Ultrasonic echo tomography through skull bone

A special ultrasonic echo-tomography method was applied to trans-skull imaging of the human brain. The method requires only a single scan to acquire data from the object. An ordinary CT-reconstruction scheme with compensation capability for the speed differences due to the skull bone is used. In experiments the subject was immersed in a water bath and scanned by the CT technique. A two-point resolution of about 3 mm was achieved for trans-skull imaging using 1-MHz ultrasound. For comparison, a human brain tumor (oligodendroglioma) was imaged using a commercial 3.5-MHz transducer (B-scan) and the custom 1-MHz transducer, both without intervening skull bone and through skull bone (echo tomography). The results are in good agreement with each other, showing that trans-skull imaging of the brain is feasible. The findings are clinically significant, especially in terms of pediatric brain diagnosis and postoperative follow-up