There are, however, significant limitations. An ultrasound examination can be thought of as looking at the body through a cardboard tube. You only see anatomy which is directly scanned by the probe. Lesions deep to, or beside the area scanned can be missed. Sound waves are also degraded at the rate of 1 decibel per cc of tissue per MHz. As a result, obese patients do not ultrasound well. In addition, abdominal imaging requires the use of a fluid filled bladder or a solid organ (liver, spleen) as an acoustic “window”.
