An imaging guidewire can include one or more optical fibers communicating light along the guidewire. At or near its distal end, one or more blazed or other fiber Bragg gratings (FBGs) directs light to a photoacoustic transducer material that provides ultrasonic imaging energy. Returned ultrasound is sensed by an FBG sensor. A responsive signal is optically communicated to the proximal end of the guidewire, and processed to develop a 2D or 3D image. In one example, the guidewire outer diameter is small enough such that an intravascular catheter can be passed over the guidewire. Techniques for improving ultrasound reception include using a high compliance material, resonating the ultrasound sensing transducer, using an attenuation-reducing coating and/or thickness, and/or using optical wavelength discrimination. Techniques for improving the ultrasound generating transducer include using a blazed FBG, designing the photoacoustic material thickness to enhance optical absorption. Techniques for distinguishing plaque or vulnerable plaque may be used to enhance the displayed image.

Systems and methods for minimally-invasive optical-acoustic imaging

The present invention is a guide wire imaging device for vascular or non-vascular imaging utilizing optic acoustical methods, which device has a profile of less than 1 mm in diameter. The ultrasound imaging device of the invention comprises a single mode optical fiber with at least one Bragg grating (8), and a piezoelectric or piezo-ceramic jacket (31), which device may achieve omnidirectional (360°) imaging. The imaging guide wire of the invention can function as the guide wire for vascular interventions, can enable real time imaging during balloon inflation, and stent deployment, thus will provide clinical information that is not available when catheter based imaging systems are used. The device of the invention may enable shortened total procedure times, including the fluoroscopy time, will also reduce radiation exposure to the patient, and the operator.

Optical-acoustic imaging device

An imaging guidewire can include one or more optical fibers communicating light along the guidewire. At or near its distal end, one or more blazed or other Fiber Bragg Gratings (FBGs) can direct light to a photoacoustic transducer material that provides ultrasonic imaging energy. Returned ultrasound can be sensed by an FBG sensor. A responsive signal can be optically communicated to the proximal end of the guidewire, and processed such as to develop a 2D or 3D image. In an example, the guidewire outer diameter can be small enough such that an intravascular catheter can be passed over the guidewire. To minimize the size of the guidewire, an ultrasound-to-acoustic transducer that is relatively insensitive to the polarization of the optical sensing signal can be used. The ultrasound-to-optical transducer can be manufactured so that it is relatively insensitive to the polarization of the optical sensing signal.

Optical ultrasound receiver

A reversible thermochromic composition develops fluorescent color of yellow, yellowish orange, orange, reddish orange, or red with a high color density and high color brightness, yet gives no residual color under non-color-developing conditions, and has remarkably improved light resistance. The reversible thermochromic composition, comprising a solubilized mixture of three components of (a) an electron-donating color-developing organic compound selected from pyridine types, quinazoline types, and bisquinazoline types of compound, (b) an electron-accepting compound for the electron-donating color-developing organic compound, and (c) a compound serving as a reaction medium for causing reversibly an electron exchange reaction between the components (a) and (b) within a specified temperature range.

Reversible thermochromic composition

A color-change material has a reversibly thermochromic layer and a porous layer containing a low-refractive-index pigment. The color-change material changes its color in response to heat or water. The reversibly thermochromic layer and the porous layer are superposed on each other, or the reversibly thermochromic layer and the porous layer are formed side by side. Alternatively, a color-change material has a substrate and formed thereon a color-changing porous layer including a reversibly thermochromic material, a low-refractive-index pigment, and a binder. The reversibly thermochromic material and the pigment are dispersed in the binder and tenaciously adherent thereto.

Color-change materials

A thermochromic color-memory compositions exhibiting high color contrast between high color density in a colored state and sufficiently low color density in a decolored state with high freedom of selection of the reaction medium, and highly useful as a thermochromic material. The thermochromic color-memory composition comprises a homogeneous solubilized mixture of essential three components of (a) an electron-donating color-developing organic compound, (b) an electron-accepting compound, and (c) a reaction medium for controlling a color reaction of the component (a) with the component (b); the component (c) being selected from aliphatic ketones of 10 to 22 total carbons and aryl alkyl ketones of 12 to 24 total carbons; and the composition changing the color thereof with a large hysteresis width (ΔH) of from 8° C. to 80° C.

Yutaka Shibahashi

Papers

Thermochromic color-memory composition