• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.499-507
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• 2016

Medical imaging techniques such as Magnetic Resonance Imaging (MRI), Computed Tomography (CT) and Ultrasound (US) produce a large amount of digital medical images. Hence, compression of digital images becomes essential and is very much desired in medical applications to solve both storage and transmission problems. But at the same time, an efficient image compression scheme that reduces the size of medical images without sacrificing diagnostic information is required. This paper proposes a novel threshold-based medical image compression algorithm to reduce the size of the medical image without degradation in the diagnostic information. This algorithm discusses a novel type of thresholding to maximize Compression Ratio (CR) without sacrificing diagnostic information. The compression algorithm is designed to get image with high optimum compression efficiency and also with high fidelity, especially for Peak Signal to Noise Ratio (PSNR) greater than or equal to 36 dB. This value of PSNR is chosen because it has been suggested by previous researchers that medical images, if have PSNR from 30 dB to 50 dB, will retain diagnostic information. The compression algorithm utilizes one-level wavelet decomposition with threshold-based coefficient selection.

• Clinical Endoscopy
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• v.57 no.2
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• pp.158-163
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• 2024

Since its development, the use of endoscopic ultrasonography (EUS) in the pancreas and the biliary tract has become increasingly important. The accuracy of EUS varies depending on the experience of the endoscopist. Hence, quality control measures using appropriate indicators are required to reduce these variations. American Society for Gastrointestinal Endoscopy and European Society of Gastrointestinal Endoscopy have announced the EUS quality indicators. Here, we reviewed the quality indicators of the EUS procedure in the current published guidelines.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.4
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• pp.290-298
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• 2014

Ultrasonic thickness measurement is a non-destructive method to measure the local thickness of a solid element, based on the time taken for an ultrasound wave to return to the surface. When an element is very thin, it is difficult to measure thickness with the conventional ultrasonic thickness method. This is because the method measures the time delay by using the peak of a pulse, and the pulses overlap. To solve this problem, we propose a method for measuring thickness by using the power cepstrum and the minimum variance cepstrum. Because the cepstrums processing can divides the ultrasound into an impulse train and transfer function, where the period of the impulse train is the traversal time, the thickness can be measured exactly. To verify the proposed method, we performed experiments with steel and, acrylic plates of variable thickness. The conventional method is not able to estimate the thickness, because of the overlapping pulses. However, the cepstrum ultrasonic signal processing that divides a pulse into an impulse and a transfer function can measure the thickness exactly.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.1 no.1
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• pp.64-72
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• 2008

Compression neuropathy around elbow and wrist are one of the common disturbing problems in the upper extremity. The understanding of normal nerve architectures and pathophysiologic changes in compression neuropathy is important to interpret the ultrasonographic images correctly. Compression neuropathies have characteristic ultrasonographic imaging features of flattened nerve at compression and hypoechoic swollen nerve with loss of fascicular patterns at proximal segments. Dynamic ultrasonographic imagings on motion can show dymanic subluxation of ulnar nerve and medial head of triceps muscle over the medial epicondyle in snapping triceps syndrome. Dynamic compression of median nerve also can be visualized in pronator teres syndrome by dynamic imaging studies. A quantitative measures of cross sectional area or compression ratio can be helpful to diagnose compression neuropathies, such as carpal tunnel syndrome or cubital tunnel syndrome. With the clinical features and electeophysiologic studies, the untrasonographic imagings are useful tool for evaluation of the compression neuropathies in the upper extremities.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.26 no.4
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• pp.318-324
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• 2022

Backgrounds/Aims: Gallstone disease is a recognized complication of bariatric surgery. Subsequent management of choledocholithiasis may be challenging due to altered anatomy which may include Roux-en-Y gastric bypass (RYGB). We conducted a retrospective service evaluation study to assess the safety and efficacy of endoscopic ultrasound-directed transgastric endoscopic retrograde cholangiopancreatography (EDGE) in patients with RYGB anatomy. Methods: All the patients who underwent EDGE for endoscopic retrograde cholangiopancreatography after RYGB at two tertiary care centers in the United Kingdom between January 2020 and October 2021 were included in the study. Clinical and demographic details were recorded for all patients. The primary outcome measures were technical and clinical success. Adverse events were recorded. Hot Axios lumen apposing metal stents measuring 20 mm in diameter and 10 mm in length were used in all the patients for creation of a gastro-gastric or gastro-jejunal fistula. Results: A total of 14 patients underwent EDGE during the study period. The majority of the patients were female (85.7%) and the mean age of patients was 65.8 ± 9.8 years. Technical success was achieved in all but one patient at the first attempt (92.8%) and clinical success was achieved in 100% of the patients. Complications arose in 3 patients with 1 patient experiencing persistent fistula and weight gain. Conclusions: In patients with RYGB anatomy, EDGE facilitated biliary access has a high rate of clinical success with an acceptable safety profile. Adverse events are uncommon and can be managed endoscopically.

• The Journal of the Acoustical Society of Korea
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• v.38 no.4
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• pp.450-458
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• 2019

Passive cavitation imaging method is used to observe the ultrasonic waves generated when a group of bubbles collapses. A problem with passive cavitation imaging is a low resolution and large side lobe levels. Since ultrasound signals generated by passive cavitation take the form of a pulse, the amplitude distribution of signals received across the receive channels varies depending on the direction of incidence. Both the centroid and flatness were calculated to determine weights at imaging points in order to discriminate between the main and side lobe signals from the signal amplitude distribution of the received channel data and to reduce the side lobe levels. The centroid quantifies how the channel data are distributed across the receive channel, and the flatness measures the variance of the channel data. We applied the centroid weight and the flatness to the passive cavitation image constructed using the delay-and-sum focusing and minimum variance beamforming methods to improve the image quality. Using computer simulation and experiment, we show that the application of weighting in delay-and-sum and minimum variance beamforming reduces side lobe levels.

• Physical Therapy Rehabilitation Science
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• v.2 no.2
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• pp.75-80
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• 2013

Objective: The purpose of this study was to examine the effect of cold applied the night before or in the morning on pain and symptoms of plantar fasciitis. Design: Experimental study. Methods: Thirty subjects with plantar fasciitis were recruited for this study. Subjects with plantar fasciitis either had no intervention, cold applied (20 minutes) at night before bed, or 20 minutes in the morning upon wakening. Plantar fascia tenderness and pain were evaluated. There were ten subjects in each group. Measures included visual analog scale, plantar facial thickness via high resolution ultrasound, algometer measure, and range of motion of the ankle and foot. There were 3 groups of 10 subjects, control (no intervention), cold the night before bed, and cold in the morning before rising. Results: The greatest relief of symptoms was cold used at bedtime the night before the measurements. Cold used in the morning was not as effective as cold used in the evening before bed. Cold use reduced the thickness of the plantar fascia and irritation. There was a 13% reduction in plantar fascia thickness with cold the night before (p<0.05), a 44% reduction in pain and an 86 % increase in the force that could be applied to the bottom of the foot without pain (p<0.05). Conclusions: Cold applied for 20 minutes prior bedtime is effective for reduced symptomology caused by plantar fascia inflammation.

• The Korean Journal of Pain
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• v.31 no.2
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• pp.80-86
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• 2018

The Epidural blood patch is considered the gold standard for managing postdural puncture headache when supportive measures fail. However, it is a procedure which can lead to another inadvertent dural puncture. Other potential adverse events that could occur during a blood patch are meningitis, neurological deficits, and unconsciousness. The bilateral greater occipital nerve block has been used for treating chronic headaches in patients with PDPH with a single injection. This minimally invasive, simple procedure can be considered for patients early, along with other supportive treatment, and an epidural blood patch can be avoided.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.4
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• pp.195-203
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• 2012

Dental implants using titanium have greatly advanced through the improvement of designs and surface treatments. Nonetheless, the anatomical limits and physiological changes of the patient are still regarded as obstacles in increasing the success rate of implants further, even with the enhancement of implant products. So there have been many efforts to overcome these limits. The intrinsic potential for bone regeneration can be stimulated through adjuvant treatments with the continuous improvement of implant properties, and this can play an important role in achieving optimum osseointegration toward peripheral bone tissue and securing ultimate long-term implant stability in standard surgical procedures. For this purpose, various chemical, biological, or biophysical measures were developed such as bone grafts, materials, pharmacological agents, growth factors, and bone formation proteins. The biophysical stimulation of bone union includes non-invasive and safe methods. In the beginning, it was developed as a method to enhance the healing of fractures, but later evolved into Pulsed Electromagnetic Field, Low-Intensity Pulsed Ultrasound, and Low-Level Laser Therapy. Their beneficial effects were confirmed in many studies. This study sought to examine bone-implant union and its latest trend as well as the biophysical stimulation method to enhance the union. In particular, this study suggested the enhancement of the function of cells and tissues under a disadvantageous bone metabolism environment through such adjunctive stimulation. This study is expected to serve as a treatment guideline for implant-bone union under unfavorable circumstances caused by systemic diseases hampering bone metabolism or the host environment.

• Structural Engineering and Mechanics
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• v.74 no.5
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• pp.671-678
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• 2020

In this work, the dynamic properties of a high performance concrete containing glass powder (GP) was studied. The GP is a new cementitious material obtained by recycling waste glass presenting pozzolanic activity. This eco-friendly material was incorporated in concrete mixes by replacing 20 and 30% of cement. The mechanical properties of building materials highly affect the response of the structure under dynamic actions. First, the resonant vibration frequencies were measured on concrete plate with free boundary conditions after 14, 28 and 90 curing days by using an alternative vibration monitoring technique. This technique measures the average frequencies of several excitations done at different points of the plate. This approach takes into account the heterogeneity of a material like concrete. So, the results should be more precise and reliable. For measuring the bending and torsion resonant frequencies, as well as the damping ratio. The dynamic properties of material such as dynamic elastic modulus and dynamic shear modulus were determined by modelling the plate on the finite element software ANSYS. Also, the instantaneous aroused frequency method and ultrasound method were used to determine the dynamic elastic modulus for comparison purpose, with the results obtained from vibration monitoring technique.