Time resolved three-dimensional automated segmentation of the left ventricle

Automated segmentation methods are critical for early detection, prompt actions, and immediate treatments in reducing disability and death risks of brain infarction. This paper aims to develop a fully automated method to segment the infarct lesions from T1-weighted brain scans. As a key novelty, the proposed method combines variational mode decomposition and deep learning-based segmentation to take advantages of both methods and provide better results. There are three main technical contributions in this paper. First, variational mode decomposition is applied as a pre-processing to discriminate the infarct lesions from unwanted non-infarct tissues. Second, overlapped patches strategy is proposed to reduce the workload of the deep-learning-based segmentation task. Finally, a three-dimensional U-Net model is developed to perform patch-wise segmentation of infarct lesions. A total of 239 brain scans from a public dataset is utilized to develop and evaluate the proposed method. Empirical results reveal that the proposed automated segmentation can provide promising performances with an average dice similarity coefficient (DSC) of 0.6684, intersection over union (IoU) of 0.5022, and average symmetric surface distance (ASSD) of 0.3932, respectively.

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Picosecond time-resolved photon antibunching measures nanoscale exciton motion and the true number of chromophores

Nature Communications ◽

10.1038/s41467-021-21474-z ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Gordon J. Hedley ◽

Tim Schröder ◽

Florian Steiner ◽

Theresa Eder ◽

Felix J. Hofmann ◽

...

Keyword(s):

Rational Design ◽

Three Dimensional ◽

Dna Origami ◽

Fluorescent Nanoparticles ◽

Time Resolved ◽

Exciton Diffusion ◽

Polymer Aggregates ◽

True Number ◽

Particle Level ◽

Photon Antibunching

AbstractThe particle-like nature of light becomes evident in the photon statistics of fluorescence from single quantum systems as photon antibunching. In multichromophoric systems, exciton diffusion and subsequent annihilation occurs. These processes also yield photon antibunching but cannot be interpreted reliably. Here we develop picosecond time-resolved antibunching to identify and decode such processes. We use this method to measure the true number of chromophores on well-defined multichromophoric DNA-origami structures, and precisely determine the distance-dependent rates of annihilation between excitons. Further, this allows us to measure exciton diffusion in mesoscopic H- and J-type conjugated-polymer aggregates. We distinguish between one-dimensional intra-chain and three-dimensional inter-chain exciton diffusion at different times after excitation and determine the disorder-dependent diffusion lengths. Our method provides a powerful lens through which excitons can be studied at the single-particle level, enabling the rational design of improved excitonic probes such as ultra-bright fluorescent nanoparticles and materials for optoelectronic devices.

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Three-dimensional active shape model matching for left ventricle segmentation in cardiac CT

10.1117/12.481314 ◽

2003 ◽

Cited By ~ 3

Author(s):

Hans C. van Assen ◽

Rob J. van der Geest ◽

Mikhail G. Danilouchkine ◽

Hildo J. Lamb ◽

Johan H. C. Reiber ◽

...

Keyword(s):

Left Ventricle ◽

Cardiac Ct ◽

Three Dimensional ◽

Active Shape Model ◽

Model Matching ◽

Shape Model ◽

Active Shape ◽

Ventricle Segmentation

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Impact of an Aortic Nitinol Stent Graft on Flow Measurements by Time-resolved Three-dimensional Velocity-encoded MRI

Academic Radiology ◽

10.1016/j.acra.2011.10.025 ◽

2012 ◽

Vol 19 (3) ◽

pp. 274-280 ◽

Cited By ~ 3

Author(s):

Fabian Rengier ◽

Michael Delles ◽

Roland Unterhinninghofen ◽

Sebastian Ley ◽

Sasan Partovi ◽

...

Keyword(s):

Stent Graft ◽

Three Dimensional ◽

Flow Measurements ◽

Time Resolved ◽

Nitinol Stent

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Long-term prognostic significance of three-dimensional echocardiographic parameters of the left ventricle and left atrium

European Journal of Echocardiography ◽

10.1093/ejechocard/jep198 ◽

2009 ◽

Vol 11 (3) ◽

pp. 250-256 ◽

Cited By ~ 51

Author(s):

S. Caselli ◽

E. Canali ◽

M. L. Foschi ◽

D. Santini ◽

E. Di Angelantonio ◽

...

Keyword(s):

Left Ventricle ◽

Left Atrium ◽

Prognostic Significance ◽

Three Dimensional ◽

Echocardiographic Parameters

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Automated Segmentation of the Left Ventricle Including Papillary Muscles in Cardiac Magnetic Resonance Images

Functional Imaging and Modeling of the Heart - Lecture Notes in Computer Science ◽

10.1007/978-3-540-72907-5_46 ◽

2007 ◽

pp. 453-462 ◽

Cited By ~ 7

Author(s):

R. El Berbari ◽

I. Bloch ◽

A. Redheuil ◽

E. D. Angelini ◽

E. Mousseaux ◽

...

Keyword(s):

Cardiac Magnetic Resonance ◽

Magnetic Resonance ◽

Left Ventricle ◽

Magnetic Resonance Images ◽

Automated Segmentation ◽

Papillary Muscles

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Effects of Downstream Vane Bowing and Asymmetry on Unsteadiness in a Transonic Turbine

Volume 2A: Turbomachinery ◽

10.1115/gt2018-76735 ◽

2018 ◽

Author(s):

John P. Clark ◽

Richard J. Anthony ◽

Michael K. Ooten ◽

John M. Finnegan ◽

P. Dean Johnson ◽

...

Keyword(s):

Turbine Blades ◽

Three Dimensional ◽

Navier Stokes ◽

Time Resolved ◽

Turbine Engine ◽

Shock Interactions ◽

Design Changes ◽

Post Test ◽

Measured Time ◽

Transonic Turbine

Accurate predictions of unsteady forcing on turbine blades are essential for the avoidance of high-cycle-fatigue issues during turbine engine development. Further, if one can demonstrate that predictions of unsteady interaction in a turbine are accurate, then it becomes possible to anticipate resonant-stress problems and mitigate them through aerodynamic design changes during the development cycle. A successful reduction in unsteady forcing for a transonic turbine with significant shock interactions due to downstream components is presented here. A pair of methods to reduce the unsteadiness was considered and rigorously analyzed using a three-dimensional, time resolved Reynolds-Averaged Navier Stokes (RANS) solver. The first method relied on the physics of shock reflections itself and involved altering the stacking of downstream components to achieve a bowed airfoil. The second method considered was circumferentially-asymmetric vane spacing which is well known to spread the unsteadiness due to vane-blade interaction over a range of frequencies. Both methods of forcing reduction were analyzed separately and predicted to reduce unsteady pressures on the blade as intended. Then, both design changes were implemented together in a transonic turbine experiment and successfully shown to manipulate the blade unsteadiness in keeping with the design-level predictions. This demonstration was accomplished through comparisons of measured time-resolved pressures on the turbine blade to others obtained in a baseline experiment that included neither asymmetric spacing nor bowing of the downstream vane. The measured data were further compared to rigorous post-test simulations of the complete turbine annulus including a bowed downstream vane of non-uniform pitch.

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Blade-Row Interactions in an LP Turbine at Design and Strong Off-Design Operation

Volume 2C: Turbomachinery ◽

10.1115/gt2014-25343 ◽

2014 ◽

Author(s):

Martin Lipfert ◽

Jan Habermann ◽

Martin G. Rose ◽

Stephan Staudacher ◽

Yavuz Guendogdu

Keyword(s):

Experimental Data ◽

Flow Field ◽

Three Dimensional ◽

Suction Side ◽

Test Facility ◽

Time Resolved ◽

Joint Project ◽

Multi Stage ◽

Blade Row ◽

Wake Interactions

In a joint project between the Institute of Aircraft Propulsion Systems (ILA) and MTU Aero Engines a two-stage low pressure turbine is tested at design and strong off-design conditions. The experimental data taken in the altitude test-facility aims to study the effect of positive and negative incidence of the second stator vane. A detailed insight and understanding of the blade row interactions at these regimes is sought. Steady and time-resolved pressure measurements on the airfoil as well as inlet and outlet hot-film traverses at identical Reynolds number are performed for the midspan streamline. The results are compared with unsteady multi-stage CFD predictions. Simulations agree well with the experimental data and allow detailed insights in the time-resolved flow-field. Airfoil pressure field responses are found to increase with positve incidence whereas at negative incidence the magnitude remains unchanged. Different pressure to suction side phasing is observed for the studied regimes. The assessment of unsteady blade forces reveals that changes in unsteady lift are minor compared to changes in axial force components. These increase with increasing positive incidence. The wake-interactions are predominating the blade responses in all regimes. For the positive incidence conditions vane 1 passage vortex fluid is involved in the midspan passage interaction leading to a more distorted three-dimensional flow field.

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Three Dimensional Clocking Effects in a One and a Half Stage Transonic Turbine

Journal of Turbomachinery ◽

10.1115/1.3072715 ◽

2009 ◽

Vol 132 (1) ◽

Cited By ~ 7

Author(s):

O. Schennach ◽

J. Woisetschläger ◽

B. Paradiso ◽

G. Persico ◽

P. Gaetani

Keyword(s):

Flow Field ◽

Three Dimensional ◽

Fast Response ◽

Secondary Flows ◽

Pressure Probe ◽

Time Resolved ◽

Flow Angle ◽

Aerodynamic Pressure ◽

Velocity Flow ◽

Transonic Turbine

This paper presents an experimental investigation of the flow field in a high-pressure transonic turbine with a downstream vane row (1.5 stage machine) concerning the airfoil indexing. The objective is a detailed analysis of the three-dimensional aerodynamics of the second vane for different clocking positions. To give an overview of the time-averaged flow field, five-hole probe measurements were performed upstream and downstream of the second stator. Furthermore in these planes additional unsteady measurements were carried out with laser Doppler velocimetry in order to record rotor phase-resolved velocity, flow angle, and turbulence distributions at two different clocking positions. In the planes upstream of the second vane, the time-resolved pressure field has been measured by means of a fast response aerodynamic pressure probe. This paper shows that the secondary flows of the second vane are significantly modified by the different clocking positions, in connection with the first vane modulation of the rotor secondary flows. An analysis of the performance of the second vane is also carried out, and a 0.6% variation in the second vane loss coefficient has been recorded among the different clocking positions.

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