Correction of distortion in US images caused by subcutaneous tissues: results in tissue phantoms and human subjects

To correct distortion in ultrasonic images caused by refraction at fat-muscle interfaces in the subcutaneous tissues.A forward-propagation technique was developed that used a priori information of the acoustic properties of the layers. The thickness and shape of these tissues were measured, and a correction was applied for the different velocities in the tissues. A synthetic-aperture scanning technique was used to allow correction to be applied with data obtained in a single scan. The technique was tested in three tissue phantoms with overlying aberrating layers (six images) and in eight volunteer subjects (37 images). The superior mesenteric artery and the aorta were used as test sites within the body, because it is relatively easy to obtain double images of these vessels owing to refraction of the scanning beam by the rectus muscles.Distortions such as double-image artifacts and texture disruption were corrected with use of this technique. Six of the six phantom images and 22 of the 37 images in humans were corrected with use of this technique.The forward-propagation technique compensates for refraction at subcutaneous fat-muscle interfaces.