Abstract: This invention provides small position sensors for applications where localized sensing in a small volume of space is needed but where measurement of large relative displacement is also necessary. The invention enables a surgeon to accurately position the tip of a catheter during minimally invasive therapy. The current invention further improves the quality of tactile feedback to a physician during catheter-based surgeries with an axial force sensor at the tip of the catheter that allows for the transmission of force information to the physician. One embodiment of this invention is a position sensor for active interventional catheters, where the sensor may be laser-machined shape memory alloy (SMA), and the catheter actuators may be heated SMA or wire-pulleys. Providing position feedback from a catheter during minimally invasive therapy allows for closed-loop control of the catheter tip position under computer-aided guidance and enable force feedback to the physician.

Abstract: The present invention relates to a new intravascular imaging device based on a Shape Memory Alloy (SMA) actuator mechanism embedded inside an elongate member such as a guide wire or catheter. The present invention utilizes a novel SMA mechanism to provide side-looking imaging by providing movement for an optical coherence tomography (OCT) element. This novel SMA actuator mechanism can be easily fabricated in micro-scale, providing an advantage over existing imaging devices by offering the ability to miniaturize the overall size of the device. Because the device does not require a rotating shaft or fiber optic along the length of the catheter, it also allows for a more flexible catheter or guide wire, and provides room for other interventional devices. The device simplifies the manufacture and operation of OCT by allowing a straight fiber optic directed by an independent, oscillating reflector or prism controlled by the actuator mechanism located only in the distal tip of the device.

Abstract: A micromanipulator comprising a tubular structure and a structural compliance mechanism that are formed from a tube made of an elastic and/or superelastic material. The micromanipulator is useful for intravascular interventional applications and particularly ultrasonic imaging when coupled with an ultrasound transducer. Also disclosed are medical devices for crossing vascular occlusions using radio-frequency energy or rotary cutting, preferably under the guidance of real-time imaging of the occlusion, as well as accompanying methods.

Abstract: A shape memory alloy (SMA) actuator made from tubular structures is disclosed. The current invention is a tubular monolithic SMA actuator made from a tubular monolithic SMA substrate of NiTi, CuAlNi, CuAl, CuZnAl, TiV, or TiNb. The tubular monolithic SMA actuator has a first end, a second end and a middle portion, and can be made out or a substrate with a cross-section shape such as a circle, an ellipse, a rectangle or any irregular shape. The middle portion is formed into an actuator pattern that maintains unity and electrical continuity, along the path of the actuator pattern, with the first end and second end. The actuator pattern can be any number of patterns, for example, a Greek key pattern or a zigzag pattern. A first electrode is optionally formed in the first end and a second electrode is formed in the second end of the tubular monolithic SMA actuator.

Abstract: The present invention relates to a new intravascular ultrasound imaging device with an increased field of view. By using more than one ultrasound transducer crystal that is capable of producing an ultrasonic signal for imaging, and preferably aligning the individual crystals on a shared backing with at least one edge of the crystals in contact, the field of view generated by a given actuator mechanism is increased without substantially increasing the overall dimensions of the device. Also disclosed are methods of using the same.

Abstract: The present invention relates to a new intravascular imaging device based on a Shape Memory Alloy (SMA) actuator mechanism embedded inside an elongate member such as a guide wire or catheter. The present invention utilizes a novel SMA mechanism to provide side-looking imaging by providing movement for an ultrasound transducer element. This novel SMA actuator mechanism can be easily fabricated in micro-scale, providing an advantage over existing imaging devices because it offers the ability to miniaturize the overall size of the device, while the use of multiple transducer crystals maximizes field of view. Also disclosed are methods of using the same.

Abstract: A micromanipulator comprising a tubular structure and a structural compliance mechanism that are formed from a tube made of an elastic and/or superelastic material. Fabricated with laser machining and has no mechanical joints, the micromanipulator can be manipulated in various motions and degree-of-freedoms without permanent deformation. Shape Memory Alloys (SMAs) in one embodiment are implemented as main actuators of the micromanipulator. The micromanipulator can be implemented with multiple SMAs to manipulate the mechanism with multiple degree-of-freedom. In another implementation, multiple segments of the mechanisms are formed and arranged in various configurations, including a “double-helix”-like configuration, for enabling intricate motions of the micromanipulator. The micromanipulator is useful for intravascular interventional applications and particularly ultrasonic imaging when coupled with an ultrasound transducer.

Abstract: A technique for enhancing the image quality in intravascular ultrasound imaging increases contrast between blood and vessel wall processes image data using a point-wise t-statistic technique. Data from an ultrasound transducer is digitized and stored in a memory buffer [500]. For each point in the image, a t-statistic value is derived from signal amplitude values for the same point at a sequence of previous frames [502]. An image is then generated and displayed using the t-statistic values for the intensity of each point [504]. The improvement in contrast ratio as compared to averaging techniques is most significant at highly oblique angles when contrast ratio is particularly poor in the unprocessed signal.

Abstract: The present invention provides actuators and actuator devices that take advantage of a strain gradient variation of an actuator element between a first phase and a second phase. The actuator elements can be positioned in any type of shape. For instance, the actuator element in the first phase can be any type of curved, non-linear or irregular shape as long as a strain gradient along a cross-section of the actuator element can be established. The actuator element in the second phase is positioned in a different shape when compared to the first phase as long as it is in a direction to minimize the strain gradient. Different actions can be generated such as a rotary movement, a linear movement, an expanding movement, or a combined linear and rotary movement. The actuator element could also be configured to generate a linear movement by combining contraction and strain gradient variation.

Abstract: A micromanipulator comprising a tubular structure and a structural compliance mechanism that are formed from a tube made of an elastic and/or superelastic material. Fabricated with laser machining and has no mechanical joints, the micromanipulator can be manipulated in various motions and degree-of-freedoms without permanent deformation. Shape Memory Alloys (SMAs) in one embodiment are implemented as main actuators of the micromanipulator. The micromanipulator can be implemented with multiple SMAs to manipulate the mechanism with multiple degree-of-freedom. In another implementation, multiple segments of the mechanisms are formed and arranged in various configurations, including a “double-helix”-like configuration, for enabling intricate motions of the micromanipulator. The micromanipulator is useful for intravascular interventional applications and particularly ultrasonic imaging when coupled with an ultrasound transducer.

Abstract: The present invention provides actuators and actuator devices that take advantage of a strain gradient variation of an actuator element between a first phase and a second phase. The actuator elements can be positioned in any type of shape. For instance, the actuator element in the first phase can be any type of curved, non-linear or irregular shape as long as a strain gradient along a cross-section of the actuator element can be established. The actuator element in the second phase is positioned in a different shape when compared to the first phase as long as it is in a direction to minimize the strain gradient. Different actions can be generated such as a rotary movement, a linear movement, an expanding movement, or a combined linear and rotary movement. The actuator element could also be configured to generate a linear movement by combining contraction and strain gradient variation.