We describe an ultrasound+CT image fusion and instrument guidance system based on a visual tracking approach. Using multimodality markers, registration is very unobtrusive, and standard instruments do not require any calibration. A novel deformation estimation algorithm shows externally-induced tissue displacements in real time. We characterize the performance of the clinical system on phantoms...

mean VCF by this noninvasive technic in patients studied by both methods. In 15 patients considered to have normal left ventricular function, the average mean VOF determined by ultrasound was 1.29 + 0.23 circumferences/sec, while in the 13 patients with reduced left ventricular performance this value was 0.75 + 0.16 circumferences/ sec (P < 0.001). Values of mean VCF by the two technics were si...

The aim of this retrospective study was to evaluate the accuracy of gynecology and obstetrics residents when performing ultrasonographic estimation of fetal weight. The total of 400 ultrasonographic estimations of fetal weight and corresponding neonatal weight were collected and divided into 3 groups according to physicians' experience (junior and senior residents, staff physicians). The accura...

The speed of sound in soft tissues is usually assumed to be 1540 m/s in medical pulse-echo ultrasound imaging systems. When the true speed is different, the mismatch can lead to distortions in the acquired images, and so reduce their clinical value. Previously we reported a new method of sound-speed estimation in the context of image deconvolution. Unlike most other sound-speed estimation metho...

We propose a beamforming scheme for ultrasound imaging leading to the generation of two sets of images, one with oscillations only in the axial direction and one with oscillations only in the lateral direction. Applied to tissue elasticity imaging, this leads to the development of a specific displacement estimation technique that is capable of accurate estimation of two components of the displa...

Cardiac motion estimation is an important diagnostic tool for detecting heart diseases and it has been explored with modalities such as MRI and conventional ultrasound (US) sequences. US cardiac motion estimation still presents challenges because of complex motion patterns and the presence of noise. In this work, we propose a novel approach to estimate cardiac motion using ultrafast ultrasound ...

Ultrasound elasticity imaging has been developed over the last decade to estimate tissue stiffness. Shear wave elasticity imaging (SWEI) quantifies tissue stiffness by measuring the speed of propagating shear waves following acoustic radiation force excitation. This work presents the sequencing and data processing protocols of SWEI using a Verasonics system. The selection of the sequence parame...

The understanding and exploitation of acoustic echo signals from nonlinear ultrasound scatterers is an active research area that aims to improve the sensitivity and specificity of diagnostic imaging.Discriminating between acoustic echoes from linear scatterers, such as tissue, and nonlinear scatterers, such as contrast microbubbles, based on their frequency content is also an important topic in...

6 June 2016 6 GLOBAL TIME DELAY 2D ESTIMATION IN ULTRASOUND ELASTOGRAPHY. Hoda Sadat Hashemi1,2, Hassan Rivaz1,2. 1Department of Electrical and Computer Engineering, Concordia University, 1455 De Maisonneuve Blvd. W., Montreal, Quebec, H3G1M8, CANADA; 2PERFORM Center, 7200 Sherbrook St. W., Montreal, Quebec, H4B1R6, CANADA. Background: Correlation methods are commonly used for Time-Delay Estima...