• The Journal of the Acoustical Society of Korea
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• v.31 no.3
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• pp.151-160
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• 2012

In medical ultrasound imaging, elasticity imaging helps to diagnose tumors such as cancer. This paper is concerned with the application of acoustic radiation force to soft tissue of interest to implement elasticity imaging. In order to reduce the data acquisition time, instead of relying on transmit focusing, a plane wave of burst type is transmitted to apply the acoustic radiation force simultaneously to an entire imaging region to be observed. A homogeneous phantom experiment confirms that increasing the transmit excitation duration instead of employing transmit focusing generates a high enough acoustic radiation force to obtain elasticity images. It is found, however, that a different displacement versus time characteristic is observed unlike the case of using a conventional focused acoustic radiation force. Experimental results obtained through the use of an ultrasound phantom and a bovine liver show that lesions can be correctly differentiated.

• Journal of IKEEE
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• v.26 no.1
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• pp.27-35
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• 2022

This paper proposes an ultrasound vessel-pattern imaging algorithm with low computational complexity. The proposed imaging algorithm reconstructs blood-vessel patterns by only detecting blood flow, and can be applied to a real-time signal processing hardware that extracts an ultrasonic finger-vessel pattern. Unlike a blood-flow imaging mode of typical ultrasound medical imaging device, the proposed imaging algorithm only reconstructs a presence of blood flow as an image. That is, since the proposed algorithm does not use an I/Q demodulation and detects a presence of blood flow by accumulating an absolute value of the clutter-filter output, a structure of the algorithm is relatively simple. To verify a complexity of the proposed algorithm, a simulation model for finger vessel was implemented using Field-II program. Through the behavioral simulation, it was confirmed that the processing time of the proposed algorithm is around 54 times less than that of the typical color-flow mode. Considering the required main building blocks and the amount of computation, the proposed algorithm is simple to implement in hardware such as an FPGA and an ASIC.

• Journal of Medicine and Life Science
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• v.19 no.2
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• pp.70-73
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• 2022

Here, we report a case of ultrasound-assisted subarachnoid block in a patient with severe kyphosis. A 69-year-old man was scheduled for metal removal from hip screws. He had a previous experience with subarachnoid block using the landmark-guided technique, but it was very difficult due to severe kyphosis. However, we could easily determine the correct needle insertion point using ultrasound imaging and performed a successful dural puncture on the first attempt. This case demonstrates the clinical usefulness of ultrasound imaging for subarachnoid blocks in patients with severe kyphosis.

• Korean Journal of Radiology
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• v.23 no.1
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• pp.13-29
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• 2022

Nonalcoholic fatty liver disease, characterized by excessive accumulation of fat in the liver, is the most common chronic liver disease worldwide. The current standard for the detection of hepatic steatosis is liver biopsy; however, it is limited by invasiveness and sampling errors. Accordingly, MR spectroscopy and proton density fat fraction obtained with MRI have been accepted as non-invasive modalities for quantifying hepatic steatosis. Recently, various quantitative ultrasonography techniques have been developed and validated for the quantification of hepatic steatosis. These techniques measure various acoustic parameters, including attenuation coefficient, backscatter coefficient and speckle statistics, speed of sound, and shear wave elastography metrics. In this article, we introduce several representative quantitative ultrasonography techniques and their diagnostic value for the detection of hepatic steatosis.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5799-5804
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• 2014

Background: Radiofrequency ablation (RFA) is the most widely used and studied method internationally for the local treatment of liver tumors. However, the extension of coagulation necrosis in one RFA procedure is limited and incomplete coverage of the damaged area can lead to a high local recurrence rate. Objective: In this study, we compared the effects of different solutions in enhancing hepatic radiofrequency by establishing a rabbit VX2 liver cancer model. We also determined the optimal solution to maximise effects on the extent of RFA-induced coagulation necrosis. Methods: Thirty VX2 tumor rabbits were randomly assigned to five groups: group A, RFA alone; group B, RFA with anhydrous ethanol injection; group C, RFA with 5% hypertonic saline injection; group D, RFA with lidocaine injection; and group E, RFA with a mixed solution. Routine ultrasound examinations and contrast-enhanced ultrasound (CEUS) of the ablation areas were performed after RFA. Then, we measured the major axis and transverse diameter and compared the areas of coagulation necrosis induced by RFA. Results: The mean ablation area range increased in groups B, C and especially E, and the scopes were greater compared with group A. Preoperative application of anhydrous ethanol, hypertonic saline, lidocaine and the mixed solution (groups B, C, D and E, respectively) resulted in larger coagulation necrosis areas than in group A (p<0.05). Among the groups, the coagulation necrosis areas in group E was largest, and the difference was statistically significant compared with other groups (p<0.05). Pathological findings were consistent with imaging results. Conclusions: A mixture of dehydrated alcohol, hypertonic saline and lidocaine injected with RFA increases the extent of coagulation necrosis in the liver with a single application, and the mixed solution is more effective than any other injection alone.

• Journal of Biomedical Engineering Research
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• v.30 no.1
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• pp.66-78
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• 2009

A mobile ultrasound scanner developed for use in point-of-care applications is introduced, which can not only provide ultrasound images but can also measure various bio-signals. The mobile ultrasound scanner is also designed to meet the demanding requirements for point-of-care diagnosis, such as battery-powered operation, portability in terms of size and weigh, and real-time wireless communications capability for remote diagnosis. To meet these requirements, an efficient beamforming method for high resolution imaging with a small number of active elements, a hardware efficient beamformer architecture, and echo processing algorithms with greatly reduced computational complexity have been developed. Experimental results show that the prototype mobile ultrasound scanner is fully functional and satisfies most of the design requirements.

• Journal of Magnetics
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• v.22 no.1
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• pp.55-59
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• 2017

The purpose of this study was to quantitatively evaluate image quality using intensity profile, coefficient of variation (COV), and peak signal to noise ratio (PSNR) with respect to noise reduction techniques in the ultrasound images. For that purpose, we compared with the median filter, Rudin-Osher-Fatemi (ROF), Anscombe and proposed patch group prior based denoising (PGPD) techniques. To evaluate image quality, the Shepp-Logan phantom and the ultrasound image were acquired using simulation and experiment, respectively. According to the results, the difference of intensity profile using PGPD technique is lowest compared with original Shepp-Logan phantom. In simulation, the measured COV was 0.249, 0.198, 0.198, 0.177, and 0.080 using noisy, median, ROF, Anscombe and PGPD technique, respectively. Also, in experimental image, the measured COV was 0.245, 0.230, 0.231, 0.242 and 0.187 using noisy, median, ROF, Anscombe and PGPD technique, respectively. Especially, when we used PGPD technique, the PSNR has highest value in both simulation and experiment. In this study, we performed simulation and experiment study to compare various denoising techniques in the ultrasound image. We can expect the PGPD technique to improve in medical diagnosis with excellent noise reduction.

• Journal of Biomedical Engineering Research
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• v.5 no.1
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• pp.85-92
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• 1984

A new architecture of the Digital Scan Converter (DSC) for the linear-scan ultrasound medical imaging systems is proposed and its hardware implementation is reported. While the conventional DSC merely displays the acquisited data and does nor allow access to the frame memory, it is possible, in the new system, to access to the frame memory for further imaging processing so as to obtain useful information for medical diagnosis. Image processing can be performed either by a special pupose processor, or by VAX 11/780. The system is made to operate asyncronously to increase the frame rate with tags assigned to the data. The proposed DSC was designed to be used without much modification for the sector scan system as well.

• Physical Therapy Rehabilitation Science
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• v.5 no.1
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• pp.47-52
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• 2016

Objective: This study surveyed the perceptions of physical therapists on muscle re-education through visual feedback obtained from rehabilitative ultrasound imaging (RUSI). Design: Survey. Methods: For this study, 500 physical therapists who participated in a refresher training held by the Seoul City Association in March 2015 were selected for a questionnaire-based survey. Subjects were randomly selected targets physiotherapists who participated in a refresher training.The questionnaire had 21 items in total. Questions 1 to 15 could be answered by everyone. However, questions 16 to 21 could be answered only by people who used RUSI. Results: The majority of respondents were aged 20 to 30 years. Respondents in their twenties, thirties, forties, and fifties accounted for 32.4%, 40.2%, 21.9%, and 5.6%respectively. Therapists with careers spanning one to 5 years accounted for 27.8%, while those with careers spanning 5 to 10 years and 10 to 15 years accounted for 34.6% and 17.0%, respectively. Those with careers over 20 years accounted for 9.2%. The types of work have not been various including work related to the nervous system (49.0%), the musculoskeletal system (41.5%), sports (0.7%), juvenile physical therapy (4.2%), and others (4.6%). Conclusions: In this study, we examined the perceptions of physical therapists on rehabilitation ultrasound imaging used in muscle re-education. We also examined how to use this technique. Many therapists who participated in the refresher training were found to be unaware of RUSI. In the future, further investigations on RUSI for muscle re-education are required through refresher training or training lectures at the national level.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.66-71
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• 2014

This paper presents an analog front-end integrated circuit (IC) for medical ultrasound imaging systems using standard $0.18-{\mu}m$ CMOS process. The proposed front-end circuit includes the transmit part which consists of 15-V high-voltage pulser operating at 2.6 MHz, and the receive part which consists of switch and a low-power low-noise preamplifier. Depending on the operation mode, the output driver in the transmit pulser can be reconfigured as the switch in the receive path and thus the area of the overall front-end IC is reduced by over 70% in comparison to previous work. The designed single-channel front-end prototype consumes less than $0.045mm^2$ of core area and can be utilized as a key building block in highly-integrated multi-array ultrasound medical imaging systems.