Widespread availability of ultrasound imaging in the past two decades has dramatically changed the practice of obstetrics and gynaecology. These specialists rely heavily upon this technology to make major decisions about management of their patients.
Trans abdominal sonography (TAS) images the pelvic organs through the anterior abdominal wall in the supra-pubic region. A distended urinary bladder is essential to displace the bowel loops and to provide an acoustic window. There are two major limitations of TAS. First is the need to use lower frequencies for imaging due to the longer distance between the transducer and the pelvic organs. Other disadvantage is the beam degrading effect of the anterior abdominal wall especially in obese patients. Both these limitations lead to degradation in image quality.