Bend-insensitive fiber optic ultrasonic tracking probe for cardiovascular interventions

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Surgical Instrumentation

Background:

• Transesophageal echocardiography (TEE) is crucial for guiding medical device placement in cardiovascular procedures.
• Accurate visualization and localization of device tips with TEE can be challenging, particularly with steerable instruments.
• Existing fiber optic ultrasound sensors (FOUS) integrated with TEE probes can lose sensitivity when bent beyond specifications.

Purpose of the Study:

• To develop and demonstrate a bend-insensitive FOUS for improved ultrasonic tracking.
• To evaluate the utility of this new FOUS for guiding steerable device tips during TEE procedures.

Main Methods:

• Fabricated FOUS using standard and bend-insensitive single-mode fibers, subjecting them to static bending.
• Compared interference transfer functions and ultrasound sensitivities of both FOUS types.
• Integrated bend-insensitive FOUS into a steerable guide catheter and measured signal-to-noise ratios (SNR) in a cardiac phantom under various deflection states.

Main Results:

• Standard FOUS lost all ultrasound sensitivity when bent below a 10 mm radius.
• Bend-insensitive FOUS maintained performance, showing a SNR of 36.8 at a 3.0 mm bend radius.
• In a steerable catheter, the bend-insensitive FOUS achieved mean SNRs of 195 (straight) and 163 (fully deflected).

Conclusions:

• The bend-insensitive FOUS effectively overcomes the limitations of standard FOUS in high-curvature applications.
• This technology enables reliable ultrasonic tracking for a broader range of cardiovascular devices.
• Improved device localization enhances safety and efficacy in minimally invasive TEE-guided procedures.