• 한국멀티미디어학회논문지
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• 제24권11호
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• pp.1500-1507
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• 2021

Identification and analysis of the first and second heart sounds(S1, S2) is the easiest way for cardiovascular disease prevention and early diagnosis. However, accurate identification is difficult because the heart sound includes organ movement, blood vortex, user experience, and noise influenced by subjective judgment. Therefore, an algorithm to automatically identify the S1 and S2 heart sounds based on blood vessel transit time(VTT) is presented in this paper. According to the experimental results of comparing the algorithm developed for S1 and S2 heart sound analysis with the conventional Shannon energy algorithm in 10 volunteers, it has been proven that the proposed algorithm can automatically identify S1 and S2 heart sounds with higher accuracy than existing algorithms.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.834-837
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• 2005

In this paper, we describe the method of non-invasive blood pressure measurement using pulse wave transit time(PWTT). PWTT is a new parameter involved with a vascular that can indicate the change of BP. PWTT is measured by continuous monitoring of ECG and pulse wave. No additional sensors or modules are required. In many cases, the change of PWTT correlates with the change of BP. We measure pulse wave using the photo plethysmograph(PPG) sensor in an earlobe and we measure ECG using the ECG monitoring device our made in the chest. The measurement device for detecting pulse wave consists of infrared LED for transmitted light illumination, pin photodiode as light detector, amplifier and filter. We composed 0.5Hz high pass, 60Hz notch and 10Hz low pass filter. ECG measurement device consists of multiplexer, amplifier, filter, micro-controller and RF module. After amplification and filtering, ECG signal and pulse wave is fed through micro-controller. We performed the initial work towards the development of ambulatory BP monitoring system using PWTT. An earlobe is suitable place to measure PPG signal without the restraint in daily work. From the results, we can know that the dependence of PWTT on BP is almost linear and it is possible to monitoring an individual BP continuously after the individual calibration.

• Journal of Trauma and Injury
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• 제28권1호
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• pp.15-20
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• 2015

Purpose: Vascular injuries caused by traffic, industrial accidents and by outside activities have increased in Korea. Especially, vascular injuries to the extremities can lead to limb loss and even mortality if they are not appropriately treated. The aim of the study was to evaluate the surgical outcomes of femoropopliteal vascular management after trauma. Methods: The medical records of 12 patients with femoropopliteal vascular injuries who were treated at Dankook University Hospital from 2011 to 2013 were reviewed. Iatrogenic vascular injuries were excluded. The clinical data including the causes of injury, associated injuries and surgical outcomes were analyzed retrospectively. Results: All patients were male, with a mean age of $46.8{\pm}16.3years$ (range: 26~69 years). The causes of vascular injuries were four traffic accidents, three industrial accidents, two iron plates, one outside activity, one glass injury and one knife injury. The average transit time between the place of the accident place and the emergency department was $3.0{\pm}2.1$ (0.5~12.5) hours, and the average preparation time for surgery was $8.0{\pm}6.7$ (1.7~23.3) hours. The anatomic injuries included the popliteal vessel in seven cases and the femoral vessel in five cases. The average Injury Severity Score (ISS) was $12.0{\pm}5.0$ (5~17), and the average Mangled Extremity Severity Score (MESS) was $5.7{\pm}2.1$ (2~9). The operation methods were four interposition grafts, three end-to-end anastomoses, two direct repairs and three patch angioplasties. One case required amputation of the injured extremity. Conclusion: Early recognition and revascularization of the injured vessel are mandatory to reduce limb loss and to obtain satisfactory outcomes. Therefore, careful/rapid evaluation of the vascular injuries and timely/successful surgical treatment are the keys to salvaging an injured limb.

• 대한의용생체공학회:의공학회지
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• 제30권2호
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• pp.129-134
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• 2009

The ideal method which measures a blood vessel of senility and degree of arteriosclerosis is to measure compliance of arterial and condition of blood circulation at the periphery. In these days vascular stiffness have been assessed by analyzing PTT (pulse transit time) from ECG and PPG. PTT is that between toe and finger each subject estimated through ECG and PPG signals. Two parameters, which are related to PWV, were tested with the time delay between the finger and toe. PWV is a variation of quantity which is associated with vascular stiffness. These researches which use PTT and PWV don't consider the blood vessel characteristic of an individual. In this current research, we have used with the blood vessel characteristic of an individual. That is an assessment of vascular stiffness using the variation of quantity in PWV with the changes of position in the subject. PWV variation increased as functions of the subject's age. The increase of the PWV variation parameters with age is attributed to the direct decrease of the blood vessel compliance with different position. The quantity of variation estimated by experimental results is that old age's (75.78${\pm}$7.75) case is 113.68% and young age's (26.47${\pm}$2.04) case is 85.69%. We proved and presented about estimation of vascular stiffness of possibility by this result.

• Journal of Chest Surgery
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• 제53권3호
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• pp.121-126
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• 2020

Background: The aim of this study was to analyze the clinical outcomes of autogenous brachiocephalic arteriovenous fistulas and to investigate the factors associated with 1-year patency after initiation of hemodialysis. Methods: We retrospectively reviewed the medical records of 41 patients who underwent surgery to create an autogenous brachiocephalic arteriovenous fistula between January 2015 and December 2017, received hemodialysis at the same hospital for longer than 1 year, and were monitored for their vascular access status. Intraoperative flow was measured using transit-time ultrasonography. Results: The 1-year primary and secondary patency rates were 61% (n=25) and 87.8% (n=36), respectively. The functional group (subjects who required no intervention to maintain patency within the first year after hemodialysis initiation) displayed a significantly higher median intraoperative flow rate (450 mL/min) than the non-functional group (subjects who required intervention at least once regardless of 1-year patency) (275 mL/min) (p=0.038). Based on a receiver operating characteristic curve analysis, all patients were additionally subdivided into a high-flow group (>240 mL/min) and a low-flow group (≤240 mL/min). The high-flow group included a significantly greater number of functional brachiocephalic arteriovenous fistulas than the low-flow group (74.2% vs. 20%, respectively; p=0.007). Conclusion: Transit-time flow, as measured with intraoperative transit-time ultrasonography, was associated with patency without the need for intervention at 1 year after initiation of hemodialysis.

• 대한디지털의료영상학회논문지
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• 제12권1호
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• pp.27-31
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• 2010

The purpose of this study was to investigated the usefulness of MR perfusion image comparing with SPECT image. A total of pediatric 30 patients(average age : 7.8) with Moyamoya disease were performed MR Perfusion with 32 channel body coil at 3T from March 01, 2010 to June 10, 2010. The MRI sequences and parameters were as followed : gradient Echo-planar imaging(EPI), TR/TE : 2000ms/50ms, FA : $90^{\circ}$, FOV : $240{\times}240$, Matrix : $128{\times}128$, Thickness : 5mm, Gap : 1.5mm. Images were obtained contrast agent administrated at a rate of 1mL/sec after scan start 10s with a total of slice 1000 images(50 phase/1 slice). It was measured with visual color image and digitize data using MRDx software(IDL version 6.2) and also, it was compared of measurement with values of normal and abnormal ratio to analyze hemodynamic change, and a comparison between perfusion MR with technique using Warm Color at SPECT examination. On MR perfusion examination, the color images from abnormal region to the red collar with rCBV(relative cerebral blood volume) and rCBF(relative cerebral blood flow) caused by increase cerebral blood flow with brain vascular occlusion in surrounding collateral circulation advancement, the blood speed relatively was depicted slowly with blue in MTT(Mean Transit Time) and TTP(Time to Peak) images. The region which was visible abnormally from MR perfusion examination visually were detected as comparison with the same SPECT examination region, would be able to confirm the identical results in MMD(Moyamoya disease)judgments. Hymo-dynamic change in MR perfusion examination produced by increase and delay cerebral blood flow. This change with digitize data and being color imaging makes enable to distinguish between normal and abnormal area. Relatively, MR perfusion examination compared with SPECT examination could bring an excellent image with spatial resolution without radiation expose.

• 대한핵의학회지
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• 제28권3호
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• pp.371-376
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• 1994

저자들은 파파베린유도 음경발기촬영술이 발기부전 원인의 선별검사로서 유용한지를 알아보고자 정상인 12예와 제반검사에서 확진된 동맥성 발기부전 5예, 정맥성 발기부전 12예, 심인성 발기부전 11예, 혼합형 발기부전 8예 및 신경성 발기부전 19예를 대상으로 하여 파파베린의 국소 주사로 발기를 유도하고 $^{99m}Tc$-HSA를 정주하여 관심영역의 시간방사능곡선을 구한 다음 발기유발시간, 발기지속시간 및 정맥성 계수를 비교하였다. 동맥성 발기부전군에서 발기유발시간이 정상 대조군에 비해 지연되어 있었고, 정맥성 발기부전군에서는 정상대조군과 동맥성 발기부전군에 비하여 발기지속시간이 단축되었으며 정맥성계수는 더 낮았다. 심인성 발기부전군에서는 발기지속시간이 정상 대조군 및 동맥성 발기부전군에 비해 지연되어 있었다. 이상의 결과로 파파베린유도 음경발기촬영술은 동맥성과 정맥성 발기부전 뿐만 아니라 심인성 발기부전도 선별할 수 있는 좋은 검사법으로 생각되나 혼합형과 신경성 발기부전을 감별하지 못하는 단점이 있었다.

• Journal of Chest Surgery
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• 제53권5호
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• pp.263-269
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• 2020

Background: The benefits of epicardial ultrasound scanning (EUS) in coronary artery bypass grafting (CABG) have not yet been established. The aim of this study was to evaluate the usefulness of EUS in CABG, including in the assessment of the quality of distal anastomoses, the identification of epicardial target vessels, and the evaluation of any graft issues other than the distal anastomoses. Methods: Fifty-three patients undergoing CABG were enrolled between March 2018 and February 2019. Intraoperative EUS was performed along with transit-time flow measurement (TTFM). Graft evaluations were performed early (shortly after surgery) and 1 year after surgery for 53 (100%) and 47 (88.7%) patients, respectively. Results: EUS was applied to assess the quality of all distal anastomoses, 32 target vessels, and 2 conduit trunks. Insufficient TTFM findings were obtained for 18 grafts. However, graft revision was performed for only 3 distal anastomoses; based on the EUS findings, the remaining 15 sites were not revised. The early and 1-year overall graft patency rates were 100% (141 anastomoses) and 96.1% (122 of 127 anastomoses), respectively. All 15 of the distal anastomoses that were not revised despite insufficient TTFM results were patent at the 1-year mark. Conclusion: The routine application of EUS in CABG could be beneficial by confirming the quality of surgery and reducing unnecessary procedures.

• 대한방사선기술학회지:방사선기술과학
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• 제35권2호
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• pp.165-172
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• 2012

VX2 암종을 이식한 토끼 뇌종양 모델에서, perfusion CT(computed tomography, CT)를 이용하여 종양과 정상 뇌조직의 혈류 특성을 알아보고자 하였다. 체중 2.4~3.0kg(평균 2.6kg)의 토끼(New Zealand white rabbit) 수놈 9마리를 대상으로, 토끼 뇌에 VX2 세포 현탁액 $1{\times}10^7$ cells/ml, 0.1 ml을 이식하고 종양이 5mm 정도 크기로 자라면 perfusion CT를 시행 하였다. GE사의 AW(advantage windows workstation, version 4.2)로 종양의 용적과 perfusion 값을 산출 하였다. 뇌종양의 평균 용적은 $316{\pm}181mm^3$ 이었고, 가장 큰 종양은 497 $mm^3$, 가장 작은 종양은 195 $mm^3$ 이었 이식된 종양 모두 단일 결절형으로 만들어졌고, 두개강 내로 전이는 발견되지 않았다. perfusion CT에서 종양 중심부의 혈류량(cerebral blood volume, CBV)은 $74.40{\pm}9.63$ 이었고, 종양쪽 정상 뇌조직에서는 $16.08{\pm}0.64$ 이었으며, 종양 반대쪽 정상 뇌조직에서는 $15.24{\pm}3.23$이었다. 혈류 속도(cerebral blood flow, CBF)는 종양 중심부에서 $962.91{\pm}75.96$ 이였고, 종양쪽 정상 뇌조직에서는 $357.82{\pm}12.82$ 이었으며, 종양 반대쪽 정상 뇌조직에서는 $323.19{\pm}83.24$ 이었다. 평균 통과시간(mean transit time, MTT)은 종양 중심부에서 $4.37{\pm}0.19$ 이었고, 종양쪽 정상 뇌조직에서는 $3.02{\pm}0.41$ 이었으며, 종양 반대쪽 정상 뇌조직에서는 $2.86{\pm}0.22$ 이었다. 투과성 표면적(permeability surface, PS)은 종양 중심부에서 $47.23{\pm}25.45$ 이었고, 종양쪽 정상 뇌조직에서는 $14.54{\pm}1.60$ 이었으며, 종양 반대쪽 정상 뇌조직에서는 $6.81{\pm}4.20$이었다. 또한, 종양 중심부에서 최고치 도달 시간(time to peak, TTP)은 $19.33{\pm}0.42$ 이었고, 종양쪽 정상 뇌조직에서는 $16.43{\pm}1.72$ 이었으며, 종양 반대쪽 정상 뇌조직에서는 $15.14{\pm}0.88$이었지만 통계적으로 유의하지 않았다. PEI(positive enhancement integral, PEI)은 종양 중심부에서 $61.56{\pm}16.07$ 이었고, 종양쪽 정상 뇌조직에서는 $12.58{\pm}2.61$ 이었으며, 종양 반대쪽 정상 뇌조직에서는 $8.26{\pm}5.55$ 이었다. 최대 증가 기울기(maximum slope of increase, MSI)는 종양 중심부에서 $13.18{\pm}2.81$ 이었고, 종양쪽 정상 뇌조직에서는 $6.99{\pm}1.73$ 이었으며, 종양 반대쪽 정상 뇌조직에서는 $6.41{\pm}1.39$ 이었다. 최대 감소 기울기(maximum slope of decrease, MSD)는 종양 중심부에서 $4.02{\pm}1.37$ 이었고, 종양쪽 정상 뇌조직에서는 $4.66{\pm}0.83$ 이었으며, 종양 반대쪽 정상 뇌조직에서는 $6.47{\pm}1.53$ 으로 나타났다. 결과적으로 정위적(stereotactic)으로 이식된 종양은 단일 결절형으로 두개강 내에 전이가 없어 정상 조직과 종양 조직의 비교 연구에 적합하며, perfusion CT 에서 얻어진 매개 변수(parameter)들은 종양과 정상 조직의 혈관 관류 상태 차이를 잘 반영해 주었다.

• Investigative Magnetic Resonance Imaging
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• 제7권2호
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• pp.116-123
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• 2003

목적 : 가토 모델을 이용한 급성 허혈성 뇌경색에서 확산강조 자기공명영상과 관류자기공명영상의 유용성에 대해 알아보고자 하였다. 대상 및 방법 : 여섯 마리의 순계 가토의 경동맥에 히스토아크릴글루와 리피오돌 및 텅스텐 파우더를 동맥내 주입하여 뇌경색을 유발한 후 1시간 내에 고식적인 T1 및 T2 강조영상, 그리고 확산강조 자기공명영상과 관류자기공명영상을 획득하였다. 관류자기공명영상은 측내실 수준과 대뇌기저핵의 1cm 상방에서 각각 얻었고, 이 영상을 특수 영상 소프트웨어로 후처리하여 뇌혈류 용적 , 뇌혈류양 및 평균 조영제 통과시간을 포함한 관류 영상을 획득하였다. 뇌경색 부위는 각각의 관류 지도와 확산강조 자기공명영상으로 평가하였다. 뇌경색 부위와 반대편 정상 부위에서 조영제 평균 통과시간 차이를 측정하였다. 결과 : 모든 가토에서 T2 강조영상상 비정상 신호강도는 없었으나 확산강조 자기공명영상에서 고신호강도의 뇌경색 병변을 확인할 수 있었다. 상대적 뇌혈류용적, 뇌혈류양 및 평균 조영제 통과시간을 포함한 관류자기공명영상에서 모두 관류 결손을 인지할 수 있었다. 뇌혈류양과 평균 조영제 통과시간 지도에서 관류결손지역으로 나타난 면적의 비교는 6예 중 4예에서 평균 조영제 통과시간 지도가 뇌혈류양 지도보다 면적이 크게 나왔으며, 2예는 같았다. 평균 조영제 통과시간 지도의 관류결손 면적이 뇌혈류양 지도보다 작게 나온 경우는 없었다. 또한 뇌혈류양 지도에서 병변의 면적은 확산강조 자기공명영상에서의 병변의 면적보다 3예에서 넓게 나타났고, 3예에서 같게 나타났다. 평균 조영제 통과시간 지도에서 병변의 면적은 확산강조 자기공명영상에서의 병변의 면적보다 모두 크게 나타났다. 평균 조영제 통과시간 지도에서 병변의 면적이 뇌혈류양 지도에서 병변의 면적보다 크면서 확산강조 자기공명영상에서와 같은 경우가 3예, 뇌혈류양 지도에서 병변의 면적이 확산강조 자기공명영상에서와 같으며 평균 조영제 통과시간 지도에서 병변의 면적보다 작은 경우가 3예, 그리고 평균 조영제 통과시간 지도에서 병변의 면적이 뇌혈류양 지도의 병변의 면적보다 크면서 확산강조 자기공명영상에서의 면적이 가장 적은 경우가 1예 있었다. 결론 : 확산강조 자기공명영상과 관류자기공명영상은 가토에서 초급성 뇌경색을 진단하고 뇌혈류 역학상태를 평가하는데 유용한 기법이라고 생각된다.