Imaging probe with combined ultrasounds and optical means of imaging

• US 20080177183A1
• Filed: 01/22/2008
• Published: 07/24/2008
• Est. Priority Date: 01/19/2007
• Status: Active Grant

• Current Assignee: Sunnybrook Health Sciences Centre
• Original Assignee: Sunnybrook Health Sciences Centre
• Inventors: Munce, Nigel Robert, Yang, Victor Xiao Dong, Thind, Amandeep Singh, Courtney, Brian, Foster, Francis Stuart
• Granted Patent: US 8,784,321 B2
• Time in Patent Office: Days
• US Class Current: 600/463
• CPC Class Codes: A61B 1/00112 Connection or coupling means
• CPC Class Codes: A61B 1/00172 with means for scanning
• CPC Class Codes: A61B 1/00183 for variable viewing angles
• CPC Class Codes: A61B 5/0035 adapted for acquisition of images from more than one imaging mode, e.g. combining MRI and optical tomography
• CPC Class Codes: A61B 5/0062 Arrangements for scanning
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61B 8/4281 characterised by sound-transmitting media or devices for coupling the transducer to the tissue
• CPC Class Codes: A61B 8/445 Details of catheter construction
• CPC Class Codes: A61B 8/4461 Features of the scanning mechanism, e.g. for moving the transducer within the housing of the probe
• CPC Class Codes: A61B 8/483 involving the acquisition of a 3D volume of data
• CPC Class Codes: A61B 8/5238 for combining image data of patient, e.g. merging several images from different acquisition modes into one image for image registration algorithms G06T7/30
• CPC Class Codes: A61B 8/5292 using additional data, e.g. patient information, image labeling, acquisition parameters
• CPC Class Codes: A61B 8/543 involving acquisition triggered by a physiological signal
• CPC Class Codes: G02B 23/2423 of the distal end
• CPC Class Codes: G02B 6/3604 : Rotary joints allowing relative rotational movement between opposing fibre or fibre bundle ends
• CPC Class Codes: G10K 11/002 : Devices for damping, suppressing, obstructing or conducting sound in acoustic devices G10K1/06 - G10K1/10 take precedence; for electro-mechanical transducers for communication H04R3/002

Abstract

The present invention provides an imaging probe for imaging mammalian tissues and structures using high resolution imaging, including high frequency ultrasound and optical coherence tomography. The imaging probes structures using high resolution imaging use combined high frequency ultrasound (IVUS) and optical imaging methods such as optical coherence tomography (OCT) and to accurate co-registering of images obtained from ultrasound image signals and optical image, signals during scanning a region of interest.

Claims

1. An imaging probe for insertion into bodily lumens and cavities for imaging an interior of said bodily lumens and cavities or imaging exterior surfaces of a body, comprising:

a) an hollow shaft having a longitudinal axis having distal and proximal end sections and an midsection, an imaging assembly being located in said hollow shaft, said imaging assembly being connected to a first end of an imaging conduit, said imaging conduit extending through the hollow shaft and being connectable at a second end thereof to an image processing and display system through the proximal end section, said imaging conduit including a fiber optic having a distal end and said imaging assembly including an optical emitter/collector including light directing and receiving means associated with said distal end of a fiber optic for directing light imaging energy out of a distal end of said fiber optic and receiving reflected light imaging energy signals and directing said received reflected light energy signals back to said image processing and display system, said imaging assembly including an ultrasound transducer and said ultrasound transducer emitting and receiving reflected ultrasound imaging energy signals and said imaging conduit including an electrical conductor for electrically coupling the ultrasound transducer to an ultrasound signal generator connectable to said second end of said imaging conduit, said imaging conduit being connectable at said second end to a source of light;

b) said imaging assembly including a scanning mechanism configured to deliver said light from the optical emitter/collector and ultrasound from said ultrasound transducer along pre-selected paths out of said hollow shaft, the ultrasound transducer and the optical emitter/collector being positioned and oriented relative to each other to enable accurate co-registering of received reflected light imaging energy signals and reflected ultrasound imaging energy signals during scanning a region of interest; and

c) drive mechanism for imparting motion to said imaging conduit and said imaging assembly, said drive mechanism being connectable to a controller which is connectable to said image processing and display system.

2. The imaging probe according to claim 1 wherein said drive mechanism for imparting said motion is a rotary drive mechanism for imparting rotational motion around said longitudinal axis.

3. The imaging probe according to claim 2 wherein said rotary motion occurs at an angular velocity and said angular velocity is adjusted by an adjustment means for the said rotational drive mechanism.

4. The imaging probe according to claim 1 wherein said motion is a reciprocating translational movement of the imaging assembly in the hollow shaft.

5. The imaging probe according to claim 1 wherein said optical emitter/collector and said ultrasound transducer are positioned and oriented relative to each other so that the received reflected light imaging energy signals and reflected ultrasound imaging energy signals are received simultaneously from substantially the same direction along substantially the same path of propagation.

6. The imaging probe according to claim 1 wherein said optical emitter/collector and said ultrasound transducer are positioned and oriented relative to each other to enable imaging of the region of interest with a time delay between obtaining the ultrasound image signals and the optical image signals where the path scanned by a first beam of imaging energy is followed in a predominant manner by a second beam of imaging energy selected, where the first imaging beam is selected from the set of i) a beam of light imaging energy and ii) a beam of ultrasound imaging energy and where the second beam of imaging energy is the imaging beam that was not selected from said set to be the first imaging beam, where said predominant manner is such that during a delay interval starting at an initial time point the axis of said second imaging beam does not align itself further from an initial axis of said first imaging beam, wherein said delay interval ends when the axis of said second imaging beam is substantially aligned with said initial axis.

7. The imaging probe according to claim 1 wherein said optical emitter/collector includes focusing and collection optics for focusing light emitted from said distal end of end of said fiber optic to said region of interest being imaged and for collecting light reflected therefrom.

8. The imaging probe according to claim 1 wherein said optical emitter/collector is embedded in said ultrasound transducer.

9. The imaging probe according to claim 8 wherein said ultrasound transducer has a surface area through which said ultrasound signals are emitted, and wherein said ultrasound transducer has an optically transmissive channel located therein and wherein said optical emitter/collector is located in said optically transmissive channel to emit light through said optically transmissive channel so that the emitted ultrasound signals and the emitted light scan said region of interest at the same time.

10. The imaging probe according to claim 8 wherein said ultrasound transducer has a surface area through which ultrasound signals are emitted, and wherein said optical emitter/collector is mounted with respect to said ultrasound transducer to emit light at a pre-selected angle with respect to the direction in which the ultrasound signals are emitted such that the emitted ultrasound signals and the emitted light scan said region of interest at different times.

11. The imaging probe according to claim 10 wherein said pre-selected angle is selected from the set of 90 degrees, 135 degrees or 180 degrees.

12. The imaging probe according to claim 1 wherein said optical emitter/collector is a first optical emitter/collector, including at least a second optical emitter/collector configured to emit light at a pre-selected angle with respect to the first optical emitter/collector, so that light emitted by the first optical emitter/collector and light emitted by the second optical emitter/collector scan said region of interest at different times.

13. The imaging probe according to claim 12 wherein said first and said at least a second optical emitter/collector are embedded in said ultrasound transducer.

14. The imaging probe according to claim 1 wherein the optical emitter/collector and the ultrasound transducer are coaxially aligned to emit in the same general direction for scanning the same region of interest simultaneously, wherein said scanning mechanism includes a reflective member mounted to reflect said light from the optical emitter/collector and ultrasound signals from said ultrasound transducer.

15. The imaging probe according to claim 14 wherein said reflective member is a movable reflective member, wherein said movable reflective member is mounted in such a way that the variable angle is a function of said pre-selected angular velocity.

16. The imaging probe according to claim 15 wherein said reflective member comprises an acoustically reflective layer and an optically reflective layer, wherein said acoustically reflective layer and said optically reflective layer are separate layers.

17. The imaging probe according to claim 16 wherein said acoustically reflective layer is contoured to focus said ultrasound imaging energy.

18. The imaging probe according to claim 15 wherein the reflective movable member is pivotally mounted in said imaging assembly along a pivot axis perpendicular to said longitudinal axis.

19. The imaging probe according to claim 1 wherein said scanning mechanism includes a movable member to which said optical emitter/collector and said ultrasound transducer are attached, and wherein said movable member is mounted in such a way that the variable angle is a function of said angular velocity.

20. The imaging probe according to claim 19 wherein the movable member is pivotally mounted about a pivot axis perpendicular to the longitudinal axis, and wherein in operation as said imaging assembly rotates, the movable member tilts about said pivot axis as a result of centripetal acceleration, with an amount of tilting being determined by the angular velocity of the imaging assembly which in turn determines the angle that the light and ultrasound energy is emitted from the imaging assembly relative to the longitudinal axis.

21. The imaging probe according to claim 19 wherein the optical emitter/collector and the ultrasound transducer are coaxially aligned to emit in the same general direction for scanning the same region of interest simultaneously.

22. The imaging probe according to claim 19 wherein the movable member is a bendable component including a structural assembly that is constrained at one or more points along its length with respect to its radial distance from the longitudinal axis of the imaging assembly, but is unconstrained over a substantial portion of its length, said optical emitter/collector and said ultrasound transducer being mounted on said unconstrained portion of the bendable component, wherein in operation as said imaging assembly rotates, the bendable component bends as a result of centripetal acceleration, with an amount of bending of the bendable component being determined by the angular velocity of the imaging assembly which in turn determines the angle that the light and ultrasound energy is emitted from the imaging assembly relative to the longitudinal axis.

23. The imaging probe according to claim 1 wherein the optical imaging energy is used to enable imaging by optical coherence tomography.

24. The imaging probe according to claim 1 wherein the optical imaging energy is visible light.

25. The imaging probe according to claim 1 wherein the optical imaging energy is infrared light.

26. The imaging probe according to claim 1 including a rotary encoder mechanism coupled to said imaging assembly and said controller, and wherein said rotational motion of the imaging assembly is detected by said rotary encoder, and wherein said image processing and display system is configured to use said detected rotational motion to infer an imaging angle.

27. The imaging probe according to claim 1 wherein the bodily lumens or cavities include those made by artificial means.

28. The imaging probe according to claim 1 wherein said optical emitter/collector and said ultrasound transducer are positioned and oriented relative to each other so that the ultrasound imaging energy and the optical imaging energy are transmitted simultaneously from substantially the same direction along substantially the same path of propagation from said optical emitter/collector and said ultrasound transducer.

29. The imaging probe according to claim 1 wherein said optical emitter/collector and said ultrasound transducer are positioned and oriented relative to each other so that the ultrasound imaging energy is transmitted and the optical imaging energy is received simultaneously from substantially the same direction along substantially the same path of propagation from said optical emitter/collector and said ultrasound transducer.

30. The imaging probe according to claim 1 wherein said optical emitter/collector and said ultrasound transducer are positioned and oriented relative to each other so that the ultrasound imaging energy is received and the optical imaging energy is transmitted simultaneously from substantially the same direction along substantially the same path of propagation from said optical emitter/collector and said ultrasound transducer.

31. The imaging probe according to claim 1 wherein said image processing and display system is configured to process the images obtained from ultrasound imaging and optical imaging during scanning of a region of interest and to co-register the ultrasound images and optical images and to display the co-registered images.