What does CPT code 70551 represent for an MRI of the brain without contrast?

CPT Code 70551: MRI Brain Without Contrast

CPT code 70551 represents an MRI of the brain performed without intravenous contrast material.

Code Definition and Clinical Use

CPT 70551 is the standard billing code for a non-contrast brain MRI examination. This code is distinct from:

• CPT 70552: MRI brain with contrast
• CPT 70553: MRI brain without and with contrast
• CPT 70554-70555: Functional MRI (fMRI) with specific activation protocols 1

When This Code is Appropriate

Primary Clinical Scenarios

MRI brain without contrast (70551) is usually appropriate for:

• Acute stroke evaluation when MRI is chosen over CT, as it provides superior sensitivity for detecting acute infarction through diffusion-weighted imaging (DWI) sequences 2
• Initial screening for suspected brain pathology when contrast is contraindicated (renal impairment, contrast allergy) 2, 3
• Follow-up of known hemorrhage to assess evolution and complications 2
• Posterior reversible encephalopathy syndrome (PRES) evaluation in hypertensive emergency 3

When Contrast Should Be Added (70553 Instead)

The evidence strongly indicates that MRI without and with contrast (CPT 70553) is preferred over 70551 alone for:

• Suspected brain tumors - contrast is critical for delineating tumor extent and characterizing enhancement patterns 4
• Optic neuritis and visual pathway disorders 5
• Suspected intracranial infection (meningitis, encephalitis, abscess) 3
• Evaluation of cranial nerve palsies affecting the cisternal or skull base segments 5
• Proven parenchymal hemorrhage when searching for underlying vascular malformation or mass 2
• Altered mental status with suspected mass, infection, or inflammatory pathology 3

Important Clinical Caveats

Common Pitfalls

1. Underutilization in altered mental status: While CT is first-line for acute altered mental status, MRI without contrast can detect occult pathology missed on CT, including small ischemic infarcts (which account for 70% of missed stroke diagnoses presenting as altered mental status) 3

2. Inadequate for tumor characterization: If a mass lesion is suspected based on clinical presentation or prior imaging, ordering 70551 alone will likely require a repeat study with contrast, exposing the patient to additional time, cost, and inconvenience 4

3. Limited value in delirium without risk factors: In elderly patients with new-onset delirium, brain imaging has very low yield unless specific risk factors are present: focal neurologic deficit, recent falls/head injury, anticoagulation, elevated intracranial pressure signs, or significant consciousness deterioration 3

When 70551 May Be Sufficient

Non-contrast MRI provides adequate diagnostic information for:

• Detecting acute ischemia (DWI/ADC sequences)
• Identifying hemorrhage (especially with susceptibility-weighted imaging)
• Evaluating white matter disease
• Assessing for hydrocephalus or mass effect
• Screening when contrast is absolutely contraindicated 2, 3, 6

Practical Algorithm

Choose CPT 70551 (without contrast) when:

• Acute stroke protocol is needed
• Screening for structural abnormality with contrast contraindication
• Following known hemorrhage evolution
• Evaluating non-enhancing pathology (demyelination, edema patterns)

Upgrade to CPT 70553 (without and with contrast) when:

• Any suspicion for neoplasm (primary or metastatic)
• Infectious/inflammatory process suspected
• Vascular malformation evaluation
• Cranial nerve or visual pathway pathology
• Characterizing any abnormality found on prior non-contrast imaging

The additional cost of contrast administration is justified by avoiding repeat examinations and providing definitive diagnostic information in a single study 5, 2, 3, 5, 4.