Shape estimation of flexible ultrasound arrays using spatial coherence: A preliminary study

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Inverse Problems

Background:

• Flexible ultrasound arrays offer advantages like wider field-of-view and better resolution over rigid arrays.
• Accurate element positioning is crucial for beamforming and geometric sonogram reconstruction with flexible arrays.
• Estimating the shape of flexible transducer arrays remains a challenge.

Purpose of the Study:

• To assess the use of spatial coherence in backscattered radiofrequency data for estimating flexible ultrasound transducer array shape.
• To validate the methodology through simulations and in vivo experiments.

Main Methods:

• Developed an inverse problem approach utilizing spatial coherence of ultrasound backscattered data.
• Evaluated the method using simulated flexible arrays.
• Conducted blinded in vivo experiments with commercial rigid transducer arrays on various anatomical targets and phantoms.

Main Results:

• Shape estimation error was below 0.1 wavelengths for simulated arrays.
• In vivo experiments showed an average Euclidean error below 1.4 wavelengths (median 0.58).
• Complex wavelet structural similarity index exceeded 99% for simulations and 96% for experiments.

Conclusions:

• Optimizing spatial coherence is an effective strategy for estimating unknown conformal ultrasound array shapes.
• The proposed method demonstrates high accuracy in both simulated and real-world ultrasound scenarios.
• This technique holds potential for enhancing the performance and reliability of flexible ultrasound imaging systems.