• 대한방사선기술학회지:방사선기술과학
• /
• 제32권3호
• /
• pp.299-306
• /
• 2009

MDCT의 시간분해능 향상과 등방성 해상능(isotrophic resolution) 영상의 획득, 그리고 지능적인 심전도 동조를 바탕으로 하여 심혈관 질환의 효과적인 진단검사로 인정받고 있는 후향적 심전도 동조화(retrospective ECG gating) 하의 coronary CT angiography는 상대적으로 많은 환자선량을 제공함으로 인해 우수한 진단방법으로서의 장점을 반감시키고 있다. 이에 각 장치 제조사에서는 환자선량을 감소시키는 방법의 연구가 활성화되어 왔으며, 이의 일환으로 지능적인 cardiac dose modulation 기술과 전향적 심전도 동조화(prospective ECG gating)를 사용한 sequential scan이 도입되고 있다. 이에 본 연구에서는 64 채널 MDCT에서 54 kg, 163 cm인 여성 인체모형팬텀을 대상으로 하고 형광유리선량계를 사용하여 후향적 심전도 동조화 하의 coronary CT angiography 프로토콜에서 환자선량의 정량적 평가와 환자선량 감소를 위해 본원에서 선택적으로 적용하고 있는 5가지 검사 프로토콜을 적용하였을 경우의 effective dose와 중요 부위의 organ dose를 측정 비교하여 다음과 같은 결과를 얻었다. 1) Dose modulation없이 120 kVp와 210 mAs의 노출조건으로 retrospectively ECG gated helical scan으로 시행한 conventional coronary CT angiography 프로토콜의 effective dose는 17.8 mSv였으며, 심장의 organ dose는 103.8 mGy였다. 2) 관전압을 120 kVp에서 100 kVp로 낮추었을 경우 effective dose는 11.0 mSv로 conventional coronary CT에 비해 38.2%가 감소하였으며, 심장은 67.3 mGy로 45.2%가 감소하였다. 3) Cardiac dose modulation을 적용한 경우 effective dose는 13.3 mSv로 conventional coronary CT에 비해 25.3%가 감소하였으며, 심장은 80.0 mGy로 22.9%가 감소하였다. 4) 100 kVp의 저관전압과 cardiac dose modulation을 적용한 경우 effective dose는 8.1 mSv로 conventional coronary CT angiography에 비해 54.5%가 감소하였으며, 심장은 49.5 mGy로 52.3%가 감소하였다.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제18권2호
• /
• pp.181-192
• /
• 2014

In this paper, we propose a robust real-time myocardial border tracking algorithm for echocardiography. Commonly, after an initial contour of LV border is traced at one or two frame from the entire cardiac cycle, LV contour tracking is performed over the remaining frames. Among a variety of tracking techniques, optical flow method is the most widely used for motion estimation of moving objects. However, when echocardiography data is heavily corrupted in some local regions, the errors bring the tracking point out of the endocardial border, resulting in distorted LV contours. This shape distortion often occurs in practice since the data acquisition is affected by ultrasound artifacts, dropout or shadowing phenomena of cardiac walls. The proposed method deals with this shape distortion problem and reflects the motion realistic LV shape by applying global deformation modeled as affine transform partitively to the contour. We partition the tracking points on the contour into a few groups and determine each affine transform governing the motion of the partitioned contour points. To compute the coefficients of each affine transform, we use the least squares method with equality constraints that are given by the relationship between the coefficients and a few contour points showing good tracking results. Many real experiments show that the proposed method supports better performance than existing methods.

• 전자공학회논문지SC
• /
• 제38권5호
• /
• pp.59-69
• /
• 2001

최근에 디지털 선호처리와 전자부품의 발달로 심음 분식에 관한 많은 연구가 진행되고 있다. 그러나 심음 인식, 특히 심음 한주기 전체에 대한 인식연구는 거의 없다. 본 논문에서 심음 전체 한주기에 대한 새로운 인식 방법을 제안하였다. 먼저 주성분 분석을 이용하여 훈련 셋트로 데이터베이스를 구축한다. 데이터베이스는 새로운 심음입력을 인식하는데 이용된다. 심음은 정상심음, 수축전 심잡음, 수축초기 심잡음, 수축 말기 심잡음, 이완 초기 심잡음, 이완 말기 심잡음， 연속적 심잡음으로 분류된다. 실험결과 새로운 인식 방법은 심음의 특징을 인식하는데 효과적이었다. 최대 인식률은 NO의 경우 71%, PS와 ES의 경우 80%, LS의 경우 78%, ED의 경우 87%, LD의 경우 60%, CM의 경우 20% 이었다. 현재의 결과가 실제적으로 심음을 인식하기에는 충분하지 못하였지만 선음 전체 주기를 대상으로 한 연구라는데 의의가 있으며 더 효과적인 데이터베이스를 구축함으로써 인식률을 개선할 수 있다.

• Clinical and Experimental Reproductive Medicine
• /
• 제26권1호
• /
• pp.31-41
• /
• 1999

To evaluate the effectiveness of intrauterine insemination (IUI) in the treatment of infertility, timed-intercourse and intrauterine insemination by husband in stimulated cycles with clomiphene citrate and gonadotropins were compared in a total of 105 cycles. Patients received 100mg of clomiphene citrate daily for 5 days starting on day 3 of the menstrual cycle followed by hMG or FSH. Doses of exogenous gonadotropins were adjusted by the follicular development and concentrations of serum estradiol $(E_2)$. More than 3 follicles reaching >16 mm were present in the ovary, 5,000 IU of hCG was administered intramusculary. Patients received a maximum of three intercourse or IUI cycles for the treatment. Severe male (<$10{\times}10^6$ motile sperm) or age factor (>39 y) patients were excluded in this study. Pregnancy was classified as clinical if a gestational sac or fetal cardiac activity was seen on ultrasound. The overall clinical pregnancy rates were 17.1% per cycle (18/105) and 21.2% per patient (18/85). The pregnancy rates (per cycle) were 17.5% (11/63) in intercourse and 16.7% (7/42) in IUI groups, respectively. IUI had no significant improvement in pregnancy rate compared with timed-intercourse. The multiple pregnancy rates were 11.1% (1 twin and 1 triplet). No patient developed ovarian hyperstimulation. Abortion rate was 28.6% (2/7) in IUI group only. The delivery and ongoing pregnancy rates were 15.2% per cycle (16/105) and 18.8% per patient (16/85). There were no differences in age, duration of infertility, follicle size and level of estradiol $(E_2)$ on the day of hCG injection in pregnant and non-pregnant groups. However, total doses of gonadotropins were higher in pregnant group than in non-pregnant group (p<0.01). Pregnancy rate was not affected by ovulatory status at the time of insemination. These results indicate that well timed-intercourse in stimulated cycles is as effective as IUI for infertile couples.

• Molecules and Cells
• /
• 제45권12호
• /
• pp.923-934
• /
• 2022

Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) have great potential in applications such as regenerative medicine, cardiac disease modeling, and in vitro drug evaluation. However, hPSC-CMs are immature, which limits their applications. During development, the maturation of CMs is accompanied by a decline in their proliferative capacity. This phenomenon suggests that regulating the cell cycle may facilitate the maturation of hPSC-CMs. Aurora kinases are essential kinases that regulate the cell cycle, the role of which is not well studied in hPSC-CM maturation. Here, we demonstrate that CYC116, an inhibitor of Aurora kinases, significantly promotes the maturation of CMs derived from both human embryonic stem cells (H1 and H9) and iPSCs (induced PSCs) (UC013), resulting in increased expression of genes related to cardiomyocyte function, better organization of the sarcomere, increased sarcomere length, increased number of mitochondria, and enhanced physiological function of the cells. In addition, a number of other Aurora kinase inhibitors have also been found to promote the maturation of hPSC-CMs. Our data suggest that blocking aurora kinase activity and regulating cell cycle progression may promote the maturation of hPSC-CMs.

• 대한약침학회지
• /
• 제10권3호
• /
• pp.143-147
• /
• 2007

Objective To derive further studies evaluating the effectiveness of Cultured Wild Ginseng Pharmacopuncture (CWGP) Therapy on squamous cell carcinoma as a first line. Methods Three cycles (4 weeks/cycle) of CWGP were administered as a dosage of 10 ml per day. Patient was diagnosed with stage IIIB squamous cell carcinoma and refused all therapy of conventional medicine because of old age and cardiac invasion of tumor. Intensive treatment of CWGP for 3 cycles was done on the patient. Computed Topography (CT) was performed to evaluate the therapeutic efficacy. Results After the intravenous infusion of 2 cycles of CWGP, chest CT revealed the mass size and pleural invasion sustained stable disease. After the point injection of 1 cycle of CWGP, chest CT revealed progressive disease. The disease free survival rate was 1 month. Conclusion This case may provide us the possibility that CWGP offers potential benefits for patients with squamous cell lung carcinoma. But this is a single case study and further case-series research should be compensated.

• International Journal of Vascular Biomedical Engineering
• /
• 제1권1호
• /
• pp.3-12
• /
• 2003

Ultrasonic pulsed Doppler velocimetry has become a standard international method of classifying carotid disease. Because the measured angle adjusted velocity increases as the Doppler angle increases, examinations should be performed at a convenient standard Doppler examination angle. An angle of 60 degrees is achievable throughout most examinations. Multiple Doppler viewing angles allow the acquisition of velocity vectors during the cardiac cycle, revealing the complex velocity patterns. Ultrasonic velocimetry (whether Doppler or time domain) is based on changes in the phase of the ultrasound echo. Other examinations can be done based on the echo phase. Slow motions of organs such as the brain can be used to monitor changes in edema. Measurements of tissue strain due to the pulsatile filling of the arterioles. This plethysmographic imaging method can display differences in tissue perfusion because of different tissue types and changes in autonomic activity.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권7호
• /
• pp.3275-3279
• /
• 2012

Recently, population-based studies of type 2 diabetes patients have provided evidence that metformin treatment is associated with a reduced cancer incidence and mortality, but its mode of action remains unclear. Here we report effects of metformin on hepatocellular carcinoma (HCC) Hep-G2 cells and details of molecular mechanisms of metformin activity. Our research indicates that metformin displays anticancer activity against HCC through inhibition of the mTOR translational pathway in an AMPK-independent manner, leading to G1 arrest in the cell-cycle and subsequent cell apoptosis through the mitochondrion-dependent pathway. Furthermore, we showed that metformin strongly attenuated colony formation and dramatically inhibited Hep-G2 tumor growth in vivo. In conclusion, our studies suggested that metformin might have potential as a cytotoxic drug in the prevention and treatment of HCC.

• Journal of Chest Surgery
• /
• 제27권2호
• /
• pp.161-165
• /
• 1994

We have experienced a case of ventricular septal defect due to blunt chest trauma. A 22 year old male patient was admitted due to chest pain after Motor cycle accident on July 1st,1993. On 5th hospital day, sudden onset of dyspnea was noted and auscultation represented newly developed systolic murmur. A cardiac catheterization and Left ventriculogram revealed ruptured septum at the apical portion. Because there was open wound on anterior chest wall and congestive heart failure was medically controlled, the patient was discharged for elective operation. He was readmitted on August 14th, 1993.At operation, ventricular septal defect was found in apico-posterior muscular septal area, about 2.0 x 1.5 cm in size. The defect was repaired by double velour patch with interrupted suture and ventriculotomy was closed with Teflon felt. The patient`s postoperative course was uneventful and discharged 10 days postoperatively without complication. The patient have been followed up~ for 2 months. He is on functional class I with small amount of residual shunt at the ventricular septum.

• Journal of Veterinary Science
• /
• 제22권4호
• /
• pp.57.1-57.7
• /
• 2021

In a 3-year-old Samoyed, aortic bulging was found on radiography during a general check-up. On echocardiography, turbulent flow was found in left ventricular outflow tract (LVOT) with high velocity (6.1 m/s). A linear structure was attached to the interventricular septum and connected to the chordae tendineae reaching the papillary muscle. A part of the structure moved during cardiac cycle, similar to mitral motion. This dog was diagnosed with LVOT obstruction caused by accessory mitral valve tissue (AMVT). This is the first report of AMVT in veterinary medicine. AMVT should be considered as a possible cause of LVOT obstruction in dogs.