Who reviews prior authorization requests for Imaging cerebrospinal fluid flow in the brain and spinal cord's ventricles (CPT 78635)?

Most commercial payers hand imaging reviews to a radiology benefit manager. For the payers tracked here, requests are reviewed using guidelines from eviCore, Carelon, CMS, UnitedHealthcare / eviCore. The request is submitted through that organization's portal rather than the health plan's general line.

What should be in the clinical notes before requesting Imaging cerebrospinal fluid flow in the brain and spinal cord's ventricles (CPT 78635)?

Reviewers look for a recent office visit that documents the symptoms and how long they have lasted, exam findings, results of any earlier imaging, treatments already tried and how the patient responded, and the specific question the study is expected to answer. The diagnosis code on the request should match what the notes describe.

CPT 78635: Imaging cerebrospinal fluid flow in the brain and spinal cord's ventricles - Prior Authorization and Price

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CPT 78635

Imaging cerebrospinal fluid flow in the brain and spinal cord's ventricles.

Nuclear Medicine

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Payer guidelines that apply

Payer	Reviewed using	Guideline	Sections
Aetna	eviCore	Head Imaging Guidelines 2.0.2026, effective Sep 1, 2026 Pediatric Head Imaging Guidelines 2.0.2026, effective Sep 1, 2026	2 that name this code
Anthem BCBS	Carelon	Nuclear medicine imaging effective Sep 19, 2026	4 that name this code
Cigna	eviCore	Pediatric Head Imaging Guidelines 2.0.2026, effective Sep 1, 2026	1 that name this code
Medicare	CMS	—	None found
Original Medicare does not run a prior authorization program for outpatient imaging; claims are judged against the coverage policies above. Medicare Advantage plans set their own prior authorization rules.
UnitedHealthcare	UnitedHealthcare / eviCore	Commercial and Exchange Cardiovascular and Radiology Imaging Guidelines 09.2026, effective Sep 1, 2026	2 that name this code

Guidelines collected from the payers' published documents on September 29, 2026. Payers revise these documents during the year. Open the guideline link to confirm the current version before you submit.

Conditions the guidelines address for this study

These are the clinical situations where payer guidelines discuss Imaging cerebrospinal fluid flow in the brain and spinal cord's ventricles. Each has its own criteria for when the study is considered appropriate.

Brain and spinal cord malignancies Anthem BCBS
Cerebrospinal fluid leak of the skull base Anthem BCBS
Hydrocephalus/ventricular assessment, when MRI cannot be performed or is nondiagnostic Anthem BCBS
Spontaneous (idiopathic) intracranial hypotension, when MRI cannot be performed or is nondiagnostic Anthem BCBS
Macrocephaly, Microcephaly, and Hydrocephalus Aetna · Cigna · UnitedHealthcare
Nuclear Medicine Aetna · UnitedHealthcare

Typical price

Commercial insurance, median

$622

Middle half of rates: $535 to $858

Medicare, hospital outpatient

$555

Facility payment

Medicare, physician fee schedule

$296

National, non-facility

Commercial figures come from negotiated rates published by 447 hospitals; Medicare figures from CMS fee schedules. Rates vary widely by hospital and plan. Pricing data from CenterIQ.

Get notified when the rules for this study change

Payers update imaging guidelines several times a year. We will email you when the criteria for Imaging cerebrospinal fluid flow in the brain and spinal cord's ventricles change.

CPT 78635: Imaging cerebrospinal fluid flow in the brain and spinal cord's ventricles - Prior Authorization and Price

Payer guidelines that apply

Conditions the guidelines address for this study

Typical price

Get notified when the rules for this study change

Frequently asked questions

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