Open Air, Low Field Strength, and Positional Magnetic Resonance Imaging (MRI) Units — CPB 0093 | AETNA Coverage Update

TL;DR: Aetna, a CVS Health company, modified CPB 0093 covering open, low field strength, and positional MRI units, effective September 26, 2025. Here's what billing teams need to know.

This update confirms Aetna's MRI coverage policy applies across all field strengths and configurations — closed bore, open, low-field, Stand-Up, and seated units alike. The change affects 26 CPT codes spanning brain, spine, pelvis, abdomen, and extremity MRI (70551–74183), plus HCPCS S8042 for low-field MRI specifically. If your practice or imaging center uses open or low-field units to serve claustrophobic, bariatric, or mobility-limited patients, CPB 0093 in the Aetna system is the policy your billing team needs to understand.

Quick-Reference Table

Aetna Open and Low-Field MRI Coverage Criteria and Medical Necessity Requirements 2025

The core position in CPB 0093 Aetna is straightforward: Aetna considers MRI medically necessary based on clinical indication — not on the type of machine used to perform it. Field strength and physical configuration are not determining factors in coverage.

Aetna explicitly recognizes intermediate and low field strength MRI units as an acceptable alternative to standard full-strength scanners. It also covers open MRI units of any configuration, including Stand-Up MRI (imaging performed in a weight-bearing standing position) and seated MRI units. The coverage policy makes no distinction between these and conventional closed-bore high-field scanners.

This matters for your billing team because open MRI billing has historically generated claim denial risk. Some payers treat open or low-field units as inferior substitutes — and deny claims on that basis. Under this coverage policy, Aetna does not take that position. Coverage follows the clinical indication, not the hardware.

That said, "selection criteria must be met" is the qualifier attached to every single CPT code in this policy. Aetna doesn't cover MRI of any type simply because the patient can't tolerate a closed-bore scanner. The underlying medical necessity criteria for the specific MRI study still apply. Meeting the equipment-neutrality standard doesn't bypass the clinical documentation requirements.

Before billing CPT codes like 72141 (cervical spine MRI without contrast), 73721 (lower extremity joint MRI without contrast), or 74181 (abdominal MRI without contrast) on an open or low-field unit, confirm the clinical documentation supports medical necessity for that specific study. Aetna's prior authorization requirements for MRI studies generally haven't changed — check the member's plan for prior auth requirements, because this policy update doesn't eliminate them.

One flag worth raising: the policy lists ICD-10 codes specific to cervical disc disorders (M50.0 through M50.93) and spinal stenosis (M48.02) as diagnosis codes tied to covered indications, along with Ehlers-Danlos syndrome (Q79.60–Q97.69). If you're billing open or positional MRI for lumbar or thoracic pathology, those diagnosis codes are not listed here. That doesn't mean those are excluded — but it does mean your documentation needs to support the clinical necessity argument independently.

Coverage Indications at a Glance

Aetna Open MRI Billing Guidelines and Action Items 2025

1. Add S8042 to your charge capture if you haven't already.
HCPCS S8042 is the specific code for low-field MRI. If your facility operates low-field equipment and you've been billing only the standard CPT code, you're leaving the most accurate coding on the table. Audit your charge capture for low-field MRI services dating back 90 days and confirm S8042 is being applied where appropriate. Do this before October 15, 2025.

2. Confirm your ICD-10 coding maps to Aetna's listed diagnosis codes for spine MRI.
Aetna's coverage policy for CPB 0093 lists specific ICD-10 codes for cervical indications — M48.02, M50.0 through M50.93, and Q79.60–Q97.69. If you're billing cervical spine MRI (72141, 72142, 72156) for Aetna members, your diagnosis codes should map to this list. Mismatches between your ICD-10 codes and Aetna's covered diagnosis list increase claim denial risk.

3. Document why the open or low-field unit was used — but don't overexplain.
Aetna's coverage policy doesn't require a clinical justification for using an open or low-field unit. Equipment type is not a coverage variable here. That said, the underlying medical necessity for the MRI study itself must be documented. Make sure your referring physician documentation supports the specific clinical indication, not just the equipment choice.

4. Check prior authorization requirements at the plan level before scheduling.
This policy confirms equipment-neutral coverage. It does not suspend prior authorization requirements. Prior auth for MRI is common across Aetna commercial plans, and some managed care products have tighter requirements. Check the member's specific plan before the scan — not after. A prior auth miss will generate a claim denial regardless of how well the equipment neutrality policy applies.

5. Train your front-end staff and schedulers on this policy.
Patients asking "will my insurance cover an open MRI?" or "does Aetna pay for low-field scanners?" can now get a clear answer: yes, under CPB 0093, as long as the underlying study meets medical necessity criteria. Your schedulers and prior auth coordinators should know this policy by name. It will come up when verifying benefits for claustrophobic patients, bariatric patients, and patients with implants that restrict bore access.

6. Review your open MRI reimbursement rates against standard MRI rates.
Aetna's policy confirms coverage parity by configuration — but it does not guarantee fee schedule parity. Your contracted reimbursement rate for MRI services may differ between facility types or machine types depending on how your contract is structured. Pull your Aetna EOBs for open MRI claims from the last six months and compare reimbursement against your contracted rates for the same CPT codes on closed-bore equipment. If there's a gap, that's a contracting conversation, not a billing error.

CPT, HCPCS, and ICD-10 Codes for Open and Low-Field MRI Under CPB 0093

Covered CPT Codes (When Selection Criteria Are Met)

Covered HCPCS Codes (When Selection Criteria Are Met)

Key ICD-10-CM Diagnosis Codes