What to Expect During Common Medical Imaging Tests

Medical imaging allows a care team to look at structures or activity inside the body without surgery. An image may help investigate a symptom, check an injury, guide treatment, or monitor a known condition. Although X-rays, CT scans, MRI scans, and ultrasound exams all create images, they use different equipment and may require different preparation.

Begin with the exact name of the imaging test

Ask which exam was ordered and which part of the body will be imaged. Similar-sounding tests may use different techniques or preparation. The order also tells the imaging team what clinical question the ordering clinician wants the exam to help answer. If the test name, body area, or reason for the exam seems different from what you discussed, ask for clarification before the appointment.

Confirm whether the test uses contrast material, whether eating or drinking instructions apply, and whether you need to arrive early. Current information about radiology services belongs on the hospital services page. Appointment and scheduled-care guidance is available through patient information. Do not rely on a third-party directory for time-sensitive availability or scheduling details.

How common imaging tests differ

X-ray

An X-ray uses a small amount of ionizing radiation to create images, often of bones or the chest. A technologist positions the body part between the equipment and an image detector. You may stand, sit, or lie down and may be asked to hold still or briefly hold your breath. The actual exposure is usually very quick, though positioning and obtaining all requested views take additional time.

CT scan

Computed tomography, or CT, uses X-rays and computer processing to produce detailed cross-sectional images. During the scan, the patient lies on a table that moves through a short, ring-shaped opening. The equipment may make humming or whirring sounds. A technologist can see, hear, and communicate with the patient from a nearby control area.

MRI scan

Magnetic resonance imaging, or MRI, uses a strong magnetic field and radio waves rather than ionizing radiation. The patient usually lies on a table that moves into a tube-shaped scanner. The machine makes loud tapping, knocking, or thumping sounds, so hearing protection is typically provided. Several image sequences may be collected, and remaining still is important.

Ultrasound

Ultrasound uses high-frequency sound waves to create images. A technologist usually places gel on the skin and moves a handheld device called a transducer over the area. Pressure may be needed to obtain clear views and can feel uncomfortable over a tender spot. Ultrasound does not use ionizing radiation.

Preparation varies with the body area. Some exams may require a period without food, while others may require drinking water and arriving with a full bladder. These instructions are not interchangeable. Follow the directions for the exact ultrasound ordered and contact the department if completing them would be difficult.

A practical imaging appointment checklist

Before the appointment

• Write down the test name, body area, date, arrival time, and location.
• Confirm that the imaging order has been sent or bring it if instructed.
• Read the preparation directions early enough to ask questions.
• Ask whether food, drink, medicines, or activity require special handling.
• Confirm whether contrast material is planned and what safety information is needed.
• Gather identification, insurance information, and requested records or device details.
• Discuss mobility, communication, anxiety, pain, or positioning needs in advance.

At the appointment

• Tell staff if you could not follow an instruction exactly.
• Complete safety questions accurately, even if the information seems unrelated.
• Report possible pregnancy, relevant allergies, kidney problems, implants, and prior reactions when asked.
• Remove only the clothing or objects staff identify and store valuables safely.
• Ask how you can communicate with the technologist during the exam.
• Before leaving, confirm who will share the result and what follow-up is expected.

Food, drink, and medicine instructions

Many imaging exams do not require fasting, but some do. The correct directions depend on the test, the body area, use of contrast, and other clinical factors. Ask for a clear start time and what counts as food or drink. If you ate or drank outside the instructions, tell the imaging team rather than canceling on your own or withholding the information.

Do not stop or change a prescription, nonprescription medicine, vitamin, or supplement based on general advice. Ask the ordering clinician or imaging department how to handle your usual medicines. People with diabetes or other conditions that make fasting or medication timing complicated should request an individualized plan.

When imaging is part of a visit that also includes blood or other specimen collection, each test may have separate instructions. The guide to preparing for laboratory tests explains how to confirm those requirements without confusing them with imaging preparation.

Safety screening matters

Imaging staff use screening questions to choose safe procedures and prepare for individual needs. Give complete answers about pregnancy or possible pregnancy, allergies, kidney disease, implanted devices, metal exposure, recent procedures, and previous reactions to contrast material. A reported concern does not automatically mean the test cannot be performed; it gives the care team information needed to decide the appropriate next step.

For MRI, mention devices such as pacemakers, pumps, stimulators, clips, hearing implants, or other implanted or attached items. Bring the device card or manufacturer information if requested. Loose metal objects and many electronic items must remain outside the magnet area. Follow staff directions about phones, keys, watches, jewelry, removable dental items, hearing aids, and clothing with metal.

If contrast is planned, the team may ask additional health questions or require recent laboratory information. A past reaction, allergy, or kidney concern should be described accurately, including what happened and when. Do not premedicate yourself or assume that one type of contrast is the same as another.

Staying comfortable and still

Clear images often depend on positioning and stillness. Tell the technologist before the exam if pain, breathing difficulty, limited movement, or another condition could make a position hard to maintain. Staff may be able to explain supports or pauses appropriate for the exam. Trying silently to endure an impossible position can lead to movement and repeated images.

People who feel anxious in enclosed spaces should discuss that concern with the ordering clinician and imaging department before the appointment. Ask what the equipment is like, how long individual image sequences may last, and how staff maintain communication. Do not take a sedating medicine unless it has been prescribed or approved for that purpose, and confirm transportation requirements if sedation is part of the plan.

What happens after the images are taken

The technologist may review the images for technical completeness before you leave. This check does not usually provide a diagnosis. A qualified clinician interprets the exam and sends a report to the ordering clinician, who considers it alongside symptoms, history, examination findings, and other tests.

Ask how results are normally delivered and when to contact the ordering office if you have not heard. Do not assume that a delay means the result is normal or abnormal. If the exam involved contrast or sedation, follow the specific aftercare instructions you receive. Seek urgent help for severe or rapidly worsening symptoms; for an apparent life-threatening emergency, call 911.

Questions to ask before a radiology test

• What is the exact test, and which body area will be imaged?
• What preparation applies to me, including food, drink, medicines, and arrival time?
• Will contrast material be used, and what health information do you need?
• What should I bring regarding implants or medical devices?
• How long should I plan to be at the facility?
• What will I need to remove or change before the exam?
• How can I communicate discomfort or anxiety during the test?
• Who will interpret the images, and how will I receive the result?

Frequently asked questions

Can I eat before a medical imaging test?

It depends on the exact exam. Some tests have no food restriction, while others require specific preparation. Use the instructions from the ordering clinician or imaging department and call if they are unclear.

Will an imaging test hurt?

The imaging itself is often painless, but positioning, pressure from an ultrasound transducer, an IV placement, or remaining still may cause discomfort. Tell the technologist about pain or limitations so the team can respond appropriately.

Why do I need to remove jewelry or metal?

Objects can obscure an image, and metal presents additional safety concerns in the MRI environment. Remove only what staff instruct you to remove and tell them about any item that cannot be taken off.

Does every CT or MRI use contrast?

No. Whether contrast is used depends on the exam and the clinical question. Ask in advance whether it is planned and what preparation or screening applies.

Can the technologist tell me what the images show?

The technologist's role includes obtaining technically useful images. Interpretation is generally completed by a qualified clinician, with the report sent to the ordering clinician. Ask how and when that clinician will discuss the result with you.

What if I am pregnant or might be pregnant?

Tell the ordering clinician and imaging staff before the exam. They can evaluate the test, timing, and appropriate precautions based on the clinical situation. Do not make the decision to proceed or cancel without speaking to the care team.