Summary & Overview
HCPCS C9791: Chest MRI with Inhaled Hyperpolarized Xenon-129 Contrast Agent
HCPCS Level II code C9791 designates a specialized chest magnetic resonance imaging (MRI) procedure using inhaled hyperpolarized xenon-129 as the contrast agent, including preparation and administration of the agent. This code captures an advanced pulmonary imaging technique that offers high-resolution functional and structural assessment of the lungs, potentially informing diagnosis and monitoring of respiratory and interstitial lung diseases. Its introduction reflects growing clinical interest in functional lung MRI and the use of novel inhaled contrast agents.
Key payers in the national landscape include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context and service setting, summaries of payer coverage considerations where available, and reference benchmarks and policy updates relevant to adoption and billing of this advanced imaging service. The content outlines typical sites of service and the core elements represented by the code: imaging acquisition plus preparation and administration of the inhaled xenon-129 agent.
The publication provides practical information on how the code is used in claims, notes common modifier activity when present, and situates the code within broader trends in pulmonary imaging. Data elements not provided in the input are identified as unavailable. The focus is national in scope and intended for policy analysts, billing professionals, and clinical leaders tracking adoption of advanced pulmonary MRI techniques.
Billing Code Overview
HCPCS Level II code C9791 describes magnetic resonance imaging with inhaled hyperpolarized xenon-129 contrast agent, chest, including preparation and administration of agent. The service type is diagnostic chest MRI with an inhaled contrast agent. The typical site of service is hospital outpatient imaging departments and advanced imaging centers where magnetic resonance imaging with specialized inhaled contrast and monitored administration can be performed.
Data not available in the input.
Clinical & Coding Specifications
Clinical Context
A 62-year-old current or former smoker with progressive exertional dyspnea and unexplained diffusion impairment is referred for advanced pulmonary imaging. The patient has baseline pulmonary function testing showing reduced DLCO and previous high-resolution chest CT without definitive explanation for gas-exchange abnormality. The referring pulmonologist orders magnetic resonance imaging of the chest using inhaled hyperpolarized xenon-129 to evaluate regional ventilation and gas-exchange abnormalities.
The clinical workflow: the patient arrives at an outpatient imaging center or hospital radiology department. Pre-procedure screening includes confirmation of indications, informed consent specifically for inhaled contrast, review of allergy and pregnancy status, and assessment of ability to perform breath holds. A respiratory therapist or nuclear medicine technologist prepares and administers the hyperpolarized xenon-129 gas per institutional protocol while an MRI technologist and radiologist perform the chest MRI sequences. Monitoring of oxygen saturation and patient tolerance occurs throughout. Images are acquired, reconstructed, and interpreted by a thoracic radiologist with correlation to prior PFTs and CT. Post-procedure observation is brief; the patient is discharged once stable.
Typical site of service: outpatient imaging center or hospital outpatient radiology department.
Typical patient scenario: evaluation of interstitial lung disease, chronic obstructive pulmonary disease phenotypes, small airways disease, or unexplained diffusion impairment to characterize regional ventilation and alveolar-capillary gas-exchange using C9791.
Coding Specifications
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