Ultrasonic Imaging of Foreign Inclusions and Blood Vessels Through Thick Skull Bones

Abstract

We report a new progress in the development of a portable ultrasonic transcranial imaging system, which is expected to significantly improve the clinical utility of transcranial diagnostic ultrasound. When conventional ultrasonic phased array and Doppler techniques are applied through thick skull bones, the ultrasound field is attenuated, deflected, and defocused, leading to image distortion. To address these deficiencies, the ultrasonic transcranial imaging system implements two alternative ultrasonic methods. The first method improves detection of small foreign objects, such as bone fragments, pieces of shrapnel, or bullets, lodged in the brain tissue. Using adaptive beamforming, the method compensates for phase aberration induced by the skull and refocuses the distorted ultrasonic field at the desired location. The second method visualizes the blood flow through intact human skull using ultrasonic speckle reflections from the blood cells, platelets, or contrast agents. By analyzing these random temporal changes, it is possible to obtain 2D or 3D blood flow images, despite the adverse influence of the skull. Both methods were implemented on an advanced open platform phased array controller driving linear and matrix array probes. They were tested on realistic skull bone and head phantoms with foreign inclusions and blood vessel models.

Transcranial Ultrasound Imaging with Estimating the Geometry, Position and Wave-Speed of Temporal Bone

“…The former limits the improvements to certain regions called isoplanatic patches [20]. The latter is more practical, especially in emergency medicine services, if the same ultrasound probe is used to obtain the geometry and compressional wave-speed of the skull [21][22][23], but not CT or MRI scans [24][25][26][27].…”

ULA-OP 256: A 256-Channel Open Scanner for Development and Real-Time Implementation of New Ultrasound Methods

“…The fields of application of the system span from vector Doppler investigations [8]- [12] to motion estimation [13]- [16], from nonlinear contrast imaging [17]- [19] to tissue characterization [20]- [22]. The system was also employed to develop innovative beamforming schemes to improve the image quality [23], [24] to compensate for the refraction induced by skull bone [25]- [27] as well as to validate novel ultrasound image formation models [14], [28].…”