• 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.

• The Journal of Korea Robotics Society
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• v.12 no.4
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• pp.395-401
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• 2017

In this paper, we introduce a robot-assisted medical diagnostic system that enables remote ultrasound (US) imaging to be applied to the conventional telemedicine, which has been possible only with interviewing or a visual exam. In particular, a master-slave robot system is developed that ultrasonic diagnosis specialist can control the position and orientation of US probe in the remote place. The slave robot is designed to be compact, lightweight, and hand-held so that it can easily transfer to the remote healthcare center. Moreover, 6-degree-of-freedom (DOF) probe motion is possible by the robot design based on Stewart platform. The master device is also based on a similar structure of the slave robot. To connect master and slave system in the wide area network (WAN) environment, a hardware CODEC was developed. In this paper, we introduce the detail of each component and the results of the recent experiments conducted in the remote sites by the developed robotic ultrasound imaging system.

• Journal of Yeungnam Medical Science
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• v.18 no.2
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• pp.170-186
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• 2001

Musculoskeletal ultrasound (MSUS) has newly evolved by the mechanical improvement of the machine over past several years, becoming a part of imaging techniques for the evaluation of variable diseases in the musculoskeletal system. MSUS has proven diagnostic superiority in pathologies including rotator cuff disease of the shoulder, lateral epicondylitis of the elbow, diseases of the peripheral nerve, detection of intra-articular loose bodies and soft tissue foreign bodies, and in evaluating small superficial soft tissue tumors such as ganglion, epidermoid cyst, and glomus tumor. Besides, MSUS is very useful for obtaining tissue or fluid via percutaneous fine needle aspiration and/or biopsy for the histopathologic diagnosis. Combining MSUS with MR would play a great role in the field of the diagnostic imaging of the musculoskeletal system. The MSUS examiner should have the knowledge of cross-sectional anatomy, and of the mechanical and physical properties of ultrasound in order to interpret the ultrasound findings accurately and properly, and to avoid diagnostic errors due to variable artifacts subsequently. The goal of this article is to introduce the capabilities of MSUS in certain kinds of clinical situation and to familiarize the reader with MSUS. For the purpose, author intends to describe this article according not to the disease-, or organ-based, but to the clinical problem-based format.

• The Journal of the Acoustical Society of Korea
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• v.28 no.1E
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• pp.1-8
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• 2009

Primary radiation force on ultrasound contrast agents (UCA) in a propagating and standing acoustic field was explored. A specific ultrasound contrast agent $Albunex^{(R)}$ and $Optison^{(R)}$ were chosen for simulation. The model was developed based on a shelled bubble model proposed by Church. The numerical simulation suggests that bubble translational motion is more significant in therapeutic ultrasound due to higher intensity and long pulse duration. Even a single cycle of a propagating wave of 4 MPa at 1 MHz can cause a bubble translational motion of greater than $1{\mu}m$ which is approximately one tenth of capillary. Hence, UCA characteristics can be significantly changed in therapeutic ultrasound without rapid bubble collapses.

• Physical Therapy Rehabilitation Science
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• v.10 no.1
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• pp.82-89
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• 2021

Purpose: This study is to investigate the muscle activity based on real-time visual feedback training methods by rehabilitative ultrasound image in elderly and correlation between Heckmatt scale grade, muscle tone and thickness. Design: Cross-sectional study: Pilot study Methods: 6 elderly participated in the study with 2 conditions. Under the condition of rehabilitation ultrasound imaging equipment, all subjects performed voluntary maximal muscle contraction of the quadriceps 3 times using visual feedback based on Rehabilitative Ultrasound Imaging 1.0 (RUSI 1.0). Under the condition of only ultrasound images, all subjects performed voluntary maximal muscle contraction of the quadriceps 3 times using ultrasound image-based visual feedback. The muscle thickness and tone of the quadriceps were measured and the grades were classified by Heckmatt scale and all variables were comparative analyzed. Results: Heckmatt scale grade showed a negative correlation with muscle thickness at relaxation (p<0.05), and a negative correlation with the difference value obtained by subtracting muscle thickness at relaxation from muscle thickness at contraction in ultrasound image condition (p<0.05). The muscle tone during relaxation showed a negative correlation with the muscle thickness during relaxation (p<0.05). Conclusion: In the case of voluntary maximum muscle contraction of the quadriceps muscle in the elderly, it can be seen that the muscle thickness is getting larger when the RUSI 1.0-based visual feedback is provided than with only ultrasound image provided. And the lower Heckmatt scale grade is, the thicker the muscle is, and the lower the muscle tone is.

• Journal of the Korean Society of Physical Medicine
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• v.7 no.3
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• pp.319-327
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• 2012

Purpose : This study aimed to identify the asymmetry observed in the rehabilitative ultrasound imaging of lateral abdominal muscle thickness and performance between the affected and unaffected side during the abdominal drawing-in maneuver (ADIM), an exercise used to facilitate activation of selectively TrA to stabilize the trunk prior to limb movement. Methods : The Participants were twenty one patients with post-stroke hemiplegia in this study. Ultrasound imaging was used to measure amount of changes in thickness of the external oblique (EO), internal oblique (IO), transversus abdominis (TrA). A Paired t-test was used to compare relaxed muscle thickness to contracted muscle thickness of all 3 muscles between the affected and unaffected sides. Results : The outcome measures included side to side differences of absolute thickness, contraction ratio among the lateral abdominal muscles. There was no significantly difference in between the affected and unaffected side at rest. But, there was a significantly difference in absolute muscle thickness between the affected and unaffected side of only TrA muscle. Also contraction ratio was a significantly difference between the affected and unaffected TrA muscle. Conclusion : These findings support the asymmetrical activation of TrA muscle during abdominal muscle contraction in patients with post-stroke hemiplegia. Further studies are warranted for confirming this outcome.

• Journal of Biomedical Engineering Research
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• v.44 no.4
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• pp.255-263
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• 2023

Clinical ultrasound (US) is a widely used imaging modality with various clinical applications. However, capturing a large field of view often requires specialized transducers which have limitations for specific clinical scenarios. Panoramic imaging offers an alternative approach by sequentially aligning image sections acquired from freehand sweeps using a standard transducer. To reconstruct a 3D volume from these 2D sections, an external device can be employed to track the transducer's motion accurately. However, the presence of optical or electrical interferences in a clinical setting often leads to incorrect measurements from such sensors. In this paper, we propose a deep learning (DL) framework that enables the prediction of scan trajectories using only US data, eliminating the need for an external tracking device. Our approach incorporates diverse data types, including correlation volume, optical flow, B-mode images, and rawer data (IQ data). We develop a DL network capable of effectively handling these data types and introduce an attention technique to emphasize crucial local areas for precise trajectory prediction. Through extensive experimentation, we demonstrate the superiority of our proposed method over other DL-based approaches in terms of long trajectory prediction performance. Our findings highlight the potential of employing DL techniques for trajectory estimation in clinical ultrasound, offering a promising alternative for panoramic imaging.

• The Journal of the Acoustical Society of Korea
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• v.29 no.8
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• pp.504-508
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• 2010

In conventional diagnostic ultrasound strain imaging, when displaying strain image on a monitor, human visual characteristics are utilized such that hard regions are displayed as dark and soft regions are displayed as bright. Thus, hard regions representing tumor or cancer are displayed as dark, decreasing the contrast inside the lesion. Because the lesion area is stiff and thus displayed as dark, a method of inverting the image brightness and thereby increasing the contrast in the lesion for better diagnostic purposes is proposed wherein a postcompression signal is extended in the time domain by a factor corresponding to the reciprocal of the amount of the applied compression using a technique termed globally uniform stretching. Experiments were carried out to verify the proposed method on an ultrasound elasticity phantom with radio-frequency data acquired from a diagnostic ultrasound clinical scanner. It is found that the new method improves the contrast-to-noise ratio by a factor of up to about 1.8 compared to a conventional strain imaging method that employs a reversed gray color map without globally uniform stretching.

• Korean Journal of Radiology
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• v.21 no.11
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• pp.1210-1219
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• 2020

Objective: To compare the utility and diagnostic performance of automated breast ultrasound system (ABUS) with that of handheld ultrasound (HHUS) in evaluating pure non-mass enhancement (NME) lesions on breast magnetic resonance imaging (MRI). Materials and Methods: One hundred twenty-six consecutive MRI-visible pure NME lesions of 122 patients with breast cancer were assessed from April 2016 to March 2017. Two radiologists reviewed the preoperative breast MRI, ABUS, and HHUS images along with mammography (MG) findings. The NME correlation rate and diagnostic performance of ABUS were compared with that of HHUS, and the imaging features associated with ABUS visibility were analyzed. Results: Among 126 pure NME lesions, 100 (79.4%) were malignant and 26 (20.6%) were benign. The overall correlation rate was 87.3% (110/126) in ABUS and 92.9% (117/126) in HHUS. The sensitivity and specificity were 87% and 50% for ABUS and 92% and 42.3% for HHUS, respectively, with no significant differences (p = 0.180 and 0.727, respectively). Malignant NME was more frequently visualized than benign NME lesions on ABUS (93% vs. 65.4%, p = 0.001). Significant factors associated with the visibility of ABUS were the size of NME lesions on MRI (p < 0.001), their distribution pattern (p < 0.001), and microcalcifications on MG (p = 0.027). Conclusion: ABUS evaluation of pure NME lesions on MRI in patients with breast cancer is a useful technique with high visibility, especially in malignant lesions. The diagnostic performance of ABUS was comparable with that of conventional HHUS in evaluating NME lesions.