Design and Simulation of a Ring-Shaped Linear Array for Microultrasound Capsule Endoscopy.

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Gastroenterology

Background:

• Video capsule endoscopy (VCE) has revolutionized gastrointestinal visualization over the past two decades.
• Integrating microultrasound imaging into VCE presents significant design challenges due to size constraints and electronic requirements.

Purpose of the Study:

• To describe a simulation process for evaluating transducer geometries and imaging methods for ultrasound capsule endoscopy (USCE).
• To address the design tradeoffs necessary for developing a novel USCE device.
• To assess imaging performance within the physical limitations of a capsule.

Main Methods:

• A hybrid MATLAB model was developed, integrating Krimholtz-Leedom-Matthaei circuit elements, digitizing, and beamforming for B-mode image rendering.
• Acoustic propagation models were used to generate images of point scatterers.
• Simulations tested a USCE transducer configuration with a segmented transmit ring and a 512-element receive linear array, operating at a 25 MHz center frequency.

Main Results:

• Simulated B-scan images were generated for wire phantoms, multilayered phantoms, and a gut wall model.
• A digital phantom, derived from ex vivo porcine small bowel scans at 45 MHz, demonstrated the system's tissue imaging capabilities.

Conclusions:

• The simulation process effectively evaluates USCE transducer designs and imaging methodologies.
• The study outlines critical design tradeoffs for developing miniaturized ultrasound capsule endoscopy systems.
• The proposed USCE configuration shows potential for enhanced gastrointestinal visualization.