Louise Allard

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This work explores the potential of shear strain elastograms to identify vulnerable atherosclerotic plaques. The Lagrangian speckle model estimator (LSME) elasticity imaging method was further developed to estimate shear strain elasticity (SSE). Three polyvinyl alcohol cryogel vessel phantoms were imaged with an intravascular ultrasound (IVUS) scanner. The(More)
The paper describes the design, training and testing of a three-layer feedforward back-propagation neural network for the classification of bioprosthetic valve closure sounds. Forty-seven patients with a porcine bioprosthetic valve inserted in the aortic position were involved in the study. Twenty-four of them had a normal bioprosthetic valve, and the other(More)
Blood turbulence downstream of a concentric 86 percent area reduction stenosis was characterized using absolute and relative Doppler spectral broadening measurements, relative Doppler velocity fluctuation, and Doppler backscattered power. Bidimensional mappings of each Doppler index were obtained using a 10 MHz pulsed-wave Doppler system. Calf red cells(More)
PURPOSE The purpose of this study was to evaluate the effect of the shear rate on red blood cell (RBC) aggregation with power Doppler ultrasound scanning (PDU), pulsed-wave Doppler scanning, and color Doppler flow imaging. METHODS Equine and porcine blood were circulated with a steady flow in a phantom with a diameter of 9.52 mm. The color Doppler flow(More)
The objective was to design a vascular phantom compatible with digital subtraction angiography, computerized tomography angiography, ultrasound and magnetic resonance angiography (MRA). Fiducial markers were implanted at precise known locations in the phantom to facilitate identification and orientation of plane views from three-dimensional (3-D)(More)
The Doppler signal is generally considered as a Gaussian random process. However, to date very little experimental validation of this model has been available. Recently, the K model was proposed to describe the statistical properties of ultrasonic radio frequency signals and their envelopes. The coefficient of kurtosis, which has been shown to be related to(More)
The main objective of the present work was to investigate, under pulsatile flow, the patterns of variation of the Doppler power backscattered by blood and Sephadex particles upstream and downstream of concentric and eccentric stenoses ranging from 47% to 91% area reduction. Doppler measurements were performed at 5 diameters upstream and 5, 10, 15 and 20(More)
OBJECTIVES In many pathological conditions, including high-risk surgery, the severity of the inflammatory response is related to the patient outcome. However, determining the patient inflammatory state presents difficulties, as markers are obtained intermittently through blood testing with long delay. RBC aggregation is a surrogate marker of inflammation(More)
PURPOSE To compare the creation of carotid atherosclerotic plaque after stenosis creation with absorbable or permanent suture in a diabetic dyslipidemic swine model. MATERIALS AND METHODS A high-cholesterol diet was fed to 15 Sinclair pigs. Diabetes was induced by intraarterial injection of streptozotocin. Stenosis creation in carotid arteries was(More)
PURPOSE The purpose of this study was to provide a quantitative evaluation of the effect of adjacent segment lesions on disease classification in lower limb arteries by ultrasonic duplex scanning. METHODS Lower limb arterial duplex scanning from the distal aorta to the popliteal artery was performed in 55 patients. Arterial lesions evaluated by visual(More)