Medicare covers CT scans, but only when your doctor orders one for a medical reason — not for screening or peace of mind

Medicare Part B covers CT scans if your doctor believes the scan will help diagnose or treat a condition you have. You pay 20% of the approved amount after you meet your Part B deductible. The scan itself must take place at a facility Medicare recognizes, such as a hospital, imaging center, or doctor's office with the right equipment and credentials.

The key word is medically necessary. Medicare will not pay for a CT scan ordered just to check your overall health or because you want one. Your doctor has to document in your medical record why the scan is needed — for example, to look for a tumor, check for internal bleeding, or evaluate chest pain. If Medicare later reviews the claim and decides the scan was not medically necessary, you could be responsible for the full bill.

Key Takeaways

  • Medicare Part B covers CT scans when a doctor orders them to diagnose or treat a specific medical condition.
  • You pay 20% of the Medicare-approved amount after meeting your Part B deductible, which is $240 in 2024.
  • The imaging facility must be Medicare-approved; ask your doctor's office to confirm before scheduling.
  • Screening CT scans — such as lung cancer screening for heavy smokers — have different rules and may be covered under separate Medicare guidelines.
  • If your doctor orders a CT scan at an out-of-network facility without prior approval, you may owe more than 20%.

How much you pay out of pocket

After you meet your Part B deductible for the year, Medicare pays 80% of the approved amount for a CT scan, and you pay 20%. The Part B deductible was $240 in 2024, but it changes each year. If you have not met your deductible yet, you pay the full deductible first, then 20% of the remaining cost.

The actual bill depends on where you have the scan done. A hospital outpatient department typically charges more than an independent imaging center for the same scan. Medicare sets an approved amount for each type of scan at each type of facility, and that approved amount is what the 80/20 split is based on. If the facility charges more than the approved amount, you may owe the difference — this is called balance billing.

If you have a Medigap or Medicare Advantage plan, your out-of-pocket cost may be lower. Medigap plans often cover the 20% coinsurance. Medicare Advantage plans have their own rules and may require you to use in-network facilities or get prior approval.

When Medicare covers screening CT scans

Most CT scans are covered because they diagnose or treat an existing problem. Screening scans — done to look for disease in people with no symptoms — are usually not covered. The main exception is lung cancer screening for people at high risk.

Medicare covers a low-dose CT scan of the chest once per year if you meet all of these conditions: you are between 50 and 77 years old, you have a 30 pack-year smoking history (meaning you smoked one pack a day for 30 years, or two packs a day for 15 years, for example), you currently smoke or quit within the last 15 years, and your doctor orders the scan and documents that you meet the criteria. The scan must happen at a facility that meets Medicare's imaging standards.

Other screening CT scans — such as for colorectal cancer or ovarian cancer — are not covered by Medicare at this time. If your doctor recommends one and you want to proceed, you would pay the full cost yourself.

Getting approval before your scan

You do not always need to get Medicare's permission before having a CT scan, but it is a good idea to check first. If your doctor orders the scan at a hospital outpatient department or a facility you have not used before, ask your doctor's office to verify that the facility is Medicare-approved and that the scan is medically necessary according to Medicare's rules.

Some Medicare Advantage plans require prior authorization — meaning the plan must approve the scan before you have it. If you have a Medicare Advantage plan, call the plan's customer service number on the back of your card and ask whether the scan your doctor ordered needs approval. If it does and you skip this step, you could end up owing the full bill.

If you are unsure whether a scan is covered, you can call Medicare at 1-800-MEDICARE (1-800-633-4227) and give them the scan type and the reason your doctor ordered it. They can tell you whether it is typically covered, though they cannot make a final decision until the claim is submitted.

What happens if Medicare denies the claim

If Medicare reviews your claim after the scan and decides it was not medically necessary, the facility may bill you for the full cost. This is why it matters that your doctor documents the medical reason for the scan in your chart.

If you receive a bill you think is wrong, you have the right to appeal. You can ask your doctor's office or the imaging facility to appeal on your behalf, or you can file an appeal yourself. The facility should have sent you a notice explaining why the claim was denied; that notice will tell you how to appeal and how long you have to do so.

CT scans at hospitals versus imaging centers

The same CT scan costs more when done at a hospital outpatient department than at an independent imaging center, even though the equipment and radiologist may be similar. Medicare's approved amount reflects this difference — it is higher for hospital scans. You pay 20% of whichever approved amount applies, so your out-of-pocket cost will be higher at a hospital.

If your doctor orders a CT scan and you have a choice of where to have it done, ask whether an independent imaging center is an option. You can also ask your doctor's office what the estimated cost will be at each location. Some imaging centers post their prices online or will quote you over the phone.

Both hospitals and imaging centers must be Medicare-approved. If your doctor sends you to a facility that is not Medicare-approved, Medicare will not pay, and you will owe the full bill. Before you schedule, confirm with the facility that it accepts Medicare.

Special situations and exceptions

If you are in the hospital as an inpatient, a CT scan is covered as part of your hospital stay under Part A, not Part B. You do not pay separately for the scan; it is included in your hospital bill.

If you have End-Stage Renal Disease (ESRD) and are on dialysis, Medicare covers CT scans under different rules. Ask your nephrologist or dialysis center how your coverage works.

If you are enrolled in a clinical trial, a CT scan ordered as part of the trial may be covered even if it would not normally be. Ask the trial coordinator whether Medicare will cover the scan.

Frequently Asked Questions

Will Medicare cover a CT scan my doctor recommended but I have not had yet?

Yes, as long as your doctor still believes it is medically necessary and orders it. Medicare does not expire coverage for a recommended scan. However, if your condition changes or your doctor's notes do not clearly explain why the scan is needed, Medicare might deny the claim later. Ask your doctor to document the medical reason in writing before you schedule.

What if I had a CT scan and did not know I would owe 20%?

You are still responsible for the 20% coinsurance after your deductible. If the bill surprises you, contact the imaging facility's billing department and ask for an itemized bill. You can also ask whether they offer a payment plan. If you believe the scan should not have been billed to you at all, you can file an appeal.

Does Medicare cover CT scans with contrast dye?

Yes. A CT scan with contrast dye (injected or swallowed to make certain structures show up better) is covered the same way as a regular CT scan — 80% after your deductible. Tell your doctor if you have kidney problems or a history of allergic reactions to contrast, because this may affect whether the scan is safe for you.

Can I get a CT scan at an out-of-network facility?

If you have Original Medicare (Part A and B), you can have a scan at any Medicare-approved facility, whether it is in-network or out-of-network. You pay 20% of the approved amount either way. If you have a Medicare Advantage plan, out-of-network facilities may cost you more or may not be covered at all — check your plan documents or call customer service before scheduling.

How long does it take Medicare to pay for a CT scan?

The imaging facility usually submits the claim to Medicare within a few days of your scan. Medicare typically processes the claim within two to four weeks. You may receive a bill from the facility before Medicare pays; this is normal. If you do not hear anything after a month, contact the facility's billing department to check the status.