disease or drug intake. All subjects induced DOMS through climbing for 5 hours and we measured the visual analogue scale (VAS), creatine kinase (CK) and maximal voluntary isometric contraction (MVlC) of ankle plantar flexor prior to DOMS and at 24, 48 and 72 hours post DOMS and these measurements were compared with pennation angle of medial gastrocnemius measured by ultrasound imaging. Results of this study were as following. VAS, CK, and MVIC of ankle plantar flexor were found significant difference related measurement period (p<0.05) and pennation angle of medial gastrocnemius were found significant difference related measurement period (p<0.05). Furthermore, we confirmed that the flow of change between variables related measurment period was consistent. Through this study, we think that measuring the changes in pennation angle of medial gastrocnemius over time using ultrasound imaging will be able to be used as a new method measuring DOMS.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.123-130
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• 2015

This study examines the effects of different types of bridge exercises on the thickness of trunk muscles through ultrasound fusion imaging on 32 students. The thickness of the internal oblique (IO), external oblique (EO), transverse abdominis (TrA), and multifidus (Mf) muscles were measured in three different bridge exercises. The exercises included a supine bridge exercise, which was performed on a fixed support surface (Exercise A), a gym ball bridge exercise (Exercise B), and a sling bridge exercise (Exercise C). There were significant differences among the three bridge exercises in the IO, TrA, and Mf muscles. The IO was thickest in Exercise B followed by Exercise A and C. In contrast, the TrA and the Mf muscles were thickest in Exercise C followed by Exercise A and B. Therefore, the sling bridge exercise may be a more effective method of enhancing trunk muscle thickness than the exercises performed in other positions. Until recently, no previous studies had observed substantial changes in muscle thickness using ultrasound fusion imaging. This study suggests that sling bridge exercises contribute most to the activation of trunk muscles. Therefore, the research can contribute to the prescription and application of bridge exercises in clinical practices.

• Archives of Plastic Surgery
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• v.37 no.4
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• pp.427-432
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• 2010

Purpose: The purpose of this study is to estimate muscle defect by ultrasonography in the patients with secondary deformities of the lip. We investigated the association between the muscle defect in the repaired cleft lip and the philtral appearance not only at resting state but also maximal puckering. Methods: From December 2006 to November 2007, 52 children were evaluated after primary or secondary cheiloplasty. Digital photographs were taken both from the front and both three quarter views in repose and at maximal pucker. Video clips were also taken in repose and at maximal pucker. A panel of four, scored the philtral ridge and dimple seen on these photographs and videos by using two visual analog scales. Eminence of the philtral ridge was scored by a 5 point grading scale, from "conspicuous groove" to "normal philtral ridge" and the philtral dimple was scored by 3 point grading scale, from "no dimple" to "prominent dimple". Ultrasound images of the upper lip were made using a linear array transducer at the resting position of the lip and evaluated by a single radiologist. Results: The philtral ridge eminence scored $2.79{\pm}0.54$ and $1.40{\pm}0.53$ at resting and maximal pucker, correlating with "flat" and "conspicous groove". The philtral dimpling scored $1.44{\pm}0.53$ and $2.27{\pm}0.66$ at resting and maximal pucker, correlating with "no dimple" and "slight dimple". Ultrasound imaging showed the average muscle dehiscence to be $3.78{\pm}2.14$ mm at resting position. Correlation between the muscle defect in ultrasound imaging and philtral ridge eminence at rest was statistically significant (p<0.050), but was not significant (p=0.756) at maximal pucker using Spearman's rank correlation. Correlation between the muscle defect in ultrasound imaging and philtral dimpling was not statistically significant both at rest (p=0.920) and at maximal pucker (p=0.815) using Spearman's rank correlation. Conclusion: Quantitative assessment of the muscle defect using ultrasonography correlates with the static philtral appearance, but does not correlate with the dynamic appearance. Also, the size of the muscle defect does not show any correlation with the philtral dimpling. Our findings reveal that ultrasound imaging partially reflect static appearance of philtrum but cannot reflect dynamic appearance and suggest the need for further research to evaluate dynamic appearance.

• Journal of Veterinary Clinics
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• v.28 no.4
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• pp.408-414
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• 2011

This study was carried out to analyze the utilization of ultrasound machines in animal hospitals and focused on surveying the present condition of diagnostic ultrasound on veterinary medicine in South Korea. Total 279 veterinary hospitals were surveyed with e-mail questionnaires or telephone survey. E-mail questionnaires consist of 17 items of questions including existence of ultrasound machine, types of ultrasound machine, ultrasound examination costs, frequency, purposes, other diagnostic imaging equipments, and referring system of ultrasound. Telephone surveys asked about the existence of the ultrasound machine and types of the ultrasound machine to 279 animal hospitals. Two hundred and seventy-one out of 279 animal hospitals holds ultrasound machine. Seventy-two percents clinics purchased used ultrasonographic machines and mean years after the date of manufacture is 7.5 years and the proportion of superannuated machines are relatively high. Also many clinicians prefer single organ scanning rather than general scan technique and more than 60% of clinics perform ultrasonographic examination less than 5 times a week. Clinics located in Seoul area tend to have more expensive and brand-new ultrasonographic machines and the distribution of radiology specialist are higher in this area. Problems associated with the present condition were oversupply of machines, unequal distribution of the medical equipment in different localities, ineffective use of the medical equipment, and high percentage of old poor-quality medical equipments. There should be a viable alternative proposal to control amount and quality of the ultrasound machines. Also, the improved management system for the ultrasound machine is required.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.516-519
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• 2001

To diagnose a patient's blood vessel disease, apoplexy, hypertension, arteriosclerosis, the blood velocity is very important. Determining the blood velocity methods using ultrasound are Continuous Doppler System and Pulse Doppler System. In using the Pulse Doppler System, we can obtain the position of blood velocity. But it is more complex hardware than Continuous Doppler System and it has low SNR(signal-noise ratio). So in this study, to obtain a believable information we use the Continuous Pulse Doppler System. Thus system have analog part and digital part. In analog part is composed of ultrasound generating part, the amplifying part to amplify the received signal from ultrasound sensor, the demodulation part to detect blood velocity and the filtering part to remove the noise. In digital part is composed of the A/D conversion part, digital signal processing part, and the communication part to communicate the PC. In this study to implement efficient ultrasound blood velocity measurement system, we can get the patient's blood velocity information in realtime. Thus, It is a useful in the accurate diagnosis with C.T(computered tomography), M.R.I(magnetic resonance imaging).