Seeing Beyond Obstacles with Ultrasound
New method images tissue that's behind material that is impenetrable to ultrasound.
Ultrasound imaging is a valuable medical technique, but some obstacles, such as bones and air bubbles, are impenetrable to ultrasound. These obstacles block the ultrasound beam and prevent imaging of deeper targets. This means that some structures within the body, such as areas behind the spine, cannot be imaged using regular ultrasound.
A new paper published this month in Scientific Reports describes a method for imaging tissue behind obstacles that are otherwise impenetrable to ultrasound. In the method, called “bypassing ultrasound,” the researchers manipulated the emitted ultrasound field with beam-shaping technology to bypass the obstacle and focus on the object behind it. The resulting images can be processed to reconstruct an image in which the object is visible.
The researchers demonstrated the effectiveness of the technique in simulations with wire targets and simulated tissue made of agarose, as well as in a rat. The method was successful in all the experiments, although performance depended on the transducer size, obstacle width and position, and position of the target.
Overall, the researchers found the new method can image behind ultrasound-impenetrable obstacles such as air bubbles and bones. What’s more, the method can be implemented in commercial ultrasound systems without the need for additional components and the entire process can be performed in real time.
This method could allow clinicians to use ultrasound in currently challenging applications, such as cancer detection, abdominal imaging and spinal imaging.