CMS FDG PET Coverage for Dementia: What Billing Teams Need to Know About NCD 288 (2026)

The Centers for Medicare & Medicaid Services has issued a modification to National Coverage Determination (NCD) 288, governing FDG Positron Emission Tomography coverage for dementia and neurodegenerative diseases, effective March 12, 2026. For billing teams serving neurology, nuclear medicine, and radiology practices, this policy dictates exactly when Medicare will—and won't—pay for FDG PET scans used in differentiating Alzheimer's disease (AD) from fronto-temporal dementia (FTD). Understanding the precise medical necessity criteria in NCD 288 is essential to avoiding denials on these high-cost diagnostic studies.

CMS FDG PET Coverage Under NCD 288: What the Policy Actually Covers

CMS covers FDG PET scans for dementia under two distinct pathways. The first is the differential diagnosis of fronto-temporal dementia versus Alzheimer's disease, subject to a specific set of clinical requirements. The second is participation in a CMS-approved practical clinical trial focused on the utility of FDG PET in diagnosing or treating dementing neurodegenerative diseases.

Most billing situations will fall under the first pathway. If a patient doesn't fit the clinical criteria for FTD-versus-AD differentiation, coverage via a qualifying clinical trial is the only other Medicare-recognized route. This distinction matters when your ordering physician is using FDG PET for a broader neurodegenerative workup—that use case is not independently covered under NCD 288.

Medical Necessity Criteria for CMS FDG PET Reimbursement: All Seven Requirements

This is where most claims fall apart. CMS requires that all of the following conditions be met and documented before an FDG PET scan is considered reasonable and necessary for AD/FTD differential diagnosis.

1. Recent dementia diagnosis with documented cognitive decline of at least six months. The patient must meet diagnostic criteria for both AD and FTD simultaneously—meaning the clinical picture is genuinely ambiguous between the two.

2. FTD must be a suspected alternative cause. Specific early-presenting symptoms of FTD must be present: social disinhibition, social awkwardness, language difficulties, or loss of executive function. These symptoms distinguish FTD from the memory-loss-predominant presentation of AD and must be documented in the chart.

3. Comprehensive clinical evaluation per AAN standards. This means a full medical history (including information from a well-acquainted informant), assessment of activities of daily living, physical and mental status examination, formal documentation of cognitive decline over at least six months using cognitive scales or neuropsychological testing, laboratory tests, and structural imaging—either MRI or CT.

4. Evaluation by a dementia-experienced physician. The workup must be conducted by a physician with demonstrated experience in dementia diagnosis and assessment. Referring providers should note this qualification explicitly in documentation.

5. The evaluation did not yield a definitive diagnosis. After the comprehensive workup above, the specific neurodegenerative disease or causative factor must remain uncertain. The FDG PET must be reasonably expected to help clarify the diagnosis and guide treatment.

6. Facility and reader qualifications. The scan must be performed at a facility with all required accreditation for nuclear medicine equipment. The interpreting physician must be an expert in nuclear medicine, radiology, neurology, or psychiatry with specific experience reading dementia-related scans.

7. No prior SPECT or FDG PET for the same indication. If a brain SPECT or FDG PET has already been performed for the same clinical question, a repeat study is not covered—with two exceptions. A repeat scan may be covered if the patient has shown important changes in the scope or severity of cognitive decline (and still meets all other criteria), or if the prior SPECT results were inconclusive or difficult to interpret due to inadequate technology. In the latter case, at least one year must have passed since the prior scan was performed.

8. Documentation maintained in the medical record. Both the referring and billing providers must document that they have completed the appropriate evaluation. The date of symptom onset, along with all evaluation elements listed above, must be present in the beneficiary's medical record before the scan is ordered.

What Makes This Policy High-Stakes for Revenue Cycle Teams

FDG PET studies carry significant facility and professional fees. A denial on medical necessity grounds for a study at this cost level has a material impact on revenue—and these denials are rarely overturned without comprehensive documentation assembled before the scan.

The requirement that the patient meet diagnostic criteria for both AD and FTD simultaneously is a common documentation gap. Physicians often note FTD as a "rule-out" rather than explicitly documenting that diagnostic criteria for both conditions are satisfied. That distinction can be the difference between payment and a denial.

Similarly, the prohibition on repeat scanning for the same indication catches billing teams off guard. If a prior SPECT was inconclusive, the chart must explicitly note that, and the claim must demonstrate that 12 months have elapsed since the original study.

Affected Codes

This policy does not list specific CPT or HCPCS codes in the published NCD 288 (288-v3) data. Billing teams should verify the appropriate PET imaging codes with their MAC (Medicare Administrative Contractor), as applicable codes for FDG PET studies may be addressed in local coverage determinations or contractor billing articles that accompany this NCD. Do not assume a specific code is covered without MAC confirmation.

Related ICD-10 Diagnosis Codes — while not enumerated in the NCD itself, claims for this indication will typically require diagnosis codes supporting dementia, Alzheimer's disease, or fronto-temporal dementia. Work with your clinical team and MAC guidance to identify the appropriate ICD-10-CM codes for your patient population.

What Your Billing Team Should Do