Being sent for a scan often arrives with little explanation: a date, a letter and a list of instructions. It is easy to leave the appointment and think of the questions afterwards. This page offers a set of questions, grouped by theme, with the reasons public sources give for asking them. They are prompts for a conversation, not a script, and the answers belong to your own doctor and imaging team. None of them is advice to have or to skip a scan. For the longer account of what happens on the day, see preparing for a scan and your results.
Is this scan the right one for me?
Choosing Wisely, an initiative of the ABIM Foundation, publishes five questions to ask your doctor before any test, treatment or procedure. Applied to imaging they read well: Do I really need this test or procedure? What are the risks and side effects? Are there simpler, safer options? What happens if I don't do anything? How much does it cost, and will my insurance pay for it? The leaflet adds that some medical tests provide little benefit and in some cases may cause harm, and that the aim is the right amount of care, not too much and not too little.
Two further questions are worth asking about imaging in particular. First, what is the scan expected to show that might change the plan? RadiologyInfo.org says it is important to know why you need an imaging exam, and to discuss which exam will best answer the medical question at the lowest radiation dose, adding that many imaging procedures have no or very low radiation dose. Second, could a different method answer the same question? For example, the pages on X-ray, CT and MRI and on ultrasound describe what each is good at, and sources note that MRI or ultrasound can sometimes give the same information without radiation.
What do I need to do beforehand?
Preparation differs from scan to scan, so ask rather than assume. RadiologyInfo.org's preparation pages note that eating and drinking rules vary between exams and facilities, that some exams ask you to fast for hours while some ultrasound exams ask you to drink water and keep a full bladder, and that you should take food and medications as usual before an MRI unless your doctor says otherwise. Questions to put to the team include:
- Should I stop eating or drinking beforehand, and for how long?
- Should I take my usual medicines? Is there any I should leave out?
- Will there be an injection, a drink or a tablet, and why?
- How long should I expect to be there?
- Can someone come with me, and can they stay in the room?
If the scanner worries you, say so early. The NHS advises talking to a healthcare professional before the appointment if you are anxious about a scan or have a fear of small spaces, and says you may be able to have a medicine to help you relax and can ask whether you can bring someone to support you. RadiologyInfo.org says that if you want a mild sedative for an MRI, you should ask your doctor to prescribe it before the date of your exam, and that you should not drive yourself home if you take it.
Safety questions you will be asked, and ones you can ask
Staff will ask about things that affect safety, and it speeds the visit if you have the answers ready. For any scan that uses radiation, the question is whether you could be pregnant or are breastfeeding. For contrast, RadiologyInfo.org lists previous allergic reactions to contrast materials, allergies to food, drugs, dyes or animals, and a history of heart disease, diabetes, kidney disease or thyroid problems. For MRI, the technologist will use a screening form asking about implants and devices. For devices such as pacemakers, the same source says to bring the pamphlet that describes the device if you have it, and to give the device name and manufacturer. The reasons are set out in radiation, contrast and imaging safety.
Questions you can ask in return include whether the dose is adjusted for your size or, for a child, whether the settings have been adjusted for children, which the National Institute of Biomedical Imaging and Bioengineering suggests parents may want to ask. RadiologyInfo.org also suggests keeping a personal record of your X-ray history if you change providers, and bringing copies of earlier scans from other facilities, since comparison with older images can be very helpful. For pregnancy and for children, see imaging, children and pregnancy.
How will I get the results, and what then?
Ask when and how the results will reach you before you leave. The NHS pages on CT and MRI scans say results usually take between 1 and 2 weeks, may take longer, and that if you have heard nothing after a few weeks you should contact the doctor who referred you. RadiologyInfo.org's mammography page adds a line worth remembering for any scan: ask when your results will be available, and do not assume they are normal if you do not hear.
When the report arrives, RadiologyInfo.org's advice on talking to your doctor is to avoid making assumptions about what the report says and to prepare for the discussion instead. It suggests writing down questions in three groups: the exam findings, the impression section and the next steps. It explains that a result may be nothing at all, inconclusive or incidental, that incidental findings are often asymptomatic and have no impact on your care, but that sometimes they can be significant, so it is important to ask your ordering doctor whether a finding is concerning. If more tests are recommended, ask what they hope to find. How a report is organised is described in reading a radiology report.
What will it cost?
Costs vary by country, facility and insurer, and the public radiology sites do not publish them. RadiologyInfo.org says plainly that its website does not provide cost information and that costs may vary by geographic region, and it advises discussing fees with your doctor, the medical facility staff or your insurance provider. Choosing Wisely likewise lists asking what your insurance may cover and whether there are less expensive options. Where costs are not a factor in your health system, you may still want to ask about waiting times.
Frequently asked questions
What should I ask my doctor before a CT or MRI?
Start with why the scan is needed, what it could change, whether a simpler or safer option exists, and what happens if you do not have it. Then ask about preparation, contrast, how long it takes and when results arrive.
Is it okay to question whether I need a scan?
Yes. Choosing Wisely recommends asking whether you really need a test or procedure, what the risks are, and whether there are simpler, safer options, as a way of getting the right amount of care.
What should I tell the imaging staff?
Sources list possible pregnancy, breastfeeding, allergies, kidney, heart, diabetes or thyroid conditions, implants and devices, medicines, and any earlier reaction to contrast. If in doubt, mention it and let the staff decide whether it matters.
What if I do not hear my results?
Do not assume they are normal. The NHS suggests contacting the referring doctor if you have heard nothing after a few weeks, and RadiologyInfo.org advises asking in advance when results will be available.
The short version
Good questions cover four things: why this scan and whether there are simpler options, what to do beforehand, what the safety checks are about, and how and when you will hear. Writing them down before the appointment makes it easier to leave with answers, and the decision about any scan stays with you and your doctor.