The double aorta - Rarity or artifact of ultrasound examination.

The double aorta is very rare. Only two cases are described in the literatu re. More frequent is a duplication artifact which is misinterpreted as bein g the image of a double aorta. This is caused by a refraction artifact whic h results from the difference in the velocity of sound between muscle tissu e and fat tissue. Furthermore, a fat depot between parts of the rectus abdo minis muscle has a prism-like effect. In most cases, this artifact can be a voided by lateral shifting of the transducer.