The University of British Columbia

Other

International Business Machines Corporation

Immersion Corporation

Septimiu Edmund Salcudean

Robert Rohling

Peter D Lawrence

Caitlin Marie Schneider

Ali Baghani

Niall R Parker

Michael Jameson

Alexei J Marko

Hani Eskandari

Leo James Stocco

Mohammad Honarvar

Reza Zahiri-Azar

Xu Wen

James Allen McEwen

Samuel Victor Lichtenstein

Ralph L Hollis, Jr

Joseph Yan

Julio Raul Lobo

Robert N Rohling

Stephen H Okazawa

Daniel Ben-Dov

Brian Day

Christopher Yee Chaung Nguan

Allan J Kelley

Amir Hossein Hadi Hosseinabadi

Graham S Bell

Terence J Gilhuly

Danny French

Ana Luisa Trejos

Farrokh Sassani

Icarus C N Chau

Sara Badiei

Afrooz R Ebrahimi

Seyedeh Sara Mahdavi

Samuel V Lichenstein

Kassem A Ashe

Emre Turgay

Simon F Bachmann

Apparatus for measuring forces on a load-carrying element comprises optical sensors mounted to the load-carrying element. Each optical sensor includes a light source, a photosensor and an opaque mask positioned in a light path between the light source and the photosensor. The mask has a window that is movable relative to the photosensor and is located such that light from the light source that passes through the window forms an illuminated region on the photosensor. Each of the optical sensors has a first part which includes the light source and the photosensor that is coupled to the load-carrying element at a first location and a second part that includes the mask that is attached to the load-carrying element at a second location spaced apart from the first location.

Optical force sensors

A system useful for performing ultrasound elastography of organs such as the liver allows efficient and robust data acquisition. The system may be applied to perform real-time, noninvasive ultrasound imaging of the liver in humans. Steady-state, shear wave absolute elastography is used to measure the Young's modulus of the liver tissue. This method involves the use of an external exciter or vibrator to shake the tissue and generate a shear wave. Accurate placement of an ultrasound transducer facilitates measurement of the tissue motion due to the shear wave. The stiffness of tissues in the region being imaged may be computed from the measured tissue motions. The following innovations address both vibrator and transducer placement, as well as some specific methods to ensure adequate wave propagation, in order to obtain accurate and consistent measurements.

Ultrasound shear wave vibro-elastography of the abdomen

A method is described for acquiring 3D quantitative ultrasound elastography volumes. A 2D ultrasound transducer scans a volume of tissue through which shear waves are created using an external vibration source, the synchronized measurement of tissue motion within the plane of the ultrasound transducer with the measurement of the transducer location in space, the reconstruction of tissue displacements and/or tissue velocities in time and space over a volume from this synchronized measurement, and the computation of one or several mechanical properties of tissue from this volumetric measurement of displacements. The tissue motion in the plane of the transducer may be measured at a high effective frame rate in the axial direction of the transducer, or in the axial and lateral directions of the transducer. The tissue displacements and/or tissue velocities over the measured volume may be interpolated over a regular grid in order to facilitate computation of mechanical properties.

Quantitative elastography with tracked 2D ultrasound transducers

A system and method includes applying, by a vibration source, periodic excitation waves to the volume of tissue, the periodic excitation wave having a plurality of phases, acquiring by the CT scanner a first plurality of CT projections at a first phase, the first plurality of CT projections comprising a first CT projection set, acquiring by the CT scanner a second plurality of CT projections at a second phase, wherein the second phase is different than the first phase a second set of CT projections, the second plurality of CT projections comprising a second CT projection set, and determining, based on the first set of CT projections and the second set of CT projections, at least one of a tissue deformation field and a tissue mechanical property of the volume of tissue.

Dynamic computed tomography imaging of elasticity

A method is described for acquiring 3D quantitative ultrasound elastography volumes. In one embodiment, the method comprises using a 2D ultrasound transducer to scan a volume of tissue through which shear waves are created using an external vibration source, the synchronized measurement of tissue motion within the plane of the ultrasound transducer with the measurement of the transducer location in space, the reconstruction of tissue displacements in time and space over a volume from this synchronized measurement, and the computation of one or several mechanical properties of tissue from this volumetric measurement of displacements. The tissue motion in the plane of the transducer may be measured at a high effective frame rate in the axial direction of the transducer, or in the axial and lateral directions of the transducer. The tissue displacements over the measured volume may be interpolated over a regular grid in order to make the computation of mechanical properties easier.

An intra-operative ultrasound probe for use with a robotic and laparoscopic surgical systems that allows for direct surgeon control over the position and orientation of the ultrasound image is presented. The transducer is designed to interface with the laparoscopic grasper so that it is easy to pick up in a locking, self-aligning and repeatable manner. The transducer is tracked in space using either forward kinematics or electromagnetic sensing, allowing multiple 2D images to be combined in order to create 3D ultrasound volumes. The 3D volumes can be further processed and displayed on the surgeon's console, or used to register and display acquired pre-operative images at the correct spatial location within the patient.

Ultrasound probe for laparoscopy

The characterization of tissue viscoelastic properties requires the measurement of tissue displacements over a region of interest at frequencies that exceed significantly the frame rates of conventional medical imaging devices. The present invention involves using bandpass sampling to track high-frequency tissue displacements. With this approach, high frequency signals limited to a frequency bandwidth can be sampled and reconstructed without aliasing at a sampling frequency that is lower than the Nyquist rate. With bandpass sampling, it is feasible to use conventional beam-forming on diagnostic ultrasound machines to perform high frequency dynamic elastography. The method is simple to implement as it does not require beam interleaving, additional hardware or synchronization and can be applied to magnetic resonance elastography.

Bandpass sampling for elastography

Described herein are a method and apparatus for determining viscoelastic parameters of a tissue. A vibration signal is applied to the tissue and displacements at a plurality of locations within the tissue are measured at a plurality of times. The viscoelastic parameters of the tissue, including elasticity and viscosity, can then be determined by fitting a finite element model of the tissue to the vibration signal and the measured displacements and by solving for the viscoelastic parameters of the model. A value for density of each element of the model is selected and the absolute values for the viscoelastic parameters of each of the elements in the model is determined. Alternatively, the difference in relaxation-times between two locations within the tissue can be determined from the difference in phases of the strains at the two locations.

Method and apparatus for determining viscoelastic parameters in tissue

The present invention relates to a method and apparatus for imaging the mechanical properties of a tissue region from within an endocavity of a patient. The apparatus generally comprises an ultrasound probe, a vibration assembly translationally coupled to probe and operable to vibrate the probe along a vibration plane, and a rotation assembly rotationally coupled to the vibration assembly and operable to rotate the probe and vibration assembly about a selected rotational range. The method generally comprises inserting an ultrasound probe into an endocavity of a patient, vibrating the probe along a vibration plane thereby causing deformational excitement of a tissue region contacted by the probe, capturing a first series of ultrasound images of the tissue region, rotating the vibration plane relative to the tissue region by a selected angular rotation, and capturing a second series of ultrasound images of the tissue region.

Method and apparatus for imaging the mechanical properties of tissue from an endocavity

The present invention relates to a method for delineating the contour of an object in captured medical images by first transforming the shape of the object into a simple geometric shape that is more computationally tractable than the shape of the object. After the contour of the transformed shape is detected, the inverse of the transformation is applied to the contour such that it represents the contour of the object in the captured medical image.

Method for automated delineation of contours of tissue in medical images

A method and apparatus for processing ultrasonic image signals is disclosed. The method involves receiving a plurality of input sample values representing reflected sound waves in a ultrasonic system, exponentiating each input sample to produce a plurality of respective exponentiated sample values, conditioning the exponentiated sample values to produce conditioned exponentiated sample values for receipt by an imageformer, and causing the imageformer to produce an image representing the ultrasonic sound waves in response to the conditioned exponentiated sample values.

Method and apparatus for processing ultrasound image signals

An imaging system comprises a device to excite mechanical waves in elastic tissue, a device for measuring the resulting tissue motion at a plurality of locations interior to the tissue at a number of time instances, a computing device to calculate the mechanical properties of tissue from the measurements, and a display to show the properties according to their location. A parameter identification method for calculating the mechanical properties is based on fitting a lumped dynamic parametric model of the tissue dynamics to their measurements. Alternatively, the mechanical properties are calculated from transfer functions computed from measurements at adjacent locations in the tissue. The excitation can be produced by mechanical vibrators, medical needles or structures supporting the patient. The measurements may be performed by a conventional ultrasound imaging system and the resulting properties displayed as semi-transparent overlays on the ultrasound images.

Method for imaging the mechanical properties of tissue

The invention relates to a needle guidance system provided by a needle with a steerable tip. The needle has a cannula and a stylet. The stylet adjacent to its tip has a naturally curved portion. The stylet is movable in two degrees of freedom with respect to the cannula&#x2014;axial translation and axial rotation with respect to the cannula axis. When extended, the stylet curves off-axis and provides cannula tip steering. Driving and/or steering systems may be provided to the orientation and relatively move the stylet.

Steerable needle

A mouse controller includes a platform mounted on a base for a range of movement in a plane relative to the base of at least &#xbd; inch (12.5 mm) in each of two different directions (preferably mutually perpendicular directions). A pair of flat, elongated coils (Lorentz voice coils) are mounted on the platform with their longitudinal axes extending one in each of the two directions. Each of the coils cooperates with at least one magnet fixed to the base. The sizes of the magnets and of the coils and the relative positions of the cooperating coils and magnets are made or their operation controlled so that, in the range of relative movement between the platform and base, preselected forces between the coils and the magnets may be generated by a control computer. Preferably the projected area of the field from each of the permanent magnets onto the coil with which it cooperates will be substantially constant regardless of the position of the platform within the range so that the same current is required to generate the same force anywhere within the range. The control computer is programmed to activate the coils to controllably apply forces to the platform and thereby to facilitate movement of the platform and feed back tactile sensations to the operator.

Controller

A system for medical ultrasound in which the ultrasound probe is positioned by a robot arm under the shared control of the ultrasound operator and the computer is proposed. The system comprises a robot arm design suitable for diagnostic ultrasound, a passive or active hand-controller, and a computer system to co-ordinate the motion and forces of the robot and hand-controller as a function of operator input, sensed parameters and ultrasound images.

Growing community of inventors

Vancouver, Canada

Septimiu Edmund Salcudean