Off-Axis Optical Fiber OCT Catheter Imaging

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Solution Overview

Problem

Current OCT imaging catheters face challenges in achieving real-time, full circumferential views with minimal impact on crossing profile, particularly due to the use of large and complex rotating junctions that cause back-reflections and alignment issues, making them unsuitable for small diameter body lumens and increasing costs.

Innovation Solution

The implementation of an OCT catheter with an off-axis optical fiber that rotates independently of the catheter body, using a fiber management pathway to prevent excessive bending and tangling, allowing for common-path interferometry and 360° circumferential imaging without breaking the fiber continuity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fiber rotating junction (FORJ) is used to enable circumferential OCT imaging, then full circumferential field of view is achieved, but device complexity and cost increase significantly

Engineering Contradiction:
Improvecircumferential field of viewVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent removes the complex FORJ component from the system entirely. Instead of using a fiber rotating junction with spinning mirrors or prisms, the invention uses a simpler fiber termination with adhesive that forms a single reference reflection, eliminating the need for rotating optical elements and complex alignment mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention is designed for single-use disposable catheters, eliminating the need for expensive, fragile rotating mechanisms. The fiber termination uses simple adhesive bonding rather than complex mechanical rotating junctions, making the device cost-effective for single-use applications.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Adaptability or versatility

If a FORJ with spinning mirrors or prisms is used for OCT imaging, then circumferential views are obtained, but crossing profile is significantly increased

Engineering Contradiction:
Improvecircumferential imaging capabilityVSAvoidcrossing profile
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent removes large rotating mechanisms (spinning mirrors, prisms, and FORJs) from the catheter distal tip. The fiber is terminated directly with adhesive, creating a compact imaging tip that maintains a small crossing profile suitable for navigating tortuous vessels.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If a FORJ is used to rotate the optical fiber for imaging, then circumferential views are achieved, but back-reflections and alignment issues occur

Engineering Contradiction:
Improvecircumferential imagingVSAvoidimage quality
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent removes the FORJ component that causes back-reflections and alignment issues. The fiber is terminated directly with adhesive at a single location, creating a stable reference reflection without the complications of rotating junctions and multiple optical surfaces.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention creates a stable optical reference by terminating the fiber with adhesive that forms a consistent reference reflection. This eliminates the need for complex FORJ alignment while maintaining reliable interferometry for OCT imaging.

Inventive Principle:
Principle #26Copying

4Reliability

If the optical fiber is positioned off-axis in the catheter, then common-path interferometry is preserved, but fiber management becomes more complex

Engineering Contradiction:
Improveinterferometry performanceVSAvoidfiber management
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent pre-plans the fiber pathway through the catheter body, routing the off-axis fiber through a dedicated channel that maintains proper geometry and prevents tangling. The fiber is positioned and secured during manufacturing to ensure consistent off-axis alignment for common-path interferometry.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables high-resolution, real-time imaging with minimal impact on the catheter's crossing profile, reducing costs and improving accessibility to tortuous vessels, while maintaining image quality and reducing the risk of fiber damage.

Implementation Method 1

an optical fiber extending along the length of the catheter body while being radially displaced (off-axis) from the longitudinal axis (midline) of the catheter body

Methodology Applied
Scientific EffectOptical fiber transmission: Optical Fibre

Implementation Method 2

catheter-based off-axis optical coherence tomography imaging system

Methodology Applied
Scientific EffectMechanical rotation:

Data Source

PatentEP2448472B1Catheter-based off-axis optical coherence tomography imaging system
Publication Date: 2019.04.03 AVINGER INC
  • EP2448472B1 patent drawingFigure 1
  • EP2448472B1 patent drawingFigure 2A~2B
  • EP2448472B1 patent drawingFigure 3A~3B

AI summary

Catheter-based Optical Coherence Tomography (OCT) systems utilizing an optical fiber that is positioned off-axis of the central longitudinal axis of the catheter have many advantage over catheter-based OCT systems, particularly those having centrally-positioned optical fibers or fibers that rotate independently of the elongate body of the catheter. An OCT system having an off-axis optical fiber for visualizing the inside of a body lumen may be rotated with the body of the elongate catheter, relative to a handle portion. The handle may include a fiber management pathway for the optical fiber that permits the off-axis optical fiber to rotate with the catheter body relative to the handle. The system may also include optical processing elements adapted to prepare and process the OCT image collected by the off-axis catheter systems described herein.