How to Get Prior Auth for Imaging: Complete Guide

Radiology prior authorization is one of the most significant administrative burdens in American healthcare — and one of the most common reasons patients don't get the imaging their doctors ordered. This guide explains how imaging prior authorization works, what the approval process looks like, and what to do when it goes wrong.

What Is Radiology Prior Authorization?

Prior authorization (prior auth or PA) is a requirement by your health insurer that your doctor get approval before ordering certain imaging tests. For most major commercial insurers and Medicare Advantage plans, MRI, CT scan, PET scan, and nuclear medicine studies require prior authorization. Some plans also require auth for certain ultrasounds, echocardiograms, and nuclear stress tests.

Insurers defend prior auth as a cost and quality control measure — ensuring that imaging is clinically appropriate before it is performed. Critics (including physician groups, the AMA, and patient advocacy organizations) argue that prior auth creates delays, causes harm, and is often applied inconsistently.

Who Handles Imaging Prior Authorization?

Most major insurers outsource radiology prior authorization to Radiology Benefit Managers (RBMs), which are third-party companies specializing in imaging utilization management. The major RBMs include:

• AIM Specialty Health (used by BCBS plans, Cigna, and others)
• National Imaging Associates (NIA) (used by some Aetna and Humana plans)
• MedSolutions (used by some regional plans)
• eviCore healthcare (used by UnitedHealthcare and others)

Your physician's office submits the authorization request to the RBM (not directly to the insurer), and the RBM evaluates the request against clinical criteria.

How Prior Auth for Imaging Works

1. Your physician orders imaging. The order must include the relevant diagnosis, symptoms, and clinical findings.
2. Your physician's office submits a prior auth request to the insurer or RBM through an online portal, fax, or phone.
3. The RBM or insurer evaluates the request against clinical criteria (InterQual, MCG, or proprietary guidelines).
4. Decision: Approved, denied, or pended for additional information.
5. If denied: Your physician can request a peer-to-peer review.

Urgent cases: Most insurers offer an expedited authorization track for urgent clinical situations. Federal law requires Medicare Advantage plans to decide urgent prior auth requests within 72 hours. For commercial plans, state law varies, but most require 72-hour decisions for urgent cases.

Gold Card Laws: Exemption from Prior Auth

Several states have passed Gold Card laws that exempt high-performing physicians from prior authorization requirements:

• Texas (HB 3459, 2021): Physicians with a 90%+ approval rate with a specific insurer over 12 months are exempt from prior auth for that insurer for those services.
• Georgia: Similar Gold Card legislation.
• Illinois: Gold Card provisions as part of broader PA reform.
• Ohio, Michigan, and others: Have introduced or are considering Gold Card legislation.

At the federal level, the Improving Seniors' Timely Access to Care Act (2022) requires Medicare Advantage plans to implement electronic prior authorization and sets transparency standards — a step toward broader reform.

Ask your physician's office whether they are gold-carded with your insurer. If so, the prior auth requirement should not apply to your imaging order.

Peer-to-Peer Review: The Most Effective Tool

When an imaging authorization is denied, your physician can request a peer-to-peer review — a direct phone conversation between your physician and the insurer's or RBM's medical reviewer. This is often the fastest and most effective way to reverse a denial.

Tips for effective peer-to-peer review in imaging:

• Request it immediately after denial — most plans allow 14 days
• The calling physician should be the ordering provider, not office staff
• Prepare the specific clinical findings, symptom timeline, and prior workup results
• Know the specific denial reason and address it directly
• Reference ACR Appropriateness Criteria for your imaging indication
• Note urgency if delay could result in harm

Peer-to-peer review reverses a substantial percentage of imaging denials, often in the same phone call.

What Happens If You Got Imaging Without Prior Auth

If imaging was performed without prior authorization and you receive a retroactive denial, you are not necessarily stuck. Options include:

• Emergency exception: Prior auth is not required for emergency imaging. If the imaging was performed in a true emergency, document this and appeal.
• Good cause exception: If the imaging was urgent and there was no time to obtain authorization, or if the insurer's system was unavailable, document the circumstances.
• Provider responsibility: In many cases, prior auth is the provider's responsibility, not the patient's. If the provider failed to obtain auth, the provider may be obligated to write off the balance — you should not be balance billed for the provider's administrative error.

Tips From Radiology Practice

Radiologists and radiology practice managers offer these insights on getting imaging authorized:

1. Document clinical indications clearly. Vague orders like "back pain — MRI" are denied more often than specific orders with documented clinical findings, timeline, and prior treatment.
2. Match your diagnosis code to the imaging ordered. Mismatched codes are a common reason for administrative denial.
3. Be specific about the body part and protocol. "MRI lumbar spine without and with contrast for suspected disc herniation with nerve compression" is more approvable than "MRI spine."
4. Submit supporting documentation upfront. Attach the office visit note with the auth request — it saves time.
5. Use the insurer's preferred submission channel. Most RBMs and insurers have online portals that are faster than fax.

ACR Appropriateness Criteria

The American College of Radiology (ACR) publishes ACR Appropriateness Criteria — evidence-based guidelines for appropriate imaging in specific clinical scenarios. These are free to access at acr.org/acrappropriateness and are widely recognized by insurers, RBMs, and IRO reviewers. When your imaging request aligns with ACR Appropriateness Criteria for your specific clinical indication, reference these criteria in the prior auth request and in any appeal.

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Related Reading:

• How to Write an Insurance Appeal Letter
• What Is Medical Necessity?
• What Is Prior Authorization?