P4A-1 Automated Contour Tracking For High Frame-Rate, Full-View Myocardial Elastography In Vivo

2007 ◽  
Author(s):  
J. Luo ◽  
E. E. Konofagou
Keyword(s):  
Frame Rate ◽  
Contour Tracking ◽  
High Frame Rate ◽  
Full View

Spontaneous Extension Wave for In Vivo Assessment of Arterial Wall Anisotropy

2021 ◽  
Author(s):  
Dan Ran ◽  
Jinping Dong ◽  
He Li ◽  
Wei-Ning Lee
Keyword(s):  
Carotid Artery ◽  
Arterial Wall ◽  
Guided Wave ◽  
Frame Rate ◽  
Mechanical Anisotropy ◽  
Natural Wave ◽  
High Frame Rate ◽  
Longitudinal Stiffness ◽  
Anisotropy Index

Another type of natural wave, traced from longitudinal wall motion and propagation along the artery, is unprecedentedly observed in our in vivo human carotid artery experiments. We coin it as extension wave (EW) and hypothesize that EW velocity (EWV) is associated with arterial longitudinal stiffness. The EW is thus assumed to complement the PW, whose velocity (PWV) is tracked from the radial wall displacement and linked to arterial circumferential stiffness through the Moens-Korteweg equation, as indicators for arterial mechanical anisotropy quantification by noninvasive high-frame-rate ultrasound. The relationship between directional arterial stiffnesses and the two natural wave speeds was investigated in wave theory, finite-element simulations based on isotropic and anisotropic arterial models, and in vivo human common carotid artery (N=10) experiments. Excellent agreement between the theory and simulations showed that EWV was 2.57 and 1.03 times higher than PWV in an isotropic and an anisotropic carotid artery model, respectively, while in vivo EWV was consistently lower than PWV in all 10 healthy human subjects. A strong linear correlation was substantiated in vivo between EWV and arterial longitudinal stiffness quantified by a well-validated vascular guided wave imaging technique (VGWI). We thereby proposed a novel index calculated as EWV2/PWV2 as an alternative to assess arterial mechanical anisotropy. Simulations and in vivo results corroborated the effect of mechanical anisotropy on the propagation of spontaneous waves along the arterial wall. The proposed anisotropy index demonstrated the feasibility of the concurrent EW and PW imaged by high frame-rate ultrasound in grading of arterial wall anisotropy.

Preliminary study on estimation of flow velocity vectors using focused transmit beams

2021 ◽  
Author(s):  
Hideyuki Hasegawa ◽  
Michiya Mozumi ◽  
Masaaki Omura ◽  
Ryo Nagaoka ◽  
Kozue Saito
Keyword(s):  
Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Soft Tissues ◽  
Estimation Error ◽  
Frame Rate ◽  
High Frame Rate ◽  
In Vivo Measurement ◽  
Preliminary Study

Abstract High-frame-rate ultrasound imaging with plane wave transmissions is a predominant method for blood flow imaging, and methods for estimation of blood flow velocity vectors have been developed based on high-frame-rate imaging. On the other hand, in imaging of soft tissues, such as arterial walls and atherosclerotic plaques, high-frame-rate imaging sometimes suffers from high-level clutters. Even in observation of the arterial wall with a focused transmit beam, it would be highly beneficial if blood flow velocity vectors could be estimated simultaneously. We conducted a preliminary study on estimation of blood flow velocity vectors based on a multi-angle Doppler method with focused transmit beam and parallel receive beamforming. It was shown that the lowest estimation error was achieved at a steering angle of 25 degrees by simulation. Also, velocity vectors with typical velocity magnitudes and directions could be obtained by the proposed method in in vivo measurement of a carotid artery.

Intracardiac Vortex Dynamics by High-Frame-Rate Doppler Vortography—In Vivo Comparison With Vector Flow Mapping and 4-D Flow MRI

2017 ◽  
Vol 64 (2) ◽  
pp. 424-432 ◽  
Author(s):  
Julia Faurie ◽  
Mathilde Baudet ◽  
Kondo Claude Assi ◽  
Dominique Auger ◽  
Guillaume Gilbert ◽  
...  
Keyword(s):  
Vortex Dynamics ◽  
Frame Rate ◽  
Flow Mapping ◽  
High Frame Rate ◽  
Vector Flow Mapping ◽  
Flow Mri

scholarly journals In-vivo synthetic aperture and plane wave high frame rate cardiac imaging

2014 ◽  
Author(s):  
Matthias Bo Stuart ◽  
Jonas Jensen ◽  
Andreas Hjelm Brandt ◽  
Svetoslav Ivanov Nikolov ◽  
Michael Bachmann Nielsen ◽  
...  
Keyword(s):  
Plane Wave ◽  
Cardiac Imaging ◽  
Frame Rate ◽  
Synthetic Aperture ◽  
High Frame Rate

scholarly journals In-Vivo Measurement of Dynamic Joint Motion Using High Speed Biplane Radiography and CT: Application to Canine ACL Deficiency

2003 ◽  
Vol 125 (2) ◽  
pp. 238-245 ◽  
Author(s):  
Scott Tashman ◽  
William Anderst
Keyword(s):  
Coordinate System ◽  
High Speed ◽  
Motion Artifacts ◽  
Frame Rate ◽  
Joint Motion ◽  
High Frame Rate ◽  
Flexion Extension ◽  
Standard Deviations ◽  
Skeletal Kinematics

Dynamic assessment of three-dimensional (3D) skeletal kinematics is essential for understanding normal joint function as well as the effects of injury or disease. This paper presents a novel technique for measuring in-vivo skeletal kinematics that combines data collected from high-speed biplane radiography and static computed tomography (CT). The goals of the present study were to demonstrate that highly precise measurements can be obtained during dynamic movement studies employing high frame-rate biplane video-radiography, to develop a method for expressing joint kinematics in an anatomically relevant coordinate system and to demonstrate the application of this technique by calculating canine tibio-femoral kinematics during dynamic motion. The method consists of four components: the generation and acquisition of high frame rate biplane radiographs, identification and 3D tracking of implanted bone markers, CT-based coordinate system determination, and kinematic analysis routines for determining joint motion in anatomically based coordinates. Results from dynamic tracking of markers inserted in a phantom object showed the system bias was insignificant (−0.02 mm). The average precision in tracking implanted markers in-vivo was 0.064 mm for the distance between markers and 0.31° for the angles between markers. Across-trial standard deviations for tibio-femoral translations were similar for all three motion directions, averaging 0.14 mm (range 0.08 to 0.20 mm). Variability in tibio-femoral rotations was more dependent on rotation axis, with across-trial standard deviations averaging 1.71° for flexion/extension, 0.90° for internal/external rotation, and 0.40° for varus/valgus rotation. Advantages of this technique over traditional motion analysis methods include the elimination of skin motion artifacts, improved tracking precision and the ability to present results in a consistent anatomical reference frame.

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