Miniature actuator mechanism for intravascular optical imaging

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. A variation uses the actuator mechanism to rotate only the distal end of the optical fiber, eliminating the need to spin the entire fiber via a remote mechanism. Also disclosed are methods of using the same.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority under 35 U.S.C. 119 to U.S. Provisional Application Ser. No. 60 / 678,676, filed May 4, 2005, titled “Multiple transducers for large field of view in intravascular ultrasound imaging,” U.S. Provisional Application Ser. No. 60 / 677,944, filed May 4, 2005, titled “Shape memory alloy (SMA) mechanism for side-looking intravascular imaging,” U.S. Provisional Application Ser. No. 60 / 710,304, filed Aug. 22, 2005, titled “Guide wire enabled with intravascular ultrasound imaging for interventional applications,” and U.S. Provisional Application Ser. No. 60 / 711,653, filed Aug. 25, 2005, titled “Miniature mirror-based intravascular ultrasound imaging device for interventional applications,” and U.S. Provisional Application Ser. No. 60 / 781,786, filed Mar. 13, 2006, titled “Electrically driven miniature intravascular optical coherence tomography imaging device,” the entire contents of each of which are incorporated herein...

AI Technical Summary

Problems solved by technology

Coronary artery disease is very serious and often requires an emergency operation to save lives.

Unfortunately, with X-ray fluoroscopic images, there is a great deal of uncertainty about the exact extent and orientation of the atherosclerotic lesions responsible for the occlusion, making it difficult to find the exact location of the stenosis.

In addition, though it is known that restenosis can occur at the same place, it is difficult to check the condition inside the vessels after surgery.

Existing intravascular imaging devices are too large and insufficiently flexible to be placed simultaneously with other devices.

These devices have limitations in incorporating other interventional devices into a combination device for therapeutic aspects.

They require a large space inside catheter such that there is not enough room to accommodate other interventional devices.

Also due to the nature of the rotating shaft, the distal end of the catheter is very stiff and it is hard to go through tortuous arteries.

The high speed rotating shaft also contributes to distorted non-uniform images when imaging a tortuous path in the vasculature.

This approach also has problems, including for example the manipulation, spinning and scanning motion required with respect to a delicate glass or polycarbonate optical fiber; the actuator mechanism located outside the patient and tip located inside the patient are significantly distant from one another, leading to inefficiencies and control issues arising from the torque created by a long, spinning member; and remote mechanical manipulation and a long spinning element distort the image due to non-uniform rotational distortion.

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