Ultrasound is a noninvasive procedure with no radiation risk to patient or examiner.
Little, if any, patient preparation and aftercare is required.
The examination can be repeated as often as necessary without being injurious to the patient. No harmful cumulative effect has been seen.
Ultrasound is useful in the detection and examination of moving parts, such as the heart.
Injection of contrast materials or isotopes or ingestion of opaque materials is not required.
An extremely skilled examiner is required to operate the transducer. The scans should be read immediately and interpreted for adequacy. If the scans are not satisfactory, the examination must be repeated.
Air-filled structures (e.g., the lungs) cannot be studied by ultrasonography.
Certain patients (e.g., restless children, patients who are extremely obese) cannot be studied adequately unless they are specially prepared.
The following general categories of patients may provide some difficulties in ultrasound studies:
Postoperative patients and those with abdominal scars: The area surrounding an incision is to be avoided whenever possible. If a scan must be performed over an incision, the dressing must be removed and a sterile coupling agent and probe must be used.
Children and agitated adults: Because the procedure requires the patient to remain still, some patients may need to be sedated so that their movements do not cause artifacts.
Patients who are obese: It may be difficult to obtain an accurate scan on a patient who is obese, owing to alteration of the sound beam by fatty tissue.
Barium has an adverse effect on the quality of abdominal studies, so sonograms should be scheduled before barium studies are performed.
A large amount of gas in the bowel may require that the examination be rescheduled because air (bowel gas) is a very strong reflector of sound and does not permit accurate visualization.