How to Prepare for an Ultrasound Test

Ultrasound diagnostic exams involve sound waves traveling throught the body and sending back "echoes" which register on the test screen. Since sound travels poorly through gas, it is necessary for patients to be as gas-free as possible for most tests. Gas usually affects areas of the body that have the gastrointestinal tract running through them, such as the abdomen and part of the pelvis. Other times, a full bladder can enhance sound waves and create a clearer ultrasound picture. Ultrasound test preps therefore involve fasting and sometimes drinking liquids to create the best pictures. Read on to learn more.

Instructions

Difficulty: Moderately Easy

Things You’ll Need:

• 3 8 oz. glasses of clear liquids

1. If you are having an abdominal ultrasound (one that examines abdominal organs such as the liver, spleen, kidneys, pancreas and/or gallbladder), it's necessary to fast for at least 4 to 5 hours before the test. For best results, schedule an appointment before noon and fast from midnight the night before until the test.
2. For renal (kidney) and bladder tests, pelvic exams and certain pregnancy exams, fill your bladder with 24 oz. (3 8 oz. glasses) of clear fluid and finish the prep at least one hour prior to the exam. You will need to hold your bladder until the test is done. For best results, eat lightly 8 hours before the exam to avoid gas bubbles which can cloud the picture.
3. For small parts, such as the thyroid, breast(s) and testicles, merely show up for the exam. There are no specific preps for these tests.
4. There are no preps for most vascular exams such as the carotid arteries and the legs (venous doppler exams). The exception is the abdominal aorta exam, in which you must fast as you would for an abdominal exam.
5. For a transvaginal ultrasound, the prep happens at the test location, when you will be asked to empty your bladder completely. Restricting liquid intake before the test is also a good idea.