Guideline-based prior authorization and review

UnitedHealthcare uses guideline-based review for advanced imaging and related procedures; providers should expect that requests will be evaluated against these clinical guidelines and Ohio Administrative Code requirements, and that the plan may update guidelines annually. Clinical trial or research imaging will be reviewed for consistency with the guidelines and medical necessity.

CPT listing does not equal PA requirement

Inclusion of a CPT code in these guidelines does not by itself mean the code requires prior authorization; prior authorization requirements are set separately by the payer.

Prior authorization may be required for 3D rendering

Providers may be required to obtain prior authorization for 3D rendering services (CPT 76376, 76377) and certain preoperative 3D planning services (C8001) even when the base imaging or ultrasound does not require authorization.

SPECT/CT coding and management

Report hybrid SPECT/CT using CPT 78830–78832 (and CPT 78072 for SPECT/CT parathyroid). Follow the applicable condition-specific guideline sections for management and any payer prior authorization rules.

Reporting / coding requirements for whole-body MRI and PET/MRI

When PET/MRI is approved, report PET whole-body (CPT 78813) plus MRI unlisted (CPT 76498). Whole‑body MRI is reportable only with CPT 76498 when permitted. Providers must follow coding instructions when requesting PET/MRI or WBMRI.

Prior authorization / documentation expectations

Submit adequate clinical information to establish medical necessity: detailed history, physical exam (including neurologic exam when relevant), appropriate labs, and prior imaging. Condition-specific sections may require additional documentation.

Prior authorization: advanced imaging/3D rendering and brain/orbit MRI

Follow payer prior‑authorization processes where applicable for advanced imaging and 3D rendering (CPT 76376/76377) and for brain/orbit MRI (CPTs 70540/70543/70551/70553) when these are requested in specified clinical scenarios.

Imaging CPTs referenced

The guideline lists the CPT codes addressed (e.g., multiple MRI, CT, PET, and 3D rendering codes); inclusion in the guideline is informational but does not itself define PA rules—verify payer-specific authorization requirements.

Prior authorization expectation for listed imaging procedures

Providers should expect prior authorization to be required per payer rules for the imaging procedures listed when clinical indications or required documentation are not provided to demonstrate medical necessity.

Prior authorization / coverage linkage

Covered imaging codes are linked to medical necessity criteria; ensure documentation of relevant clinical findings (red flags, suspected neurosarcoid, stroke, or surgical planning) is submitted to support coverage.

Prior authorization for PET imaging

Prior authorization is required when ordering Amyloid PET (CPT 78814/78811) or FDG PET (CPT 78608) for MCI/dementia evaluation according to the listed clinical criteria and for imaging related to amyloid‑reducing medications.

Prior authorization — dementia-related imaging

Specialized PET, SPECT, MRI, or CT for dementia indications generally requires prior authorization and must be accompanied by documentation that coverage criteria are met (diagnosis, testing results, prior structural imaging, duration of decline).

Amyloid PET prior authorization requirement

Amyloid Brain PET (CPT 78811 or 78814) for baseline confirmation or treatment monitoring is medically necessary only when amyloid-therapy eligibility criteria are met; follow-up amyloid PET is limited to no more often than once every 6 months.

Neuroimaging for seizures

MRI Brain (CPT 70551/70553) or CT Head (CPT 70450) for seizure evaluation is medically necessary when specified clinical indications are present; prior authorization may be required if clinical indications are not documented.

Prior authorization/ordering clinician requirement for PET/MRI

PET/MRI (MRI CPT 70551 or 70553 co‑registered with FDG‑PET CPT 78608) is medically necessary for pre‑surgical evaluation of refractory seizure only when requested by a neurosurgeon or neurologist or a provider in consultation with them.

Prior authorization: clinical-support requirement

Prior authorization expectations are not numerically specified in the guideline text; however, imaging requests should be supported by the stated clinical criteria and documentation to be considered medically necessary.

Stepwise imaging approach

When clinically appropriate, begin with less invasive, lower-cost imaging (plain film, CT, MRI, US) before advanced modalities; advanced imaging should be justified by the clinical presentation and expected impact on management.

PET/MRI substitution rule

PET/MRI is allowed when PET/CT criteria are met, PET/CT is unavailable at the treating institution, and the provider requests PET/MRI in lieu of PET/CT; report allowed PET/MRI as CPT 78813 + 76498.

Imaging after conservative therapy failure

For consideration of microvascular decompression in hemifacial spasm after failed conservative medical management, add vascular imaging (MRA or CTA) to evaluate vascular anatomy for surgical planning.

Step/sequencing considerations

FDG‑PET combined with MRI may be considered on a case‑by‑case basis at centers that perform FDG‑PET/MRI with standardized protocols; FDG‑PET alone for many dementia types is generally not supported.

Single-modality requirement for NPH

For suspected Normal Pressure Hydrocephalus (NPH), obtain only a single initial modality (CT Head CPT 70450 OR MRI Brain CPT 70551); MRI is preferred if pre‑surgical planning is anticipated.

Transitioning between amyloid-targeting therapies

When transitioning between amyloid-targeting monoclonal antibodies, respect drug half-lives; individuals should be off the prior drug for approximately five half‑lives (examples and recommended intervals provided in the guideline).

Imaging sequence guidance

If CT Head was performed for initial evaluation of new‑onset seizure, MRI may be requested subsequently for additional evaluation; MRI is preferred when available.

Step therapy (not specified)

No formal step‑therapy sequencing (e.g., mandatory trial of conservative care before imaging) is specified; selection of modality is guided by clinical presentation and condition‑specific criteria.

Requests evaluated under Ohio Administrative rules

Requests for services deemed unproven or subject to coverage/quantity limits will be evaluated for medical necessity using Ohio Administrative Code 5160-1-01.

Required clinical documentation

Submit adequate clinical documentation with requests: detailed history, physical exam (including neurologic exam when relevant), pertinent labs, and prior imaging; condition‑specific sections list additional required documentation.

Clinical history and prior imaging review

Review and include prior imaging and diagnostic test results with the request; document the clinical history showing the indication and how the imaging is expected to affect management.

Documentation for 3D rendering supervision

When billing CPT 76376 or 76377, document concurrent physician supervision/participation in the reconstruction process (design of reconstruction, tissues/structures to display, images archived, and monitoring of the 3D product).

Guidance on unlisted codes documentation

When using unlisted CT/MR procedure codes (76497/76498), include documentation describing the procedure, justification, and why no anatomic site‑specific code applies (e.g., navigation, custom planning, special acquisition).

Outside study interpretation billing guidance

When interpreting an outside study, bill CPT 76140 and document that the images were completed elsewhere and a secondary interpretation is requested; do not use a diagnostic imaging code for an outside-study interpretation.

Clinical evaluation required

A pertinent clinical evaluation (detailed history and physical including neurologic exam when relevant) and appropriate laboratory studies must be performed and documented prior to advanced imaging, unless an accepted exception (e.g., guideline‑supported scheduled follow-up) applies.

Record orbital trauma history and prior imaging

Record history of orbital trauma and any prior imaging when requesting orbital/orbit‑clearing studies; plain x‑ray orbit (2 views) or radiologist review of prior CT/MR since the event is required to clear the orbit for MRI.

Required clinical documentation for acute presentations

For acute or worsening mental status change, document onset/duration and perform a bedside neurologic exam including mental status; imaging is medically necessary only after these assessments are documented.

Red-flag documentation required

For Bell's palsy, document presence of 'red flag' features (examples listed in guideline such as trauma, history of tumor/cancer/HIV/Lyme, no improvement at 8 weeks, no full recovery at 3 months, vertigo/hearing loss, bilateral involvement); absent documentation of red flags risks denial.

Required documentation for cognitive decline

Document detailed history of cognitive decline (confirmed by family/others when indicated), neurocognitive testing results, date of onset (≥6 months for dementia criteria), and baseline structural imaging when requesting dementia-related imaging.

Documentation to support dementia-related imaging

When imaging to support amyloid‑targeting therapy eligibility or monitoring, document diagnosis (MCI or mild dementia due to AD), ordering clinician specialty (neurologist/geriatric psychiatrist/geriatrician), duration of cognitive change (≥6 months), baseline MRI availability, and bedside cognitive exam scores meeting required thresholds.

Documentation expectations for amyloid therapy imaging

For amyloid‑therapy imaging, document cognitive exam scores consistent with MCI/mild AD (examples: MMSE not <20; MoCA not <17; SLUMS not <20), and baseline MRI demonstrating absence of intracerebral hemorrhage or vasogenic edema prior to treatment.

Clinical authorization context for pre-surgical epilepsy imaging

For pre‑surgical epilepsy imaging (PET/MRI, MEG co-registration, ictal SPECT, fMRI), requests should be supported by documentation that the request is from or in consultation with a neurosurgeon or neurologist involved in surgical planning.

Required clinical documentation for focal neurologic signs

Document focal neurologic signs or other clinical features that justify advanced imaging (e.g., trigeminal neuralgia, glossopharyngeal neuralgia, focal deficits) to support the modality choice and medical necessity.

Research and investigational imaging denial risk

Imaging requests inconsistent with established clinical standards, requested for research/data collection only, or for investigational/unproven services risk denial as not medically necessary.

Overutilization denial risk

Requests for duplicate, repeat, or questionably necessary imaging—especially without evidence of progression, recurrence, or expected impact on management—may be denied for overutilization.

Risk of denial for duplicate/unnecessary imaging

Repeat or pre‑operative imaging may be denied if not supported by evidence of disease progression, recurrence, or if the surgery/procedure itself is not medically necessary.

WBCT screening denial

Whole‑body CT / LifeScan screening of asymptomatic individuals is not a covered benefit and may be denied if submitted for screening purposes.

Clinical evaluation requirement (denial risk)

Lack of a documented pertinent clinical evaluation, including detailed history and neurologic exam since onset or change in symptoms, may lead to denial unless an accepted exception applies.

Prior GI evaluation required for MRI in nausea/vomiting

For persistent unexplained nausea/vomiting, MRI Brain (CPT 70551 or 70553) is described as medically necessary only after a negative GI evaluation; absence of that prior evaluation could trigger denial.

Documentation prerequisite for acute mental status change imaging

For acute or worsening mental status change, imaging is medically necessary only after a detailed history and bedside neurologic exam including mental status evaluation; missing these documented assessments may trigger denial.

Red-flag documentation required for Bell's palsy

For Bell's palsy, failure to document red-flag features may lead to denial because imaging is not medically necessary in typical Bell's palsy without red flags.

Imaging not appropriate for SCD with normal testing

Advanced imaging is not medically necessary for subjective cognitive decline with normal cognitive testing; ordering advanced imaging in that scenario risks denial.

Perfusion PET exclusion

Perfusion PET Brain (CPT 78609) is explicitly not medically necessary in the evaluation of dementia and may be denied if submitted for that indication.

Denial risk for amyloid PET without eligibility documentation

Requests for amyloid PET, MRI, or CT that do not meet documented eligibility criteria for amyloid‑reduction therapy evaluation or monitoring (e.g., missing diagnosis, ordering specialist, baseline MRI, cognitive scores, or interval limits) are at risk for denial.

Not medically necessary advanced post-processing

Volumetric/quantitative MRI analyses (CPT 0865T/0866T) and 3D rendering (CPT 76376/76377) are considered not medically necessary for many dementia and epilepsy evaluations; requests for these services for those sole purposes risk denial.

Denial triggers for headache without red flags

Advanced imaging for primary headache disorder without focal neurological deficits or red flags, newly diagnosed migraine/tension‑type headache with normal neurologic exam, or chronic stable headache with no neurologic deficit is not medically necessary and may be denied.