Ultrasound imaging, also called ultrasound scanning or sonography, is a method of obtaining images of internal organs by sending high-frequency sound waves into the body. The reflected sound waves' echoes are recorded and displayed as a real-time visual image. No ionizing radiation (x-ray) is involved in ultrasound imaging. An abdominal ultrasound is a useful way of examining internal organs, including the liver, gallbladder, spleen, pancreas, kidneys and bladder. Because ultrasound images are captured in real time they can show movement of internal tissues and organs and enable physicians to see blood flow. This can help to diagnose a variety of conditions and to assess damage caused by illness.

Ultrasound:Gallbladder
Ultrasound: Kidney
Ultrasound: Liver

Ultrasound imaging is used extensively for evaluating the kidneys, liver, gallbladder, pancreas, spleen and blood vessels of the abdomen. Because it provides real-time images, it can also be used to:

• Guide procedures such as needle biopsies in which needles are used to sample cells from organs for laboratory testing.
• Help a physician determine the source of many abdominal pains, such as an inflamed appendix or stones in the gall bladder or kidney.
• Help identify the cause for enlargement of an abdominal organ.

Doppler ultrasound is a special type of ultrasound study that examines major blood vessels. These images can help the physician to see and evaluate:

• Blockages to blood flow, such as clots.
• Build-up of plaque inside the vessel.
• Congenital malformation.
• With knowledge about the speed and volume of blood flow gained from an ultrasound image, the physician can often determine whether a patient is a good candidate for a procedure like angioplasty.

Ultrasound waves are reflected by air or gas; therefore ultrasound is not an ideal imaging technique for the bowel. Barium exams and CT scanning are the methods of choice for bowel-related problems in most cases.

Ultrasound waves do not pass through air; therefore an evaluation of the stomach, small intestine and large intestine may be limited. Intestinal gas may also prevent visualization of deeper structures such as the pancreas and aorta. Patients suffering from obesity are more difficult to image this is because tissue attenuates (weakens) the sound waves as they pass deeper into the body.

Ultrasound has difficulty penetrating bone and therefore can only see the outer surface of bony structures and not what lies within and beyond. For visualization of bone, other imaging modalities, such as MRI (magnetic resonance imaging), may be selected.