Cerebral Perfusion Studies — CPB 0663 | AETNA Coverage Update

TL;DR: Aetna, a CVS Health company, modified CPB 0663 governing cerebral perfusion studies, effective February 27, 2026. Here's what billing teams need to know about covered indications, a long list of exclusions, and which codes are in play.

This update to the Aetna cerebral perfusion coverage policy draws a hard line between acute stroke imaging and everything else. CPT codes 0042T, 70472, and 70473 sit at the center of the covered column — but only for a narrow set of indications. The experimental and investigational list runs 33 items long across CT and MRI perfusion, which means your denial exposure is real if your physicians order outside those covered indications.

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Quick-Reference Table

Field	Detail Copy
Payer	Aetna, a CVS Health company
Policy	Cerebral Perfusion Studies — CPB 0663
Policy Code	CPB 0663
Change Type	Modified
Effective Date	February 27, 2026
Impact Level	High
Specialties Affected	Neurology, Neuroradiology, Radiology, Neurosurgery, Emergency Medicine
Key Action	Audit your cerebral perfusion orders against the covered indication list before billing CPT 0042T, 70472, or 70473 for any Aetna member

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Aetna Cerebral Perfusion Studies Coverage Criteria and Medical Necessity Requirements 2026

CPB 0663 Aetna covers two categories of cerebral perfusion imaging under specific medical necessity criteria. If your claim doesn't match one of these categories, expect a denial.

CT perfusion studies (CPT 0042T, 70472, 70473) are medically necessary for:

The 24-hour window for acute ischemic stroke is not a soft guideline. It's a hard coverage boundary. A CT perfusion study ordered on hour 25 is a different conversation with your payer — plan accordingly.

MRI perfusion studies — diffusion-weighted or perfusion-weighted — are medically necessary for one indication only: evaluation of acute cerebral ischemia.

Here's the rule that will catch teams off guard: billing both CT perfusion and MRI perfusion for the same acute ischemic stroke encounter is not medically necessary. Aetna considers that redundant. If your facility routinely runs both modalities on stroke patients, you need to review that workflow before submitting claims.

Prior authorization requirements are not spelled out explicitly in this version of the policy, but given the scope of the experimental/investigational list, verify prior auth requirements with Aetna directly for any CPB 0663 cerebral perfusion billing — especially for MRI perfusion. Your contracts may require it.

Reimbursement for covered studies depends entirely on meeting these narrow criteria. Document the indication, the timing (for ischemic stroke), and the modality choice in your clinical notes. That documentation is what keeps a clean claim clean through audit.

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Aetna Cerebral Perfusion Studies Exclusions and Non-Covered Indications

This is the section that matters most for claim denial prevention. Aetna's experimental and investigational list for CPB 0663 is long and specific. These aren't edge cases — several are indications that clinicians order regularly.

For CT perfusion studies, Aetna considers these not covered:

The subarachnoid hemorrhage item deserves a flag. Delayed cerebral ischemia from vasospasm is a real clinical concern after SAH, and many neurocritical care teams use CT perfusion to guide management. Aetna doesn't cover it. If your neurosurgeons or intensivists order this routinely, the claim denial will follow.

For MRI perfusion studies, Aetna considers these not covered:

Items 3, 4, 5, and 8 are the high-exposure ones. Neuro-oncology teams order MRI perfusion for glioma management constantly — to distinguish recurrence from pseudo-progression, to grade tumors, to evaluate treatment response. Every one of those scenarios is excluded under this coverage policy.

If your oncology or neuroradiology teams bill MRI perfusion for any glioma-related indication, audit those claims against this list now — before February 27, 2026.

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Coverage Indications at a Glance

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Aetna Cerebral Perfusion Studies Billing Guidelines and Action Items 2026

These are the specific steps your billing and clinical teams should take before and after the February 27, 2026 effective date.

Copy Action Items

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CPT, HCPCS, and ICD-10 Codes for Cerebral Perfusion Studies Under CPB 0663

Covered CPT Codes (When Selection Criteria Are Met)

Code	Type	Description Copy
0042T	CPT	Cerebral perfusion analysis using computed tomography with contrast administration, including post-processing
70472	CPT	Computed tomographic (CT) cerebral perfusion analysis with contrast material(s), including image post-processing
70473	CPT	Computed tomographic (CT) cerebral perfusion analysis with contrast material(s), including image post-processing

Other CPT Codes Related to CPB 0663

These codes are referenced in the policy but are not themselves the primary covered perfusion codes. They appear in the context of related procedures or experimental indications.

HCPCS Codes Related to CPB 0663

Code	Type	Description Copy
C9257	HCPCS	Injection, bevacizumab, 0.25 mg
J9035	HCPCS	Injection, bevacizumab, 10 mg

Note: These bevacizumab codes appear in the context of the MRI perfusion exclusion for glioblastoma treatment response assessment.

Key ICD-10-CM Diagnosis Codes Referenced in CPB 0663

The full code list runs 207 entries. Below are the clinically significant groupings tied to covered and excluded indications.

Code	Description	Coverage Context Copy
B00.4	Herpesviral encephalitis	Excluded — experimental for CT perfusion
C00.0–C14.8	Malignant neoplasm of lip, oral cavity, and pharynx	Excluded — head and neck cancers, experimental for MRI perfusion
C34.0–C34.x	Malignant neoplasm of bronchus and lung	Excluded — lung cancer differentiation is experimental for CT perfusion

Your ICD-10 coding on cerebral perfusion claims must match the covered indication. Coding an excluded diagnosis — even if the physician notes support it — will trigger the experimental designation and a denial.

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