• Journal of the Korean Society of Visualization
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• v.3 no.1
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• pp.26-35
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• 2005

The combination of ultrasound echo images with digital particle image velocimetry (DPIV) method has resulted in a two-dimensional, two-component velocity field measurement technique appropriate for opaque flow conditions including blood flow in clinical applications. Advanced PIV processing algorithms including an iterative scheme and window of offsetting were used to increase spatial resolution. The optimum concentration of the ultrasound contrast agent used for seeding was explored. Velocity validation tests in fully developed laminar pipe flow and pulsatile flow showed good agreement with both optical PIV measurements and the known analytic solution. These studies indicate that echo PIV is a promising technique for the non-invasive measurement of velocity profiles and shear stress.

• 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.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.12
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• pp.1528-1534
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• 2004

The combination of ultrasound echo images with digital particle image velocimetry (DPIV) methods has resulted in a two-dimensional, two-component velocity field measurement technique appropriate for opaque flow conditions including blood flow in clinical applications. Advanced PIV processing algorithms including an iterative scheme and window offsetting were used to increase spatial resolution. The optimum concentration of the ultrasound contrast agent used for seeding was explored. Velocity validation tests in fully developed laminar pipe flow result of echo PIV showed good agreement with both optical PIV measurements and the known analytic solution based on a volume flow measurement.

• 순환기질환의공학회:학술대회논문집
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• 2004.11a
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• pp.32-33
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• 2004

• Pediatric Infection and Vaccine
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• v.27 no.2
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• pp.134-139
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• 2020

Staphylococcus epidermidis is a part of the normal skin flora of humans. However, it can cause serious infections in people exposed to foreign bodies or in immunocompromised patients. A 13-year-old boy was hospitalized with fever and myalgia. Painful nodular lesions were detected on the scalp, arms, and legs. Pancytopenia and blasts were present in the peripheral blood. He was diagnosed with acute myeloid leukemia. Magnetic resonance imaging of the whole body showed multiple peripheral rim-enhancing, cyst-like lesions. Ultrasonography showed echogenic nodules inside the cystic lesions in the intramuscular space of the arms and legs. Therefore, cysticercosis was strongly suggested initially. However, an abscess was confirmed on sono-guided biopsy and S. epidermidis was isolated from a microbial culture of the tissue. We report a case of multiple disseminated lesions caused by S. epidermidis in a leukemia patient, initially mistaken for cysticercosis.