An MRI gets denied. Your staff drafts an appeal, sends it to the payer, and waits.

Weeks later, still nothing. Eventually someone calls to check status, and the answer is worse than a rejection: the appeal was never actually reviewed. It went to the wrong place entirely, and the real appeal window has been quietly closing the whole time it sat, unprocessed, at the payer.

This isn't a rare clerical accident. It's one of the most common ways imaging appeals fail — and it has nothing to do with the strength of the clinical case.

The payer usually isn't who reviewed your request

For advanced imaging — MRI, CT, PET — most payers don't review the prior authorization themselves. They delegate it to a radiology benefit manager, and which one depends entirely on the payer and the specific plan:

• EviCore handles Cigna, Aetna commercial, Humana, and UnitedHealthcare's Oxford plans
• Carelon Medical Benefits Management handles Anthem/Elevance and many Blue Cross Blue Shield plans
• Evolent/RadMD handles regional BCBS plans and Medicaid managed care organizations

A few payers still review imaging internally rather than delegating it — UnitedHealthcare's main commercial and Medicare Advantage business among them.

That means the payer's name on your original claim tells you almost nothing about who to appeal to. The denial notice does.

Why sending it to the wrong place is worse than a slow response

Here's the part that actually costs practices time: an appeal sent to the payer for a denial that a delegated entity issued gets returned unfiled. Not slowly rerouted — returned, unprocessed. And the appeal clock keeps running the entire time it sits in the wrong queue.

So the real failure mode for a lot of practices isn't "we didn't appeal in time." It's "we appealed to the wrong entity, found out weeks later, and by then the window had shrunk or closed entirely."

The routing is also actively changing, not fixed

This is getting more complicated, not less. Aetna's delegation arrangement changed for 2026: per Aetna's 2026 Participating Provider Precertification List, EviCore stopped authorizing imaging for Aetna Individual & Family Plan (IFP) members effective January 1, 2026 — those cases now route through Aetna's own review instead of EviCore.

A practice that's been sending Aetna IFP appeals to EviCore out of habit is now sending them to the wrong place, even if that habit was correct as recently as last year.

Plan type matters here as much as payer name. The same payer can route differently depending on whether the plan is commercial, individual/family, or Medicare Advantage — confirming plan type, not just the payer's name, is part of getting this right.

What actually fixes this

Read the letterhead and the phone number on the denial notice before drafting anything. That single step confirms who actually reviewed the request far more reliably than assuming based on the payer's name.

A few specifics worth knowing for commonly-used payers:

• If a Cigna case was denied by EviCore and a full appeal fails at that level, the next step escalates through Cigna's own National Appeals Unit — not back through EviCore.
• If a payer has recently reduced prior authorization requirements for a specific imaging study, confirm the requirement still applies before submitting anything to a delegated reviewer — submitting to EviCore for a study that no longer needs authorization only adds delay instead of removing it.
• Standard imaging prior authorization decisions must come back within 7 calendar days under CMS-0057-F, effective January 1, 2026 — track that deadline against whichever entity actually holds the request, not just the payer.

A short checklist for the next imaging denial

1. Read the denial letterhead before doing anything else. Confirm whether it names the payer directly or a delegated entity — EviCore, Carelon, or Evolent/RadMD.
2. Confirm the plan type, not just the payer. Commercial, IFP, and Medicare Advantage plans under the same payer can route to different reviewers.
3. Check whether the authorization requirement itself has changed for that specific study before resubmitting — delegation arrangements and PA requirements are both shifting payer by payer this year.
4. Send the appeal to the entity named on the letterhead, not the payer by default. When in doubt, call the number listed on the denial notice to confirm before submitting.

The part worth fixing first

Most imaging appeals don't fail because the clinical case was weak. A meaningful share fail procedurally — sent to the wrong reviewer, under an outdated plan-type assumption, while the actual appeal window quietly runs out. That's a fixable problem, and it doesn't require more staff, just knowing where to look before hitting send.

Keeping track of which entity reviews which payer, and drafting the appeal itself once that's confirmed, is exactly the kind of operational overhead asaanbil.com's claims and appeals module is built to absorb — appeal letters drafted directly from the denial notice, with a physician still reviewing and approving before anything goes out. asaanbil.com (https://asaanbil.com)