Loading...

    Explore
    • Policy Monitoring
    • Live Policy Feed
    • Billing Codes
    • NPI Medicare & Medicaid
    • Healthcare Providers
    • Health Insurance Payers
    • States
    • Service Lines
    • Taxonomy Codes
    Lookup tools
    • Billing Code Lookup
    • CPT Modifier Lookup
    • Provider Taxonomy Code Lookup
    • Healthcare Provider & Facility Lookup
    • Health Insurance Payer Lookup
    • Payer Contact Directory

    Policy & Benchmark Tools

    • Prior Authorization Lookup
    • Coverage Criteria Lookup
    • Timely Filing Lookup
    • Billing Code Reimbursement Rates
    • Payer Comparison Dashboard
    • Facility Comparison Dashboard
    • All tools

    Company

    • About OpenPayer
    • Data Sources
    • Trek Health
    OpenPayerby Trek Health
    LinkedInYouTube

    © 2026 Trek Health. All rights reserved.

    OpenPayer is built and maintained by Trek Health.

    v1.0.30
    OpenPayerBilling CodesDiagnostic Nuclear Medicine Procedures on the Nervous SystemCPT cpt-78635-csf-flow-ventricular-imaging-hydrocephalus
    Ask Trek AI about this page

    CPT 78635: CSF Flow Study for Ventricular Assessment

    Medicare pays $205 on average nationally for this procedure.

    CPT code 78635 describes a diagnostic cerebrospinal fluid (CSF) flow imaging study used to assess ventricular size and CSF dynamics, most commonly performed to evaluate hydrocephalus; the service is an imaging diagnostic study typically performed in an outpatient radiology or pediatric specialty imaging setting and may involve neuroimaging techniques to visualize CSF flow and ventricular anatomy.

    For related coverage guidance, see recent payer policy updates: Clinical Review Criteria Intraoperative Neurophysiological Monitoring (IONM), Remote Electrical Neuromodulation for Migraines (i.e., Nerivio®), Lumbar Microdiscectomy.

    Customize your policy alerts

    Sign up for cpt 78635 policy alerts

    Get alerted when payer policies referencing 78635 are released or updated.

    Monitor payer policy activity

    Receive email alerts as soon as relevant payer policies are published or updated.

    Table of contents

    Progress1 / 6

    Explore openpayer tools

    • Billing CodesCPT, HCPCS, DRG & more
    • Reimbursement RatesCommercial vs. Medicare rate reports
    • Facility ComparisonBeds, revenue & payer mix
    • ProvidersHospitals & facilities
    • PayersPlans & market footprint
    • Taxonomy CodesNUCC specialty codes
    • ModifiersCPT modifiers & usage
    • Prior AuthorizationPA policies by payer & drug
    • Timely FilingFiling deadlines by payer
    • Coverage CriteriaMedical necessity by payer
    • Payer ContactsClaims, PA & appeals contacts
    View all tools

    Clinical & Coding Specifications

    Clinical Context

    A typical patient is an infant or child referred to pediatric neuroradiology for evaluation of suspected hydrocephalus or shunt malfunction. The child presents with increasing head circumference, vomiting, lethargy, bulging fontanelle, or changes in neurologic status. The clinical workflow begins with a neurosurgical or pediatrician referral. On arrival, the patient is assessed for stability, history of prior ventriculoperitoneal shunt placement is confirmed, and informed consent is obtained from the parent or guardian. The procedure, 78635 (CSF flow study / cine phase-contrast MRI of CSF dynamics), is performed in the MRI suite with pediatric monitoring; sequences are acquired to visualize cerebrospinal fluid flow through the cerebral aqueduct and ventricles. Images are reviewed by the radiologist to assess ventricular size, flow jets, and evidence of obstruction or shunt patency. Findings are communicated to the referring neurosurgeon or pediatrician for further management, which may include surgical revision, shunt tap, or clinical observation. Typical site of service is an outpatient or hospital-based radiology department; the service type is diagnostic neuroradiology imaging.

    Related CPT Codes

    CPT CodeDescriptionRelationship to This Procedure
    70551Magnetic resonance imaging, brain, without contrast, including diffusion, with or without spectroscopy; routine diagnostic brain MRIPerformed before or alongside CSF flow study to evaluate brain anatomy and ventricular size.
    70553Magnetic resonance imaging, brain, without and with contrast, followed by contrast-enhanced sequencesUsed when additional contrast-enhanced evaluation of intracranial pathology is required in the same session.
    77290Magnetic resonance (MR) guidance for interventional procedure; planning, real-time guidance, and controlOccasionally related when image guidance is used for shunt tap or reservoir access following imaging findings.
    99152Moderate sedation services provided by the same physician performing a diagnostic or therapeutic service (initial 15 minutes)Used when moderate sedation is required for pediatric patients to tolerate MRI sequences.
    G0250Moderate sedation services provided by a physician other than the proceduralist (first 15 minutes)Billed when anesthesia or sedation services are provided separately for the MRI study.

    Related Modifiers

    5 rows

    ModifierDescriptionWhen to Use
    26Modifier 26 (Professional Component) identifies and bills only the professional portion of a split service — the physician’s interpretation, report, and medical judgment — when the technical…- Use CPT Modifier -26 when you are billing only the professional component (PC) of a split‑bill eligible service—i.e., you performed the physician interpretation, medical judgment and prepared a…
    52Modifier ‑52 (Reduced Services) indicates that a service or procedure was partially reduced or omitted at the provider’s discretion, allowing reporting of the basic procedure number with a qualifier…- Use modifier -52 when a physician or qualified health professional electively reduces or omits part of a procedure or service (for example, performing fewer required views or omitting a portion of…
    53Modifier 53 (Discontinued Procedure) signals that a surgical or diagnostic service was begun by the physician but terminated because of extenuating circumstances that threatened the patient’s…- Use modifier -53 when a physician/qualified healthcare professional has started a surgical or diagnostic procedure (e.g., anesthesia administered, incision or scope insertion) and then discontinues…
    76Modifier -76, Repeat Procedure or Service by Same Physician or Other Qualified Health Care Professional, is appended when the same provider performs an identical, medically necessary procedure or…- Use modifier -76 when the same physician or other qualified health care professional performs an identical procedure or service a second (or subsequent) time on the same date of service and the…
    63Modifier‑63 is appended to surgical CPT codes (20000–69990) when a procedure is performed on a neonate or infant weighing ≤ 4 kg (about 8.8 lbs). The AMA/AAPC definition specifies this use and notes…- Use modifier -63 only for surgical procedures in the CPT 20000–69990 series performed on a neonate or infant who weighs ≤ 4 kg at the time of the procedure; it indicates increased complexity due to…

    Related Provider Taxonomies

    8 rows

    Taxonomy Code
    2085R0202X
    2084P0800X
    367500000X
    207RH0000X
    3336N0007X
    176B00000X
    224L00000X
    261QA0900X

    Related Payer Policy Updates

    Specialty: Neurology/Neurosurgery1 / 2

    10 rows

    PolicyPayerEffective Date
    Clinical Review Criteria Intraoperative Neurophysiological Monitoring (IONM)Kaiser Permanente2027-01-01
    Remote Electrical Neuromodulation for Migraines (i.e., Nerivio®)bcbsvermont2026-11-01
    Lumbar Microdiscectomyuniverahealthcare2026-10-15
    Artificial Cervical Intervertebral Discuniverahealthcare2026-10-15
    Lumbar Decompressionuniverahealthcare2026-10-15
    Responsive Neurostimulation for Focal EpilepsyPremera Bluecross2026-10-14
    Intraoperative MonitoringProvidence Health Plan2026-10-01
    Intraoperative MonitoringProvidence Health Plan2026-10-01
    High-Intensity Focused UltrasoundMass General Brigham Health Plan2026-10-01
    Vagal Nerve StimulationAmbetter Nevada2026-10-01

    Related Codes

    CPT-78600-BRAIN-NUCLEAR-STATIC-IMAGING-FEWER-THAN-FOUR-VIEWS

    CPT 78600: Nuclear Diagnostic Brain Imaging, <4 Static Views

    CPT-78601-BRAIN-NUCLEAR-PERFUSION-IMAGING-FEWER-THAN-FOUR-STATIC-VIEWS

    CPT 78601: Nuclear Diagnostic Brain Imaging, Static Views and Flow

    CPT-78605-BRAIN-NUCLEAR-STATIC-IMAGING-FOUR-OR-MORE-VIEWS

    CPT 78605: Brain Nuclear Diagnostic Imaging, Four+ Static Views

    CPT-78606-NUCLEAR-BRAIN-IMAGING-STATIC-VIEWS-CEREBRAL-BLOOD-FLOW

    CPT 78606: Brain Nuclear Imaging, Static Views with Flow Evaluation

    CPT-78608-PET-BRAIN-METABOLIC-IMAGING

    CPT 78608: Brain PET for Cerebral Metabolic Imaging

    CPT-78609-PET-BRAIN-IMAGING

    CPT 78609: Brain PET Scan for Function and Perfusion

    CPT-78610-CEREBRAL-PERFUSION-NUCLEAR-MEDICINE-STUDY

    CPT 78610: Brain Perfusion Study with Gamma Tracer

    CPT-78630-CSF-FLOW-STUDY-HYDROCEPHALUS-LEAK-EVALUATION

    CPT 78630: Cerebrospinal Fluid (CSF) Flow Study, Head

    CPT-78645-CSF-SHUNT-FLOW-IMAGING

    CPT 78645: CSF Shunt Patency and Flow Imaging Study

    CPT-78650-CSF-LEAK-NUCLEAR-IMAGING-LOCALIZATION

    CPT 78650: Nuclear Medicine Localization of CSF Leak

    Showing 1–10 of 12

    Frequently Asked Questions

    References

    1. 1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
    2. 2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
    3. 3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.
    Published by

    Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

    Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.