Summary & Overview
CPT 70555: Functional MRI of the Brain
CPT code 70555 represents functional MRI (fMRI) of the brain, an advanced diagnostic imaging service that maps brain activity by measuring metabolic and hemodynamic responses to neural stimuli. fMRI is clinically important for pre-surgical planning, research protocols, and evaluation of neurologic and psychiatric conditions where localization of functional areas affects care. Nationally, coverage and utilization of fMRI influence access to specialized neuroimaging and multidisciplinary clinical workflows.
Key payers considered in this overview include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Coverage policy and reimbursement practices vary across commercial plans and Medicare, affecting availability in hospital outpatient departments and dedicated imaging centers.
Readers will find a concise explanation of the clinical and service context for 70555, typical sites of service, and which payers are included in the analysis. The publication summarizes benchmark metrics, common billing modifiers, and policy considerations relevant to fMRI services, and provides clinical context that clarifies when this procedure is used. Data not available in the input will be noted where applicable.
Billing Code Overview
CPT code 70555 describes functional magnetic resonance imaging (fMRI) of the brain, a diagnostic imaging procedure that tracks regional brain activity by assessing metabolic and hemodynamic changes in response to neural activity. The procedure requires the presence of a physician or psychologist to administer and interpret task-based or stimulus-driven imaging sequences.
Service type: Diagnostic functional MRI (neuroimaging) with physician/psychologist administration and interpretation
Typical site of service: Hospital outpatient imaging center or specialized radiology/neuroimaging clinic, where MRI scanners and clinical staff are available to perform task-based studies and supervise patient performance.
Clinical & Coding Specifications
Clinical Context
A 45-year-old right-handed patient with focal seizures of suspected temporal lobe origin is referred by a neurologist for functional MRI of the brain to map language and motor cortex prior to possible epilepsy surgery. The clinical workflow begins with physician or psychologist review of the indication and selection of task paradigms (language, motor, sensory). The patient is screened for MRI safety, consented, and instructed on task performance (for example, verb generation, finger tapping). A technologist performs the MRI sequences while a physician or psychologist is present to administer and monitor the functional tasks and patient responses. Data processing and interpretation by the attending physician include identification of eloquent cortex to guide surgical planning; a report documents task paradigms, quality of activation maps, and clinical correlation. Typical site of service is an outpatient hospital imaging center or ambulatory surgical center with MRI capability; inpatient settings are also possible when evaluation is inpatient for pre-surgical assessment.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the physician’s interpretation/reading portion separate from technical imaging. |
TC |