Current Procedural Terminology (CPT) codes are standardized identifiers developed and maintained by the American Medical Association (AMA) to describe medical services and procedures performed by healthcare providers. These codes are the uniform language used by doctors, hospitals, and insurers for billing and reimbursement. This framework ensures consistency in medical documentation and claims processing. This article focuses on CPT Code 70551, which designates a diagnostic scan used to visualize the structures of the central nervous system.
The Specifics of CPT Code 70551
CPT Code 70551 officially identifies the service as “Magnetic resonance imaging, brain, without contrast material(s).” This procedure is a Magnetic Resonance Imaging (MRI) scan of the brain, including the brainstem, that does not involve the intravenous administration of a specialized agent. The core distinction is the phrase “without contrast,” indicating that no contrast dye was used during the imaging session.
A contrast agent is typically a gadolinium-based substance injected into a vein to enhance the visibility of tissues, blood vessels, or abnormalities. The absence of this substance affects both the procedure and the resulting images.
The 70551 code covers both the technical component—the use of the MRI machine and the staff operating it—and the professional component, which is the interpretation of the resulting images by a qualified radiologist.
Performing the scan without an enhancing agent simplifies the logistics, removing the step of placing an intravenous line and administering the dye. For the patient, this also eliminates the potential for side effects associated with contrast material, such as allergic reactions or issues related to kidney function.
Clinical Applications for a Non-Contrast MRI
A non-contrast MRI (CPT 70551) provides excellent detail of the brain’s soft tissues, making it suitable for a wide range of initial evaluations. For example, a non-contrast study is often sufficient for assessing acute stroke, particularly in the initial hours, where it can quickly identify signs of hemorrhage or early ischemic changes.
The non-contrast technique is also frequently used to evaluate acute trauma, as it is highly sensitive to blood products and can detect signs of bleeding within the brain. Furthermore, certain developmental anomalies and chronic conditions like hydrocephalus are well-visualized without contrast enhancement, as the abnormal accumulation of cerebrospinal fluid is clearly seen on standard MRI sequences.
The absence of a contrast agent may also be a medical necessity, such as when a patient has a known severe allergy to gadolinium or has poor kidney function, making it unsafe to administer the dye. The physician relies on the intrinsic tissue contrast provided by the MRI machine to gather diagnostic information, allowing for the detection of structural issues, white matter changes, and the overall anatomy of the brain and brainstem.
Understanding the Difference Between Related CPT Codes
The distinction between CPT 70551 and its related codes lies entirely in the use of the contrast agent, and this difference directly impacts the diagnostic yield and billing. CPT Code 70552 describes the same procedure—Magnetic Resonance Imaging of the brain—but it is performed with contrast material(s). This is typically ordered when there is a strong suspicion of conditions that cause a breakdown in the blood-brain barrier, such as an active brain tumor, abscess, or certain types of active infection.
The contrast dye highlights these areas by leaking into the abnormal tissue, which causes them to “light up” brightly on the resulting images, offering a clear boundary for assessment. When a physician needs both the baseline tissue information and the enhanced detail provided by the dye, CPT Code 70553 is used. This code represents an MRI of the brain that is performed without contrast material, followed by with contrast material in the same session.
The 70553 procedure is considered the most comprehensive, as it provides a direct comparison between the native tissue appearance and its enhanced appearance after dye administration. It is commonly utilized when evaluating for new-onset seizures, suspected tumors, or monitoring the activity of multiple sclerosis lesions. CPT 70553 is billed as a single, combined service, which is distinct from billing 70551 and 70552 separately, ensuring accurate cost reflection for the two-part procedure.