The Current Procedural Terminology (CPT) system establishes a uniform language for medical services, allowing healthcare providers and insurance companies to communicate accurately about procedures. CPT code 70551 specifically identifies a Magnetic Resonance Imaging (MRI) scan of the brain and brainstem performed without the use of intravenous contrast material. This non-invasive diagnostic tool is part of the Diagnostic Radiology section and is frequently used for initial evaluations before moving to more complex or contrast-enhanced studies.
The Medical Procedure Defined
Magnetic Resonance Imaging uses a powerful magnetic field and radio waves to generate detailed images of the body’s internal structures without exposing the patient to ionizing radiation. The machine measures signals emitted by water molecules in the tissues, which are then processed by a computer to create cross-sectional, high-resolution images of the brain.
The “without contrast” component of CPT 70551 signifies that no gadolinium-based dye is injected into the bloodstream during the procedure. This non-contrast imaging is well-suited for visualizing the basic structural anatomy of the brain and brainstem. It is particularly effective for detecting acute hemorrhage, evaluating the size of the brain’s fluid-filled cavities (ventricles) to check for hydrocephalus, and assessing congenital abnormalities.
The non-contrast study is often the first step in neurological imaging, providing a baseline structural assessment. For comparison, CPT 70553 describes an MRI that is performed first without contrast, and then repeated after contrast administration. The choice to use CPT 70551 indicates that the physician believes sufficient information can be gathered from the structural images alone.
Clinical Reasons for Ordering
A physician orders an MRI of the brain without contrast when the diagnostic question primarily involves structural integrity or when the potential risks of contrast outweigh the benefits. This code is commonly applied when investigating chronic, non-specific headaches where a structural cause is suspected but a tumor or infection is not highly likely. An initial non-contrast study can effectively rule out large structural issues that might be causing the persistent pain.
The non-contrast MRI is also frequently utilized in the initial evaluation of a suspected acute stroke, as it is highly sensitive to the early changes of ischemic stroke and acute bleeding. Furthermore, it is a standard tool for assessing certain seizure disorders, looking for structural abnormalities in the brain that may be the source of the electrical disturbances. CPT 70551 is also used for screening for multiple sclerosis, as the characteristic lesions associated with the disease can often be seen without contrast enhancement.
The decision to forgo contrast is also made when a patient has a known severe allergy to gadolinium agents or when they have significant kidney dysfunction. Gadolinium, the active component in most MRI contrast agents, is processed and eliminated by the kidneys, and its use can be risky for individuals with impaired renal function. In these instances, the non-contrast MRI provides the safest and most appropriate diagnostic approach.
Understanding the Patient Experience
The experience of undergoing the procedure coded as CPT 70551 begins with a thorough safety screening to ensure no metal objects or implants are present that could react dangerously with the strong magnetic field. Patients must remove all jewelry, watches, and items containing metal, as even small objects can be pulled toward the machine. Patients with internal devices like pacemakers or certain cerebral aneurysm clips may be unable to undergo the scan due to safety concerns.
Once screened, the patient is positioned on a movable table that slides into the MRI scanner, which is a large, tube-shaped machine. Because the scan involves no contrast injection, the process is streamlined and generally takes between 30 to 60 minutes, depending on the specific imaging sequences required. The machine produces loud knocking and humming sounds as the magnetic gradients change, so patients are provided with earplugs or headphones, often with music, to mitigate the noise.
It is necessary for the patient to remain completely still throughout the scan to prevent motion artifact, which can blur the images and make them non-diagnostic. Communication is maintained through an intercom system, and the technologist monitors the patient from a control room outside the magnetic field. Since no contrast agent is administered, there is no post-procedure recovery period related to the dye, and the patient can typically resume normal activities immediately.
Dissecting the Billing Structure
CPT code 70551 represents a global service, but for billing purposes, it is divided into two distinct components. The first is the Technical Component (TC), which covers the operational costs of performing the scan. This includes the use of the MRI equipment, facility overhead, supplies, and compensation for the technologist who acquires the images.
The second component is the Professional Component (PC), which accounts for the medical expertise required to interpret the images and generate a formal report. This fee is for the radiologist, who analyzes the scans and communicates the findings to the ordering physician. A hospital or imaging center may bill for the global service, or they may separate the charges.
When the facility (Technical Component) and the radiologist (Professional Component) bill separately, specific modifiers are appended to CPT 70551. Modifier TC is used by the facility to bill for the equipment and staff, while modifier 26 is used by the radiologist to bill solely for the interpretation service. Understanding this separation helps patients comprehend why they may receive multiple bills for a single diagnostic test.