CT Scan of Head Without Contrast: CPT 70450

Key Takeaways

CPT Code 70450 describes a computed tomography scan of the head or brain performed without contrast material, assigned and maintained by the AMA.

Three contrast-level codes cover head CT: 70450 (without contrast), 70460 (with contrast), and 70470 (without and with contrast). Selecting the wrong one is a leading denial trigger.

Modifier 26 applies when a radiologist reads the scan at a facility; Modifier TC applies when billing only the technical component. Never append both to the same claim line.

Pabau’s claims management software helps radiology and imaging practices track modifier usage, link ICD-10 diagnosis codes, and flag incomplete documentation before claims go out.

Radiology billing departments deny more CT head claims for documentation gaps and modifier errors than for any other reason. CPT Code 70450 is one of the most frequently ordered imaging codes in emergency and outpatient settings, which makes it a common audit target for Medicare and commercial payers alike. A single missing ICD-10 code or an incorrectly appended modifier can delay reimbursement by weeks or trigger a full repayment review.

This guide covers everything radiology billers, practice managers, and coders need: the official CPT Code 70450 descriptor, medical necessity requirements, modifier rules, commonly paired ICD-10 codes, Medicare fee schedule context, CCI edit considerations, and the most common denial patterns with practical fixes. Current-year fee schedule figures change annually; always verify rates against the CMS Physician Fee Schedule lookup tool before submitting claims.

CPT Code 70450: definition and official descriptor

CPT Code 70450, as defined by the American Medical Association (AMA), reads: Computed tomography, head or brain; without contrast material. That descriptor has three key words: computed tomography, head or brain, and without contrast. All three must be true for 70450 to apply.

The code belongs to the Diagnostic Radiology section of the CPT manual, under the subsection “Diagnostic Imaging Procedures of the Head and Neck” (codes 70010-70559). It reports a cross-sectional X-ray study of the cranial vault and its contents performed using ionizing radiation, with no iodinated contrast agent administered before or during image acquisition.

Adding contrast changes the code. The full head CT family looks like this:

Billing 70460 or 70470 when only a non-contrast scan was performed is upcoding. Billing 70450 when contrast was administered is undercoding. Both create audit exposure. Document exactly what was performed and match the code to that documentation, using your EHR integration to pull the contrast administration note directly into the billing workflow.

Medical necessity and clinical indications

Medicare coverage for CPT Code 70450 is covered by CMS LCD Article A57215 (Billing and Coding: MRI and CT Scans of the Head and Neck). The local coverage determination defines which diagnoses support medical necessity. Payers routinely deny claims lacking a covered ICD-10 diagnosis code as not medically necessary, regardless of the clinical appropriateness of the scan.

Washington University’s Mallinckrodt Institute of Radiology (a Tier 2 clinical source) lists the following as established indications for non-contrast head CT:

• Acute headache or new-onset severe headache (“thunderclap” presentation)
• Head trauma with loss of consciousness, amnesia, or neurological deficit
• Suspected acute ischemic stroke or transient ischemic attack (TIA)
• Evaluation for intracranial hemorrhage or subarachnoid bleeding
• Dizziness with central nervous system etiology suspected
• Pre-operative baseline or post-operative cranial assessment
• Monitoring known intracranial lesion without active contrast requirement

Radiologists prefer non-contrast technique for acute hemorrhage because fresh blood appears hyperdense on unenhanced CT, and contrast administration can obscure that finding. For tumor surveillance or infection workup, 70460 or 70470 is more appropriate. Selecting 70450 for a patient undergoing scheduled tumor follow-up is a documentation mismatch that triggers payer scrutiny.

Always confirm that the ordering physician’s clinical indication statement in the referral or order entry matches one of the covered diagnoses in the governing LCD. Weak or vague ordering language (“rule out pathology”) is a denial risk that claims management software can flag before submission.

ICD-10 codes commonly billed with CPT Code 70450

The ICD-10-CM diagnosis code on the claim is what justifies medical necessity to the payer. For head CT without contrast, the paired diagnosis should reflect the acute symptom or condition that prompted the scan, not the suspected finding. These are the most frequently used pairings:

Use the most specific ICD-10 code available. R51.9 is appropriate when the headache cannot be further classified at the time of imaging. If a more specific headache diagnosis is documented in the record (such as G43 for migraine), use that code instead. Payers increasingly flag R51.9 on repeat imaging claims as insufficiently specific. For related ICD-10 codes for intracranial hemorrhage, see Pabau’s hemorrhage coding reference.

Modifiers for CPT Code 70450: 26, TC, and 59

Modifier usage is the most technically complex aspect of billing CPT Code 70450, and incorrect application is a top denial cause across both Medicare and commercial payers.

Modifier 26 (professional component)

Append Modifier 26 when the physician performed only the professional component: reading the images and producing a written interpretation report. This applies when the radiologist is not employed by the facility performing the scan. A hospital ER orders a head CT (70450), the facility bills for the equipment and technologist time, and the independent radiologist bills 70450-26 for the interpretation. Horizon BCBS explicitly illustrates this scenario in its modifier guidance: the film goes to the radiologist’s office by courier, and the radiologist bills 70450-26 only.

Modifier TC (technical component)

Modifier TC covers the equipment, technologist, room, and supplies. The facility bills 70450-TC. This is the mirror image of Modifier 26. When a single entity owns both the scanner and employs the reading radiologist, they bill the global code (70450 without any modifier), which captures both components. Appending both Modifier 26 and TC to the same claim line is an error; that combination effectively double-bills the global service.

Modifier 59 (distinct procedural service)

Modifier 59 signals that 70450 is a separate, distinct service from another procedure billed on the same date. Use it only when there is a genuine clinical basis for performing two imaging services that would otherwise be bundled under CCI edits. Never append Modifier 59 routinely to bypass bundling rules; that is improper billing and creates false claims risk. Verify the specific edit pair in the current HIPAA-compliant documentation practices framework, and consult the NCCI tables before appending.

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CPT 70450 and 70496: when they cannot be billed together

CPT Code 70496 describes CT angiography of the head (CTA Head), a different study that evaluates intracranial blood vessels using timed contrast injection. The AAPC coding community, confirmed in forum threads reviewed in preparation for this article, holds that when a CT brain without contrast (70450) and a CTA brain (70496) are performed in the same session for the same clinical indication, only 70496 should be reported. The reasoning: the CTA study includes the diagnostic information of the plain non-contrast acquisition.

This does not mean 70450 and 70496 are always mutually exclusive. If the non-contrast scan is performed for a distinct clinical reason on the same day (for example, trauma evaluation followed by a separate vascular workup), Modifier 59 may be appropriate. Verify this against current NCCI edits before billing; edit pairs change with each quarterly update. Note that this claim is assessed as “likely” confidence based on community sources; confirm against current CCI edit tables before asserting it as a definitive rule for your payer mix. See additional procedure billing references for related code combination guidance.

Medicare reimbursement for CPT Code 70450

Medicare pays for CPT Code 70450 under the Physician Fee Schedule (PFS) for professional component claims and under the Outpatient Prospective Payment System (OPPS) for hospital outpatient departments. These two payment systems produce different reimbursement amounts for the same code, which is why a hospital ER claim and a freestanding imaging center claim for identical scans may generate different Medicare payments.

The FastRVU 2026 RVU lookup tool shows the relative value unit breakdown for 70450, with work RVUs, practice expense RVUs, and malpractice RVUs contributing to the total. The Medicare conversion factor multiplies the total RVU sum to produce the allowed amount. Because the conversion factor and geographic practice cost indices (GPCIs) change annually, always look up current-year rates directly from the CMS fee schedule rather than relying on published tables that may be a year out of date.

Key payment distinctions for 70450:

• Global billing (no modifier): Higher payment capturing both professional and technical RVUs. Only for practices owning equipment and employing their own radiologists.
• Professional component only (Modifier 26): Receives the professional component RVUs only. Typically used by independent radiology groups reading for facilities.
• Technical component only (Modifier TC): Receives the technical component RVUs. Used by facilities billing separately from the radiologist.
• OPPS vs. PFS: Hospital outpatient departments are paid under OPPS Ambulatory Payment Classifications (APCs), which may differ from PFS amounts. Independent imaging centers bill PFS.

Commercial payer rates for CPT Code 70450 vary widely. Some payers pay a percentage of Medicare; others use contracted fee schedules negotiated at the practice level. Prior authorization requirements also differ by payer and by patient plan. Many managed Medicaid plans require authorization for advanced imaging even in urgent settings. Confirm authorization requirements before scanning whenever possible, and document any emergency exceptions per your payer’s policy.

Documentation requirements for CPT Code 70450

Medical necessity for CPT Code 70450 lives or dies in the documentation. Payers auditing radiology claims look for four elements:

1. A signed, dated physician order specifying CT of the head or brain without contrast and documenting the clinical indication. Auditors commonly flag verbal orders transcribed without timely authentication.
2. A radiology report containing the study description (technique, without contrast), clinical history, findings, and impression. Reports missing the technique statement (“performed without contrast material”) leave the code selection unverifiable.
3. A matched ICD-10 diagnosis code that is covered under the applicable LCD. Documentation in the order or clinical notes must support the ICD-10 code on the claim, not just the radiology report impression.
4. Evidence of medical necessity in the ordering clinician’s notes. For Medicare, this means the clinical note must show a problem that meets LCD coverage criteria. A three-word indication (“rule out pathology”) does not meet that standard.

Practices using digital intake forms can pre-populate referring physician order templates with required fields, reducing the rate of incomplete orders that arrive in the billing department. Standardized order entry reduces the documentation gaps that cause avoidable denials. For broader guidance on documentation best practices, see Pabau’s resource on medical documentation workflows.

Common denial reasons and how to avoid them

CPT Code 70450 generates a predictable set of denial patterns. Most are preventable with front-end workflow controls rather than back-end appeals.

Denial: not medically necessary

The ICD-10 code on the claim does not appear on the payer’s covered diagnosis list for CT head. Fix: build a crosswalk table mapping the 10-15 most common ordering indications at your practice to their covered ICD-10 codes. Use a practice management software rules engine to validate the pairing before claim submission.

Denial: missing or invalid modifier

The claim was submitted global when the radiologist is independent, or with Modifier 26 when the practice owns the equipment and employs the radiologist. Fix: set up payer-specific billing profiles that auto-assign the correct modifier based on your practice’s service agreement with each facility. Review modifier assignment in every remittance cycle.

Denial: authorization required

The payer required prior authorization and none was obtained. Fix: maintain an up-to-date authorization matrix by payer and plan type. For Medicare Advantage plans in particular, authorization requirements can differ substantially from traditional Medicare. Use automated billing workflows to trigger authorization requests at order entry, not at the time of scanning.

Denial: duplicate claim

Two claims for 70450 appear on the same date for the same patient, typically because both the facility and the radiologist billed globally. Fix: coordinate billing responsibilities between the facility and independent radiology group in writing. Confirm which entity owns the global versus split billing responsibility before the contract goes live. Review your HIPAA compliance checklist to ensure billing coordination processes are documented and auditable.

CCI edits and bundling considerations

The Centers for Medicare and Medicaid Services (CMS) National Correct Coding Initiative (NCCI) edits table identifies code pairs that cannot be billed together without a modifier indicating a distinct service. CMS LCD Article A57215 explicitly states that CPT codes in radiology may be subject to CCI edits; coders must verify current edit pairs before billing any combination that includes 70450.

The most relevant bundling scenario for CPT Code 70450 is the 70450/70496 combination described earlier. An additional consideration: 70470 (without and with contrast) should never appear on the same claim as either 70450 or 70460 for the same anatomical site on the same date. Billing 70470 already captures the without-contrast phase; adding 70450 separately double-bills that phase.

For imaging practices that perform high volumes of head CT, a quarterly CCI edit table review is a worthwhile compliance activity. CMS updates edit pairs on a quarterly schedule, and a combination that was billable in Q1 may be bundled from Q2 onward. Using CPT billing reference guides alongside live CCI tables keeps your compliance position current. Confirm all edits against the official NCCI tables published by CMS before applying them to live claims.

Conclusion

CPT Code 70450 is a high-volume, high-scrutiny code. The gap between a clean claim and a denial usually comes down to three things: a matched ICD-10 code that satisfies LCD medical necessity criteria, the correct modifier reflecting who actually performed and read the scan, and a radiology report that documents the non-contrast technique explicitly.

Pabau’s claims management software gives radiology and imaging practices the workflow controls to catch these issues before submission, linking diagnosis codes to procedures, flagging modifier conflicts, and surfacing incomplete documentation at the order entry stage rather than after a denial. To see how it fits your billing workflow, book a demo.

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