Magnetic Source Imaging/Magnetoencephalography — CPB 0279 | AETNA Coverage Update

Aetna modified CPB 0279 covering magnetoencephalography (MEG) and magnetic source imaging (MSI), effective September 26, 2025. Here's what billing teams need to know.

Aetna, a CVS Health company, updated its MEG/MSI coverage policy under CPB 0279 in the Aetna magnetoencephalography coverage policy. The change affects CPT codes 95965, 95966, and 95967, as well as HCPCS code S8035. If your practice or facility bills MEG or MSI for pre-surgical epilepsy evaluation, this update affects your medical necessity documentation requirements directly.

Quick-Reference Table

Aetna Magnetoencephalography Coverage Criteria and Medical Necessity Requirements 2025

Aetna's coverage policy under CPB 0279 is narrow by design. MEG and MSI are covered for exactly one indication: pre-surgical evaluation in patients with intractable focal epilepsy.

That sounds simple. It isn't.

Aetna requires that the MEG or MSI be ordered specifically to identify and localize areas of epileptiform activity. That's the first bar. The second bar is the real one — discordance must exist, or unresolved questions must remain, from among other localization techniques already performed.

That means you can't bill CPT 95965 as the first-line workup. The patient must have already gone through other localization methods — typically video-EEG monitoring, MRI, PET, SPECT, or neuropsychological testing — and those results must either conflict with each other or leave the surgical team without a clear answer. The MEG fills the gap. That clinical sequence needs to be documented in the chart before you submit.

The medical necessity argument lives in the word "discordance." Your documentation must show what the other studies found, why they disagree or fail to localize the focus, and how MEG adds information that changes the surgical planning. Without that, Aetna will deny on medical necessity grounds.

Prior authorization is strongly recommended before scheduling MEG. While CPB 0279 doesn't use the phrase "prior authorization required" explicitly, MEG is a high-cost, low-volume procedure. Aetna reviews these claims closely. Get prior auth before the study — not after. Chasing reimbursement after a denial on a $3,000+ MEG study is a bad use of your team's time.

For the MEG billing itself, the primary study code is CPT 95965 (spontaneous brain magnetic activity). If the study includes evoked magnetic fields — sensory, motor, language, or visual cortex mapping — you bill CPT 95966 for the first modality and add-on code CPT 95967 for each additional modality. HCPCS code S8035 is the magnetic source imaging equivalent used in some commercial billing contexts. Confirm which code your facility is credentialed to bill before the effective date of September 26, 2025.

Aetna MEG and MSI Exclusions and Non-Covered Indications

The ICD-10 code list in this policy runs 169 codes — and that's where billing teams can get into trouble.

Aetna includes diagnosis codes spanning malignant brain tumors (C71.0–C71.9), Alzheimer's disease (G30.x), Parkinson's disease (G20.x), multiple sclerosis (G35), Huntington's disease (G10), and a broad range of mental and behavioral disorders (F01.50–F99). These codes appear in the policy, but that doesn't mean MEG is covered for all of them.

The covered indication is intractable focal epilepsy for pre-surgical evaluation — full stop. The other diagnosis codes are listed as "other ICD-10-CM codes related to the CPB," which typically means they appear elsewhere in the policy document in the context of non-covered or experimental use.

Billing MEG for a patient with Alzheimer's disease, MS, or a psychiatric diagnosis under this policy will almost certainly generate a claim denial. Aetna does not consider MEG medically necessary for general neurological or psychiatric indications.

The same logic applies to the related surgical CPT codes in this policy — 61697, 61698, 61700, 61702, 61703, 61705, 61708, and 61710. These are intracranial aneurysm and vascular malformation surgery codes. They appear as "other CPT codes related to the CPB." They are not MEG billing codes. Do not use them in MEG claims.

Coverage Indications at a Glance

Aetna MEG Billing Guidelines and Action Items 2025

Here's what your billing team should do before and after the September 26, 2025 effective date.

1. Audit your MEG charge capture for CPT code accuracy.
Confirm your charge description master maps CPT 95965 for spontaneous MEG, CPT 95966 for the first evoked modality, and add-on code 95967 for each additional modality. These three codes are the entire MEG billing set under CPB 0279. If your CDM has them bundled or coded incorrectly, fix that now.

2. Build a documentation checklist for the discordance requirement.
Every MEG claim under this policy needs the same documentation: what prior localization studies were done, what those studies showed, why the results were discordant or inconclusive, and how MEG was ordered to resolve the question. Train your clinical staff to record this in the ordering note — not just in the operative report. Aetna reviewers look at the ordering documentation first.

3. Confirm the ICD-10 codes your team uses for focal epilepsy.
The covered ICD-10 range runs through G40.101–G40.219 and beyond for localization-related epilepsy codes. Review your encounter data for MEG studies over the past 12 months. Make sure the diagnoses on those claims match the intractable focal epilepsy category — not a general epilepsy code and not a non-epilepsy neurological code.

4. Get prior authorization before scheduling the study.
Don't schedule MEG without prior auth in hand. This is a specialty procedure with high per-claim reimbursement exposure. If Aetna denies after the fact, your appeal has to prove both medical necessity and that you followed Aetna's billing guidelines. Starting with prior auth gives you a cleaner record.

5. Don't bill S8035 and CPT 95965 on the same claim.
HCPCS S8035 (magnetic source imaging) and CPT 95965 (MEG recording and analysis) describe the same service. Billing both on the same claim creates a duplicate claim risk. Choose one based on your contract and payer instructions. When in doubt, call Aetna provider services and get it in writing.

6. Flag non-epilepsy MEG orders before they hit billing.
If your neurology or neuroradiology group occasionally orders MEG for other diagnoses — MS, dementia workup, psychiatric evaluation — those claims will not clear Aetna under this coverage policy. Build a hard stop in your billing workflow that requires a focal epilepsy ICD-10 code on any MEG claim before it goes out the door.

If your practice has a high volume of MEG studies or a mixed payer population, talk to your compliance officer before the September 26 effective date. The discordance requirement is specific, and how it plays out in your documentation environment is worth a 30-minute review.

CPT, HCPCS, and ICD-10 Codes for MEG and MSI Under CPB 0279

Covered CPT Codes (When Selection Criteria Are Met)

Covered HCPCS Codes (When Selection Criteria Are Met)

Other CPT Codes Related to CPB 0279 (Not MEG Billing Codes)

Key ICD-10-CM Diagnosis Codes

The table below lists the primary diagnosis codes relevant to MEG billing under CPB 0279. The focal epilepsy G40.x codes are your covered territory. The others appear in the policy but do not support a covered MEG claim.