Laser Atherectomy Photoacoustic Guidance for CTO Vessel Crossing
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Solution Overview
Problem
Current endovascular therapies for peripheral arterial disease (PAD) lack effective visual guidance during laser atherectomy procedures, particularly for crossing chronic total occlusions (CTOs), leading to complications such as vessel wall punctures and improper saline flushing due to the inability of x-ray imaging to show soft tissue contrasts.
Innovation Solution
Integration of an external ultrasound imaging probe in photoacoustic imaging mode with a laser atherectomy system, utilizing multiple pulsed wavelengths and a trigger line, to generate real-time feedback through photoacoustic signals for improved tissue differentiation and procedural guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If x-ray imaging is used for guidance during laser atherectomy, then procedural guidance is provided, but soft tissue contrast is not visible leading to inability to differentiate tissue types
Solution Approach 1:
The patent combines x-ray imaging capabilities with optical imaging capabilities into a single hybrid imaging system. The x-ray source and detector are integrated with optical light sources and detectors, allowing simultaneous acquisition of both bone/contrast agent information and soft tissue information. This merging resolves the contradiction by providing tissue differentiation information that x-ray alone cannot provide, while maintaining a unified system architecture rather than requiring separate imaging systems.
Solution Approach 2:
The imaging system is designed to perform multiple functions: x-ray imaging for bone and contrast visualization, optical imaging for soft tissue differentiation, and photoacoustic imaging for functional information. This multi-functional system provides comprehensive tissue characterization needed for laser atherectomy guidance, addressing the information loss limitation of single-modality imaging while consolidating capabilities into one universal platform.
2Loss of information
If traditional ultrasound imaging is used, then real-time imaging is provided, but ability to differentiate between tissue types with different chemical compositions is limited
Solution Approach 1:
The patent merges traditional ultrasound imaging with optical imaging and photoacoustic imaging modalities. The ultrasound transducers are integrated with optical detectors and light sources, enabling simultaneous acquisition of structural information (ultrasound) and chemical composition information (optical absorption spectra). This combination provides real-time imaging capability while overcoming the limitation of tissue differentiation, as each modality complements the others without requiring separate systems.
Solution Approach 2:
The imaging system incorporates multiple imaging modalities (ultrasound, optical, photoacoustic) that can be activated simultaneously or sequentially to provide comprehensive tissue characterization. This multi-functional approach enables differentiation of tissue types based on multiple parameters (acoustic properties, optical absorption, photoacoustic response) while maintaining real-time imaging capability through integrated data acquisition and processing.
3Reliability
If laser atherectomy is performed without visual guidance, then procedure can be performed, but complications such as vessel wall punctures occur due to lack of real-time feedback
Solution Approach 1:
The patent integrates multiple imaging modalities (x-ray, optical, ultrasound, photoacoustic) into a unified guidance system that provides comprehensive real-time feedback during laser atherectomy. The merged system displays fused images from all modalities, enabling clinicians to visualize both hard tissue boundaries and soft tissue structures simultaneously. This integration significantly improves procedural safety by preventing vessel wall punctures through real-time anatomical visualization, while consolidating multiple imaging functions into one coordinated system rather than requiring separate guidance systems.
Solution Approach 2:
The imaging system provides continuous real-time feedback during laser atherectomy procedures through dynamic image acquisition and display. The system monitors tissue characteristics, laser-tissue interaction, and catheter position in real-time, allowing immediate adjustment of procedural parameters. This feedback mechanism enhances reliability by enabling clinicians to respond to changing anatomical conditions, prevent complications, and optimize treatment delivery throughout the procedure.
4Measurement precision
If multiple pulsed wavelengths are used for photoacoustic imaging, then tissue type differentiation is improved, but energy consumption increases
Solution Approach 1:
The patent employs periodic pulsed laser illumination at multiple wavelengths rather than continuous illumination. The laser delivers short pulses at specific intervals, allowing tissue to return to baseline between pulses. This periodic action enables acquisition of photoacoustic signals from multiple wavelengths sequentially, providing comprehensive tissue spectral information while minimizing total energy delivery. The pulsed regime reduces heat accumulation and overall energy consumption compared to continuous multi-wavelength illumination.
Solution Approach 2:
The system applies partial illumination by selecting only the specific wavelengths most relevant to the tissue differentiation task at hand, rather than using the full spectral range continuously. The laser system can selectively activate subsets of wavelength channels based on the imaging depth, tissue type, and diagnostic requirements. This partial action approach provides sufficient measurement precision for tissue characterization while significantly reducing energy consumption by avoiding unnecessary wavelength activations.
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
Enhances procedural safety and efficacy by providing real-time visual and audible alerts for clinicians, reducing complications and improving tissue ablation control through precise tissue type differentiation and catheter orientation.
Implementation Method 1
collecting real-time streaming data from laser atherectomy therapy characterizing the biological tissues around a therapeutic region with an analysis of photoacoustic signals produced
Implementation Method 2
laser atherectomy is a process that can be used to enable crossing through chronic total occlusions (CTO) via a wire
Implementation Method 3
perform operations of tissue ablation directed to the anatomical condition
Data Source
Figure 1A~1E
Figure 2A~2C
Figure 3A~3B
AI summary
Methods, Apparatuses, and Systems of operating a laser atherectomy system to perform an endoscopic atherectomy procedure within a vessel at a therapeutic region of an anatomical condition by use of an atherectomy laser device coupled to an ultrasound imaging probe. The atherectomy laser device operates to generate photoacoustic signals from a light source of the atherectomy laser device to for guidance within the vessel and to characterize tissue about the therapeutic region by delivery of pulsed wavelengths within the vessel, and to perform operations of tissue ablation directed to the anatomical condition. This enables guidance of the atherectomy laser device by feedback from the viewing of photoacoustic images based on photoacoustic signals generated the atherectomy laser device and created in response to changes in acoustic intensity due to changes of optical wavelength monitored by the ultrasound imaging probe.