Optical Tracking for Freehand Swept Synthetic Aperture Imaging

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Biomedical Engineering

Background:

• Ultrasound (US) imaging faces diffraction limits, hindering deep tissue resolution.
• Swept synthetic aperture (SSA) techniques enhance imaging aperture using transducer motion.
• Freehand SSA offers adaptability but requires precise positioning.

Purpose of the Study:

• Introduce the optically tracked SSA (OT-SSA) platform for high-resolution ultrasound.
• Address image degradation from spatial calibration, tracking precision, and out-of-plane motion.
• Evaluate OT-SSA's effectiveness in real-time, adaptable imaging.

Main Methods:

• Developed an optically tracked SSA (OT-SSA) system integrating external tracking.
• Analyzed and mitigated spatial calibration errors and tracking inaccuracies.
• Assessed out-of-plane motion effects on image quality.
• Performed in vivo quadriceps imaging using the OT-SSA platform.

Main Results:

• OT-SSA demonstrated substantial resolution gains in in vivo imaging.
• Reduced average lateral speckle autocorrelation size from 2.33 mm to 0.49 mm.
• Compared favorably against stationary aperture imaging techniques.

Conclusions:

• OT-SSA provides a robust and adaptable solution for high-resolution ultrasound imaging.
• The platform effectively overcomes limitations of freehand SSA.
• Enables improved visualization of deeper tissue structures.