2D array imaging system for mechanically-steered, forward-viewing ultrasound guidewire.

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Vascular Surgery

Background:

• Peripheral artery disease (PAD) affects millions, with critical limb ischemia often necessitating revascularization.
• Chronic total occlusions (CTOs) present a significant challenge in PAD revascularization, leading to high failure rates.
• Current minimally-invasive techniques struggle with navigating tortuous vessels and CTOs, highlighting the need for advanced guidewire technology.

Purpose of the Study:

• To develop and evaluate a steerable robotic guidewire with integrated forward-viewing imaging capabilities.
• To enable enhanced navigation through complex vasculature and facilitate crossing of CTOs in PAD interventions.
• To improve the success rates of revascularization procedures by overcoming limitations of current guidewire technology.

Main Methods:

• Design and fabrication of a miniature, 9-element (3x3) 2D array transducer operating at 17 MHz.
• Implementation of a hybrid beamforming approach for synthetic aperture imaging using mechanical and electronic steering.
• Acoustic characterization and ex vivo imaging of vascular targets, including a porcine iliac artery.

Main Results:

• The 2D array transducer demonstrated a mean resonance frequency of 17.6 MHz and a -6 dB bandwidth of 35%.
• Achieved lateral and axial resolutions of 0.271 mm and 0.122 mm, respectively.
• The 2D array system showed significant improvements over a single-element transducer, including a 4.8 dB SNR increase and enhanced resolution (58.5% lateral, 17.3% axial).

Conclusions:

• A novel 2D array imaging system integrated into a mechanically-steered guidewire was successfully developed and demonstrated.
• This system offers improved frame rates and field of view compared to single-element transducers.
• The robotic guidewire with 2D imaging shows promise for improving outcomes in PAD revascularization, particularly in cases involving CTOs.