• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.3
• /
• pp.880-890
• /
• 2010

The intrasvascular ultrasound (IVUS) imaging technique is used to diagnose cerebrovascular diseases such as stroke. Recently, elasticity imaging methods have been investigated to diagnose blood clots attached to blood vessel intima. However, the IVUS imaging technique is an invasive method that requires a transducer to be inserted into blood vessel. In this paper, strain images are obtained of blood clots attached to blood vessel intima with data acquired from outside the blood vessel using a linear array transducer. In order to measure the displacement of blood vessel accurately, experimental data are acquired by steering ultrasound beams so that they can intersect the blood vessel wall at right angles. The acquired rf data are demodulated to the baseband. The resulting complex baseband signals are then processed by an autocorrelation algorithm to compute the blood vessel movement and thereby produce strain image. This proposed method is verified by experiments on a plastic blood vessel mimicking phantom. The efficacy of the proposed method was verified using a home-made blood vessel mimicking phantom. The blood vessel mimicking phantom was constructed by making a 6 mm diameter hollow cylinder inside it to simulate a blood vessel and adhering 2 mm thick soft plaque to the inner wall of the hollow cylinder. The RF data were acquired using a clinical ultrasound scanner (Accuvix XQ, Medison, Seoul. Korea) with a 7.5 MHz linear array transducer by steering ultrasound beams in steps of $1^{\circ}$ from $-40^{\circ}$ to $40^{\circ}$ for a total of 81 angles. Experimental results show that the plaque region near the blood vessel wall is softer than background tissue. Although the imaging region is restricted due to the limited range of angles for which scan lines are perpendicular to the wall, the feasibility of strain imaging is demonstrated.

• Journal of the Korean Society of Radiology
• /
• v.83 no.4
• /
• pp.918-923
• /
• 2022

Large vessel vasculitis is characterized by chronic inflammation within the aortic wall and its major branches. The inflammation is considered to occur as a result of immune dysregulation. Hematologic malignancy is one of the rare causes of secondary vasculitis. Herein, we report a rare case of large vessel vasculitis associated with acute myeloid leukemia mimicking primary vasculitis.

• Advances in pediatric surgery
• /
• v.20 no.2
• /
• pp.58-61
• /
• 2014

Palpable inguinal mass in children should be differentiated from inguinal hernia, hydrocele, lymph node, and tumor. Though using ultrasonography, fatty tumor would be misdiagnosed as incarcerated inguinal hernia containing fatty component. We experienced the huge inguinal lipoblastoma in 5-year-old girl mimicking recurrent incarcerated hernia. Laparoscopic exploration revealed it was not incarcerated hernia but well demarcated bulging mass from abdominal wall. Mass was about $10{\times}4{\times}3cm$ and extended from internal inguinal ring to saphenous opening. It was near total excised because of right external iliac vein injury. Pathologically, it was proven as lipoblastoma containing mature adipocyte with lipoblast and fibrous septa. Postoperatively, we noticed a segmental thrombotic occlusion of external iliac vein. After 1 year, she has no symptom related to occluded vessel. The remained lipoblastoma showed no interval change. Even lipoblastoma has a good prognosis with low recurrence rate, we need careful follow-up.

• Journal of Biomedical Engineering Research
• /
• v.22 no.2
• /
• pp.179-185
• /
• 2001

혈관에 발생하는 동맥 경화증은 그 발생 시기와 진행 정도를 예측하기 힘들어 초기 단계의 진단 및 치료가 어렵다. 이러한 이유로 혈관 질병의 진단은 많은 연구자들의 관심 대상이 되어왔고, 현재까지도 그 진단 장치 및 방법에 관한 연구가 활발히 진행되고 있다. 혈관 벽의 두께 측정은 혈관 질병을 진단할 수 있는 대표적인 지표이다. 그러므로 본 연구는 혈관 벽에서 수신되는 초음파 RF(Radio Frequency) 신호를 wavelet 변환하여 두께를 측정할 수 있는 방법을 제안한다. 시뮬레이션 결과를 토대로 두께가 각각 0.53mm, 1.2mm인 고분자 물질을 가지고 두께측정 실험을 행하였다. 기존의 방법인 주파수 스펙트럼법과 제안한 방법인 wavelet 변환법에 의하여 측정된 평균 두께는 0.53mm인 경우 각각 0.670$\pm$0.168mm(79.10%), 0.448$\pm$0.084mm(84.53%)이고, 1.2mm인 경우 각각 0.962$\pm$0.072mm(80.17%), 1.149$\pm$0.066mm(95.15%)이다. In-vitro 실험을 행하기 위하여 한천, gelatin, SiC 결정을 가지고 두께가 0.85mm인 혈관 유사 시편을 제작하였고, 이 시편으로부터 데이터를 획득하여 이를 제안한 방법으로 두께를 측정하였다. 그 결과 제안한 방법으로 측정된 평균 두께는 0.8008$\pm$0.0154mm(94.22%)이다. 결론적으로 wavelet 변환을 통해서 혈관 벽의 두께를 정밀하게 측정할 수 있는 가능성이 있음을 알 수 있다.

• Design & Manufacturing
• /
• v.15 no.2
• /
• pp.11-16
• /
• 2021

Recently, three-dimensional (3D) cell culture systems, which are superior to conventional two-dimensional (2D) vascular systems that mimic the in vivo environment, are being actively studied to reproduce drug responses and cell differentiation in organisms. Conventional two-dimensional cell culture methods (scaffold-based and non-scaffold-based) have a limited cell growth rate because the culture cannot supply the culture medium as consistently as microvessels. To solve this problem, we would like to propose a 3D culture system with an environment similar to living cells by continuously supplying the culture medium to the bottom of the 3D cell support. The 3D culture system is a structure in which microvascular structures are combined under a scaffold (agar, collagen, etc.) where cells can settle and grow. First, we have manufactured molds for the formation of four types of microvessel-mimicking chips: width / height ①100 ㎛ / 100 ㎛, ②100 ㎛ / 50 ㎛, ③ 150 ㎛ / 100 ㎛, and ④ 200 ㎛ / 100 ㎛. By injection molding, four types of microfluidic chips were made with GPPS (general purpose polystyrene), and a 100㎛-thick PDMS (polydimethylsiloxane) film was attached to the top of each microfluidic chip. As a result of observing the flow of the culture medium in the microchannel, it was confirmed that when the aspect ratio (height/width) of the microchannel is 1.5 or more, the fluid flows from the inlet to the outlet without a backflow phenomenon. In addition, the culture efficiency experiments of colorectal cancer cells (SW490) were performed in a 3D culture system in which PDMS films with different pore diameters (1/25/45 ㎛) were combined on a microfluidic chip. As a result, it was found that the cell growth rate increased up to 1.3 times and the cell death rate decreased by 71% as a result of the 3D culture system having a hole membrane with a diameter of 10 ㎛ or more compared to the conventional commercial. Based on the results of this study, it is possible to expand and build various 3D cell culture systems that can maximize cell culture efficiency by cell type by adjusting the shape of the microchannel, the size of the film hole, and the flow rate of the inlet.

• The Korean Journal of Gastroenterology
• /
• v.72 no.6
• /
• pp.304-307
• /
• 2018

Gastric tuberculosis accounts for approximately 2% of all cases of gastrointestinal tuberculosis. Diagnosis of gastric tuberculosis is challenging because it can present with various clinical, endoscopic, and radiologic features. Tuberculosis manifesting as a gastric subepithelial tumor is exceedingly rare; only several dozen cases have been reported. A 30-year-old male visited emergency room of our hospital with hematemesis and melena. Abdominal CT revealed a 2.5 cm mass in the gastric antrum, and endoscopy revealed a subepithelial mass with a visible vessel at its center on gastric antrum. Primary gastric tuberculosis was diagnosed by surgical wedge resection. We report a rare case of gastric tuberculosis mimicking a subepithelial tumor with acute gastric ulcer bleeding.