• 제목/요약/키워드: speckle tracking

검색결과 24건 처리시간 0.026초

Two-dimensional speckle-tracking of antral contraction in dogs

  • Park, Junghyun;An, Soyon;Hwang, Tae Sung;Lee, Hee Chun
    • 대한수의학회지
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    • 제60권2호
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    • pp.55-59
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    • 2020
  • This study was purposed to make the referenced range of stomach antral contraction strain in 50 dogs using 2-dimensional speckle tracking. In addition, the strain results were compared among body condition scores to reveal the correlations of obesity among the subjects of the study. Finally, the medetomidine group that was comprised of 10 dogs was compared with the normal group to identify the medetomidine pharmacologic effect in the stomach antral contraction. Clinically healthy 50 dogs were recruited for the study. In an ultrasonographic examination, the stomach antrum region was scanned, and at least one cycle of antral contraction was recorded. The peak strain of antral contraction in healthy dogs was 58.2 ± 20.47% (mean ± SD). The obesity group showed a high strain result and there were significant correlations between the body condition score (BCS) 2, BCS 3 groups and BCS 8 group. The medetomidine group revealed a low strain result and was significantly correlated with normal group. Two-dimensional speckle tracking was useful to the evaluation of stomach motility disorders.

3차원 디지털 스펙클 토모그래피를 이용한 비정상 비대칭 유동의 밀도 분포 재건 (Reconstruction of Density Distribution for Unsteady and Asymmetric Flow Using Three-dimensional Digital Speckle Tomography)

  • 김용재;고한서;백승환
    • 한국가시화정보학회:학술대회논문집
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    • 한국가시화정보학회 2006년도 추계학술대회 논문집
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    • pp.21-24
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    • 2006
  • Transient and asymmetric density distributions have been investigated by a digital speckle tomography with a novel integration method. Multiple CCD images captured movements of speckles in three angles of view simultaneously because the flows were asymmetric and unsteady. The speckle movements which have been formed by a ground glass between no flow and downward butane flow from an elliptical nozzle have been calculated by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays for density gradients. A novel integration method has been developed to obtain projection data from the deflection angles for the speckle tomography. The unsteady density fields have been reconstructed from the accurate projection values by the digital speckle tomography method using the developed integration method.

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개발된 적분법을 포함하는 디지털 스펙클 토모그래피 기법을 이용한 비정상 비대칭 유동 분석 (Analysis of Unsteady and Asymmetric Flows Using Digital Speckle Tomography with Developed Integration Method)

  • 백승환;김용재;고한서
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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    • pp.517-518
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    • 2006
  • Transient and asymmetric density distributions have been investigated by three-dimensional digital speckle tomography with a novel integration method. Multiple CCD images captured movements of speckles in three angles of view simultaneously because the flows were asymmetric and unsteady. The speckle movements which have been formed by a ground glass between no flow and downward butane flow from a circular half opening have been calculated by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays for density gradients. A novel integration method has been developed to obtain projection data from the deflection angles for the speckle tomography.'The three-dimensional density fields have been reconstructed from the accurate projection values by a real-time multiplicative algebraic reconstruction technique (MART) with the developed integration method.

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3차원 실시간 디지털 스페클 토모그래피를 이용한 부탄 밀도 분포 분석 (Analysis of Density Distribution for Butane Using Three-dimentional and Real-time Digital Speckle Tomography)

  • 고한서;박광희;김용재
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.1789-1794
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    • 2003
  • Transient and asymmetric density distributions have been investigated by digital speckle tomography. Multiple CCD images captured movements of speckles in three angles of view simultaneously because the flows were asymmetric and transient. The speckle movements between no flow and downward butane flow from a circular half opening have been calculated by a cross-correlation tracking method so that those distances can be tranferred to deflection angles of laser rays for density gradients. The three-dimensional density fields have been reconstructed from the fringe shift by a real-time multiplicative algebraic reconstruction technique (MART).

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Analysis of Density Distribution for Unsteady Butane Flow Using Three-Dimensional Digital Speckle Tomography

  • Ko, Han-Seo;Park, Kwang-Hee;Kim, Yong-Jae
    • Journal of Mechanical Science and Technology
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    • 제18권7호
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    • pp.1213-1221
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    • 2004
  • Transient and asymmetric density distributions have been investigated by three-dimensional digital speckle tomography. Multiple CCD images captured movements of speckles in three angles of view simultaneously because the flows were asymmetric and transient. The speckle movements between no flow and downward butane flow from a circular half opening have been calculated by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays for density gradients. The three-dimensional density fields have been reconstructed from the deflection angles by a real-time multiplicative algebraic reconstruction technique (MART).

Evaluation of Cardiac Mechanical Dyssynchrony in Heart Failure Patients Using Current Echo-Doppler Modalities

  • Rehab M. Hamdy;Hend Osama;Hanaa M. Fereig
    • Journal of Cardiovascular Imaging
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    • 제30권4호
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    • pp.307-319
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    • 2022
  • BACKGROUND: Current guidelines indicate electrical dyssynchrony as the major criteria for selecting patients for cardiac resynchronization therapy, and 25-35% of patients exhibit unfavorable responses to cardiac resynchronization therapy (CRT). We aimed to evaluate different cardiac mechanical dyssynchrony parameters in heart failure patients using current echo-Doppler modalities and we analyzed their association with electrical dyssynchrony. METHODS: The study included 120 heart failure with reduced ejection fraction (HFrEF) who underwent assessments for left ventricular mechanical dyssynchrony (LVMD) and interventricular mechanical dyssynchrony (IVMD). RESULTS: Patients were classified according to QRS duration: group I with QRS < 120 ms, group II with QRS 120-149 ms, and group III with QRS ≥ 150 ms. Group III had significantly higher IVMD, LVMD indices, TS-SD speckle-tracking echocardiography (STE) 12 segments (standard deviation of time to peak longitudinal strain speckle tracking echocardiography in 12 LV-segments), and LVMD score compared with group I and group II. Group II and group III were classified according to QRS morphology into left bundle branch block (LBBB) and non-LBBB subgroups. LVMD score, TS-SD 12 TDI, and TS-SD 12 STE had good correlations with QRS duration. CONCLUSIONS: HFrEF patients with wide QRS duration (> 150 ms) had more evident LVMD compared with patients with narrow or intermediate QRS. Those patients with intermediate QRS duration (120-150 ms) had substantial LVMD assessed by both TDI and 2D STE, regardless of QRS morphology. Subsequently, we suggest that LVMD indices might be employed as additive criteria to predict CRT response in that patient subgroup. Electrical and mechanical dyssynchrony were strongly correlated in HFrEF patients.

고속 헬륨 제트 유동의 실험적 분석을 위한 4차원 디지털 스펙클 토모그래피 기법 개발 (Development Of Four-Dimensional Digital Speckle Tomography For Experimental Analysis Of High-Speed Helium Jet Flow)

  • 고한서;김용재
    • 한국수소및신에너지학회논문집
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    • 제17권2호
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    • pp.193-203
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    • 2006
  • A high-speed and initial helium jet flow has been analyzed by a developed four-dimensional digital speckle tomography. Multiple high-speed cameras have been used to capture movements of speckles in multiple angles of view simultaneously because a shape of a nozzle for the jet flow is asymmetric and the initial jet flow is fast and unsteady. The speckle movements between no flow and helium jet flow from the asymmetric nozzle controlled by a solenoid valve have been obtained by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays for density gradients. The four-dimensional density fields for the high-speed helium jet flow have been reconstructed from the deflection angles by a developed real-time tomography method.