​To effectively treat strokes, a fast, accurate diagnosis is vital. Currently, the techniques used to diagnose different kinds of strokes all require major medical imaging equipment like MRIs and X-ray scanners that are not generally available in emergency rooms and that can be difficult to access rapidly. If ultrasound could be used to diagnose stroke, around 140,000 people who suffer strokes each year in France alone could benefit from faster and more effective treatment.

Traditionally, a distinction is made between two kinds of strokes, each with its own treatment protocol. Currently, MRI and X-ray tomography are the two main techniques used to diagnose strokes. Ultrasound is much easier to access, cheaper, and more compact than these techniques, making it suitable for use on board ambulances, for instance. The problem is that the skull prevents the ultrasound waves from propagating correctly, which has a substantial negative impact on the quality of the image.

Researchers at CEA-List are using models they developed to simulate the propagation of ultrasound waves in complex solid materials for non-destructive testing applications to simulate the disturbances to ultrasound wave propagation caused by the presence of the skull between the ultrasound probe and tissue observed. If the morphology of the skull wall is known, the phase laws to apply to the multielement probe can be calculated, offsetting the disturbances to the ultrasound wave front.

The researchers were able to refocus the ultrasound waves on the soft cranial tissue and significantly improve the quality of the ultrasound image. The next step will be to demonstrate the advantages of this kind of adaptive imaging method (developed for NDT) and use it to develop a stand-alone imaging system.