Endoscopic optical coherence tomography angiography using an externally driving catheter

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Optical Coherence Tomography

Background:

• Endoscopic optical coherence tomography (OCT) provides subsurface imaging of tubular organs.
• Existing endoscopic OCT angiography (OCTA) systems using internal-motor-driving catheters face challenges with mechanical instability.
• This instability hinders the differentiation of fine capillaries within tissues.

Purpose of the Study:

• To develop and evaluate an endoscopic OCTA system utilizing an external-motor-driving catheter.
• To overcome limitations of conventional externally driven systems, specifically mechanical instability and motion artifacts.
• To enable high-resolution visualization of microvasculature in challenging anatomical locations.

Main Methods:

• Implementation of OCTA with an external-motor-driving catheter in an endoscopic OCT system.
• Utilization of a high-stability inter-A-scan scheme for enhanced image acquisition.
• Application of the spatiotemporal singular value decomposition algorithm for blood vessel visualization.
• Mitigation of nonuniform rotation distortion and physiological motion artifacts.

Main Results:

• Successful visualization of microvasculature in a custom-made microfluidic phantom.
• Demonstration of submucosal capillary visualization in the mouse rectum.
• Validation of the system's capability to overcome catheter-induced distortions and motion artifacts.
• Successful imaging with a miniaturized catheter (outer diameter < 1 mm).

Conclusions:

• The proposed endoscopic OCTA system with an external-motor-driving catheter effectively visualizes microvasculature.
• This technology offers improved stability and artifact reduction compared to previous methods.
• The small catheter size facilitates potential early diagnosis of cancers in narrow lumens, such as pancreatic and bile ducts.