For Patients

How to Prepare for Your Imaging Exam

Big Sky Imaging · September 4, 2026

Most imaging needs no preparation whatsoever. A few studies need something specific, and getting that wrong is the single most common reason a scan has to be rescheduled. Five minutes of reading here saves a wasted trip.

We tell you exactly what applies to your exam when we schedule it. This page is so you know why.

Chart showing preparation required for each type of imaging study: fasting, full bladder, or none — Preparation by study type. Most of what we do needs none at all.

Studies that need fasting

Abdominal, gallbladder and liver ultrasound. Nothing to eat or drink beforehand. The reason is mechanical: the gallbladder fills between meals and collapses after one, and a collapsed gallbladder is very hard to assess. Eating first is the difference between a diagnostic study and one that has to be repeated.

Take your regular medications with a small sip of water unless your provider has told you otherwise. If you are diabetic, say so when you schedule, because a long fast is not a neutral instruction for you and we will work around it.

Studies that need a full bladder

Pelvic ultrasound, and obstetric studies in early pregnancy. A full bladder pushes bowel out of the way and creates a clear window to see through. Arrive without having emptied it. This is uncomfortable and it is genuinely necessary; there is no way to produce the same view otherwise.

For a transvaginal study, the opposite applies and an empty bladder is preferred. If your order includes both approaches, we will explain the sequence.

Studies that need nothing

Thyroid and neck, soft tissue, breast, carotid and most vascular studies, X-ray and EKG all need no preparation at all. Eat normally, take your medications, arrive as you are.

Aortic studies are the one vascular exception, where fasting produces clearer images.

What to bring and wear

Your provider's order, if you have a paper copy
Photo ID and insurance card if you are billing insurance
A list of your medications
Two-piece clothing that is easy to move. You will often not need to change at all
For an EKG, something that opens at the front

Leave jewellery at home where you can. For X-ray, metal in the field of view has to come off.

If we are coming to you

Mobile visits need one thing from the location: a space the technologist can work in. Room to get equipment beside the bed or chair, somewhere to plug in, and someone available who knows the patient. If the patient has mobility limitations, isolation precautions, or anything else that changes the approach, tell us when the order is placed rather than when we arrive.

Common questions

What happens if I eat by mistake?

Call us before your appointment rather than after. Depending on the study and how long ago you ate, we may still be able to proceed, or we may move you rather than produce images the radiologist cannot read. Either way it is a better conversation before the visit.

Can I take my medications?

In almost all cases yes, with a small sip of water. If your provider has given you a specific instruction about a medication, theirs overrides ours.

How long will I be there?

Most ultrasound studies run 20 to 45 minutes depending on scope. X-ray and EKG are much quicker, often under fifteen minutes including getting settled. An echocardiogram runs 30 to 60 minutes.

Can someone come in with me?

Usually yes, and for patients with dementia or anxiety it often makes the study go better. Tell us when scheduling so we plan for the room.

Should I stop eating before an X-ray or EKG?

No. Neither needs any preparation at all. If someone has told you to fast for one of those, check the instruction, because it may have been meant for a different study.