Propagation of Vibration Caused by Electrical Excitation in the Normal Human Heart

Kanai, Hiroshi

doi:10.1016/j.ultrasmedbio.2008.12.013

Cited by 89 publications

(59 citation statements)

References 32 publications

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“…This implies that the frame rates reported in Table I can be increased by about 20% when using modified hardware. As such, a 4MLT-4MLA system is capable of imaging the heart at high line density, over a full field-of-view in real-time at frame rates of about 450-500 Hz, which is sufficient to image the electro-mechanical activation of the human heart [19].…”

Section: Discussionmentioning

confidence: 99%

Multi-Transmit Beam Forming for Fast Cardiac Imaging—Experimental Validation and In Vivo Application

Tong

Ramalli

Jasaitytė

et al. 2014

IEEE Trans. Med. Imaging

115

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High frame rate (HFR) echocardiography may be of benefit for functional analysis of the heart. In current clinical equipment, HFR is obtained using multi-line acquisition (MLA) which typically requires broadening of transmit beams. As this may result in a significant degradation of spatial resolution and signal-to-noise ratio (SNR), the capacity of MLA to obtain high quality HFR images remains limited. As an alternative, we have demonstrated by computer simulation that simultaneously transmitting multiple focused beams into different directions [multi-line transmit (MLT)], can increase the frame rate without significantly compromising the spatial resolution or SNR. This study aimed to experimentally verify these theoretical predictions both in vitro and in vivo to demonstrate, for the first time, that cardiac MLT imaging is feasible. Hereto, the ultrasound advanced open platform, equipped with a 2.0 MHz phased array, was programmed to interleave MLT and conventional single line transmit (SLT) beam forming. Using these two beam forming methods, images of phantoms and healthy volunteers were acquired and investigated both qualitatively and quantitatively. The results confirmed our simulations that image quality of a 4MLT imaging system with a Tukey apodization scheme is very competitive to that of SLT while providing a 4 times higher frame rate. It is also demonstrated that MLT can be combined with MLA to provide images at 12- to 16-fold frame rate (about 340-450 Hz) without significantly compromising spatial resolution and SNR. This is thus the first study to demonstrate that this new ultrasound imaging paradigm is viable which could have significant impact on future cardiac ultrasound systems.

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Section: Discussionmentioning

confidence: 99%

Multi-Transmit Beam Forming for Fast Cardiac Imaging—Experimental Validation and In Vivo Application

Tong

Ramalli

Jasaitytė

et al. 2014

IEEE Trans. Med. Imaging

115

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“…These methods enable estimation of regional deformation of the heart wall based on measurements of movement. Although measured strain and strain rate themselves are useful for evaluation of regional myocardial function, it has recently been shown that measurements of transmural transition of myocardial contraction/relaxation and propagation of vibration caused by closure of a heart valve would be useful for evaluation of myocardial function and viscoelasticity [4][5][6]. However, such measurements require a frame rate much higher than that achieved by conventional ultrasonic diagnostic equipment; for example, electrical excitation propagates in Purkinje fibers and ventricular muscle at typical velocities of 0.3-4 m/s [7], and corresponding propagation velocities of myocardial contraction of 0.5-7 m/s were measured by ultrasound [5,8].…”

Section: Introductionmentioning

confidence: 99%

High-frame-rate echocardiography using diverging transmit beams and parallel receive beamforming

2011

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“…In order to appreciate these events a temporal resolution of close to 2 ms would be necessary [1]. In the last decade propagating events have been noted in vivo using different US modalities such as Tissue Doppler Imaging (TDI) and B-mode [2][3][4][5][6][7][8][9][10]. These studies all use velocity curves to describe the electromechanical coupling.…”

Section: Introductionmentioning

confidence: 99%

Feature Tracking Algorithm for Circumferential Strain using High Frame Rate Echocardiography

Andersen

Moore

Schmidt

et al. 2016

2016 Computing in Cardiology Conference (CinC)

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This study aims to describe a feature tracking algorithm tailored to estimate circumferential strain on high frame rate ultrasound (HFR-US) images. The algorithm used the Hungarian assignment algorithm for tracking a basic feature descriptor. A second order Kalman model was used to recursively describe regional myocardial displacement along the myocardial contour, and the strain was calculated using these displacements. HFR-US images at 360 fps were acquired from a patient with left bundle branch block (LBBB) in the parasternal short axis view with a biventricular (BiV) pacer turned off and on. There was a large variation in the onset and end of mechanical contraction for each individual myocardial region when the BiV pacer was turned off. The variation reduced immediately when the BiV pacer was turned on. The presented algorithm can estimate circumferential strain using high frame rate ultrasound images. The circumferential strain does suffer from high intra-and inter-operator variance due to the lack of landmarks making it difficult to reproduce results. However, as circumferential and longitudinal strain offer two different, but somehow interrelated, descriptors of complex mechanical movement of the heart. The observed variance reduction may be indicative for a positive BiV response in LBBB patients.

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Propagation of Vibration Caused by Electrical Excitation in the Normal Human Heart

Cited by 89 publications

References 32 publications

Multi-Transmit Beam Forming for Fast Cardiac Imaging—Experimental Validation and In Vivo Application

Multi-Transmit Beam Forming for Fast Cardiac Imaging—Experimental Validation and In Vivo Application

High-frame-rate echocardiography using diverging transmit beams and parallel receive beamforming

Feature Tracking Algorithm for Circumferential Strain using High Frame Rate Echocardiography

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