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Updated: Aug 7, 2026
04:54
A Stable Phantom Material for Optical and Acoustic Imaging
Published on: June 16, 2023
Ultrasonic edge shadowing around cylindrical cavities with and without walls
Robin Steel1, Rosemary S Thompson, Charles Macaskill
1School of Mathematics and Statistics, University of Sydney, Sydney, NSW, Australia. rsteel19@yahoo.co.uk
Summary
Edge shadowing in ultrasound images is caused by speed of sound (SOS) differences, not density. These shadows intensify with greater SOS contrast, with inner wall boundaries creating additional shadowing effects.
Area of Science:
- Medical Imaging
- Acoustics
- Ultrasound Physics
Background:
- Speckle patterns in B-mode ultrasound images can be influenced by the acoustic properties of objects.
- Edge shadowing, a specific speckle pattern, is observed distal to cavities with differing speed of sound (SOS).
- Understanding edge shadowing is crucial for accurate interpretation of ultrasound imaging.
Purpose of the Study:
- To investigate the underlying physics of edge shadowing in B-mode ultrasound.
- To determine whether speed of sound (SOS) or density contrasts are the primary cause of edge shadowing.
- To compare the accuracy of wave-based and ray-based acoustic models in simulating edge shadowing.
Main Methods:
- Simulated ensemble-averaged speckle amplitude in B-mode images of cylindrical cavities using the exact wave equation solution.
- Analyzed speckle amplitude and correlation length changes.
- Compared wave-based simulation results with a simpler ray-based acoustic model.
Main Results:
- Edge shadowing is predominantly caused by speed of sound (SOS) contrasts, not density.
- Shadow intensity increases with the magnitude of SOS contrast (up to +/- 10%).
- Walled cylinders exhibit additional shadowing from the inner boundary, absent in wall-less models.
- Wave-based models are necessary for accurately simulating complex shadow regions where ray-based models falter.
Conclusions:
- Speed of sound (SOS) contrast is the dominant factor in ultrasound edge shadowing.
- The wave model provides a more accurate representation of edge shadowing phenomena than ray-based models.
- Accurate simulation of edge shadowing requires considering wave propagation effects, especially near boundaries.
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