Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic tool that uses strong magnetic fields and radio waves to create detailed images of organs and soft tissues. Physicians use this technology to diagnose and monitor conditions ranging from joint injuries to neurological disorders. Medicare covers these diagnostic scans, but coverage is not automatic. Whether a specific MRI is paid for, and how much the patient pays, depends on the setting where the service is performed and whether specific coverage criteria, such as medical necessity, are met.
Outpatient Diagnostic Coverage Through Part B
Medicare Part B, which is Medical Insurance, is the most common way Medicare covers an MRI. Part B classifies the MRI as a diagnostic non-laboratory test. Coverage applies when the scan is ordered by a treating physician and performed in an outpatient setting, such as an independent diagnostic testing facility or a hospital’s outpatient department.
The fundamental requirement for Part B coverage is that the MRI must be “medically necessary.” This means the physician must document that the scan is required to diagnose or treat a disease, injury, or medical condition, adhering to accepted standards of medical practice. If the test is performed solely for screening or without a documented medical need, Medicare may deny the claim, making the beneficiary responsible for the full cost.
After the annual Part B deductible is met, Medicare covers 80% of the procedure’s Medicare-approved amount. The patient is responsible for the remaining 20% coinsurance. To ensure maximum coverage, both the ordering physician and the facility performing the scan must accept Medicare.
Inpatient Coverage Under Part A
An MRI may be covered under Medicare Part A (Hospital Insurance) if the beneficiary has been formally admitted to the hospital as an inpatient. If the MRI is performed during this inpatient stay, the cost of the scan is bundled into the overall payment for the hospital admission.
The Part A structure requires the beneficiary to pay the Part A deductible for the benefit period, which is a single, larger amount than the Part B deductible. Once met, Part A covers all hospital-related costs, including the MRI, for the first 60 days of the stay. This contrasts with Part B outpatient coverage, which requires a 20% coinsurance.
Understanding Patient Financial Responsibility
Out-of-pocket expenses for an outpatient MRI under Original Medicare begin with the annual Part B deductible. For 2025, this deductible is set at $257, which must be paid before coverage starts. After the deductible is met, the beneficiary is responsible for a 20% coinsurance of the Medicare-approved amount.
The total bill for an MRI involves two separate charges: the facility fee and the professional fee. The facility fee covers the technical component, including the use of the MRI machine and staff. The professional fee covers the radiologist’s time to interpret the images and write the final report. Both charges are subject to the 20% coinsurance.
A key factor in determining the patient’s financial responsibility is whether the provider accepts “Medicare Assignment.” By accepting assignment, the provider agrees to accept the Medicare-approved amount as the total payment for the service. This prevents the provider from billing the patient for more than the deductible and 20% coinsurance.
Coverage Rules for Medicare Advantage Plans
Medicare Advantage Plans (Part C) are offered by private insurance companies approved by Medicare. These plans are legally required to cover all benefits provided by Original Medicare, meaning they must cover medically necessary MRIs. However, Part C plans have the flexibility to establish their own rules for accessing these services.
Unlike the standardized 20% coinsurance under Part B, cost-sharing for an MRI in a Part C plan varies significantly. Patients may face fixed copayments that range widely depending on the plan’s design. Many Part C plans also require beneficiaries to obtain prior authorization before receiving an MRI.
Failure to secure required prior authorization can result in the plan denying the claim, leaving the patient responsible for the entire cost of the procedure. Most Part C plans, such as Health Maintenance Organizations (HMOs) or Preferred Provider Organizations (PPOs), utilize provider networks. If a beneficiary receives an MRI outside of the plan’s network, the out-of-pocket costs will be substantially higher or may not be covered at all.