Most Audited Radiology CPT Codes by Medicare

Why Medicare Targets Certain Radiology CPT Codes

Medicare audit activity is driven by data analytics. Codes are flagged when billing patterns deviate from expected norms.

Common audit triggers include:

• High utilization compared to peers

• Frequent use of advanced imaging

• Inconsistent documentation across providers

• Improper modifier or component billing

Radiology is particularly vulnerable because imaging services are high volume and high cost.

CT Scan CPT Codes Under Medicare Scrutiny

CT imaging represents one of the largest audit focus areas due to utilization growth and reimbursement levels.

Frequently audited CT CPT codes include:

• 70450 CT head without contrast

• 70460 CT head with contrast

• 70470 CT head with and without contrast

• 71260 CT chest with contrast

• 74177 CT abdomen and pelvis with contrast

Common audit issues:

• Incorrect contrast coding

• Missing medical necessity documentation

• Duplicate billing of technical and professional components

MRI CPT Codes Most Commonly Audited

MRI studies are expensive and subject to strict medical necessity standards.

High audit focus MRI CPT codes include:

• 70551 MRI brain without contrast

• 70553 MRI brain with and without contrast

• 72148 MRI lumbar spine without contrast

• 72156 MRI cervical spine with and without contrast

Audit findings often cite:

• Weak clinical indications

• Lack of prior authorization documentation

• Improper frequency of repeat studies

Nuclear Medicine and PET Scan CPT Codes

Nuclear imaging is heavily regulated due to cost and radiation exposure.

Commonly audited codes include:

• 78452 Myocardial perfusion imaging

• 78815 PET scan whole body

• 78816 PET scan with attenuation correction

Errors often involve:

• Incorrect patient eligibility

• Missing oncology related diagnoses

• Improper supervision requirements

Ultrasound CPT Codes That Trigger Reviews

Ultrasound is lower cost than CT or MRI but still subject to audit when utilization is excessive.

Medicare frequently reviews:

• 76700 Abdominal ultrasound complete

• 76856 Pelvic ultrasound

• 93306 Echocardiography complete

Audit concerns typically relate to:

• Incomplete reports

• Duplicate studies

• Lack of clinical correlation

Mammography CPT Codes and Compliance Audits

Breast imaging is governed by specific Medicare quality and reporting standards.

Audited CPT codes include:

• 77067 Screening mammography bilateral

• 77066 Diagnostic mammography bilateral

Audits often assess:

• Screening versus diagnostic classification

• Proper use of add on codes

• Compliance with reporting requirements

Modifier Related Audit Risks in Radiology

At this stage, many groups begin reassessing internal workflows versus outsourced Radiology Billing services, especially when modifier related denials and post payment reviews increase.

Modifier misuse is a consistent audit finding.

High risk areas include:

• Incorrect use of modifier 26 or TC

• Global billing when services were split

• Duplicate billing between facility and physician

Modifier errors frequently result in overpayment determinations.

Documentation Deficiencies That Lead to Recoupments

Across all audited CPT codes, documentation is the deciding factor.

Common deficiencies include:

• Vague clinical indications

• Missing physician signatures

• Inconsistent reports

• Lack of medical necessity justification

Medicare expects documentation to clearly support why the imaging study was required.

How Radiology Practices Can Reduce Medicare Audit Risk

Audit prevention strategies include:

• Regular CPT and modifier audits

• Standardized documentation templates

• Education on Medicare medical necessity rules

• Monitoring utilization patterns by modality

Proactive compliance is far less costly than post payment recovery.

When to Take Audit Risk Seriously

Practices should act when:

• Medicare requests records frequently

• Recoupment letters increase

• Denials cite medical necessity

• Peer comparison data shows outliers

These are early warning signs of deeper issues.

Final Thoughts

Medicare most frequently audits high cost and high utilization radiology CPT codes including CT, MRI, nuclear medicine, ultrasound, and mammography. Audit focus areas include medical necessity documentation, contrast coding accuracy, modifier use, and utilization patterns. Radiology practices that monitor CPT trends, benchmark utilization, strengthen documentation, and proactively review billing behavior are better positioned to avoid recoupments, expanded audits, and long term compliance scrutiny.

Medicare radiology audits are driven by patterns, not isolated errors. Practices that address risk at the CPT and documentation level protect revenue before enforcement actions occur.