Your doctor may order an ultrasound if you’re having pain, swelling, or other symptoms that require an internal view of your organs.
Most ultrasounds require no preparation by the patient. However, some do require you to fast for eight to 12 hours, especially if your abdomen is being examined. Your doctor will advise you in advance.
Ultrasound is a safe procedure that uses low-power sound waves.
Although ultrasound is a valuable tool, it has limitations. Sound doesn't travel well through air or bone, so ultrasound isn't effective at imaging parts of your body that have gas in them or are hidden by bone. To view these areas, your doctor may order other imaging tests, such as CT or MRI scans or X-rays.