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What is CPT code 73721 — its description, types, reimbursement, modifiers, and service time?
What is CPT code 73721 and its Description?
CPT 73721 refers to magnetic resonance imaging (MRI) of any lower extremity joint (hip, knee, ankle, or foot) performed without the use of contrast material. This non-invasive imaging technique produces detailed pictures of the joint’s internal structures, like bones, cartilage, and soft tissues to diagnose conditions such as ligament tears, bone fractures, arthritis, degenerative joint diseases, and other abnormalities.
What are the Types of MRI Codes Related to CPT 73721?
CPT 73721: MRI of lower extremity joint without contrast
CPT 73722: MRI of lower extremity joint with contrast
CPT 73723: MRI of lower extremity joint, both without and with contrast
Thus, 73721 specifically refers to non-contrast MRI of lower extremity joints.
How is CPT 73721 Reimbursed?
Reimbursement varies by payer and region. Medicare and private insurers generally cover CPT 73721 when medically justified with proper documentation. Some insurers may require prior authorization. Payment rates depend on geographic location and payer policies.
Which Modifiers are Commonly Used with CPT 73721?
Modifier 26: Professional component (interpretation and report by radiologist)
Modifier TC: Technical component (use of MRI equipment and technician services)
Modifier 50: Bilateral procedure (both left and right joints scanned)
Modifiers LT/RT: Specify left or right side for unilateral imaging
Modifier 52: Reduced services (partial or incomplete procedure)
Modifier 53: Discontinued procedure (stopped for patient safety after anesthesia)
Modifier 59: Distinct procedural service (separate imaging on the same day)
Modifier 76: Repeat procedure by same provider on same day
Modifier 77: Repeat procedure by different provider on same day
What is the Typical Service Time for CPT 73721?
The MRI procedure time for CPT 73721 usually ranges from about 30 to 60 minutes, depending on the complexity of the joint, protocols used, and facility workflow. Exact times may vary.
Summary Table:
| Aspect | Details |
|---|---|
| Procedure | MRI of any lower extremity joint without contrast |
| Common Joints | Knee, hip, ankle, foot |
| Types | 73721 – without contrast; 73722 – with contrast; 73723 – both |
| Purpose | Diagnose ligament tears, fractures, arthritis, joint abnormalities |
| Reimbursement | Covered by Medicare/private insurers; requires proper documentation; prior auth may apply |
| Common Modifiers | 26, TC, 50, LT, RT, 52, 76, 77 |
| Approximate Service Time | 30-60 minutes |
How to choose modifiers for 73721 in mixed MRI sessions
When choosing modifiers for CPT code 73721 in mixed MRI sessions, the following guidelines are key:
Modifier 26 (Professional Component): Use when billing only the interpretation and report by the radiologist, separate from the facility or technical service.
Modifier TC (Technical Component): Use when billing only for the technical aspect, such as use of MRI equipment and technician services.
Modifiers LT (Left) and RT (Right): Use to specify which side of the lower extremity was imaged when the MRI is unilateral.
Modifier 50 (Bilateral Procedure): Used if the MRI is performed on both left and right lower extremity joints in the same session. However, note that 73721 is not inherently bilateral, and Medicare does not reimburse full payment for each side when 50 is used.
Modifier 59 (Distinct Procedural Service): Used when multiple imaging services are performed on the same day and need to be distinguished as separate.
Modifiers 76 and 77 (Repeat Procedures by Same or Different Providers): Use when the MRI is repeated on the same day due to clinical reasons or technical issues.
Modifier 52 (Reduced Services): When the MRI was partially reduced or incomplete but still performed.
Modifier 53 (Discontinued Procedure): When the procedure is stopped early for patient safety reasons after anesthesia.
In mixed MRI sessions involving multiple procedures or different service components, append modifiers 26 and/or TC to properly indicate professional and technical billing. Use LT/RT or 50 to specify laterality. Use 59 to indicate distinct services, and use 76/77 for repeats as needed. Proper modifier use clarifies the service context and helps prevent denials or underpayments.
Summary Table:
| Modifier | Use Case | Notes |
|---|---|---|
| 26 | Professional component only | Radiologist’s interpretation & report |
| TC | Technical component only | MRI equipment, technician services |
| LT | Left side imaging only | Specify if only left joint scanned |
| RT | Right side imaging only | Specify if only right joint scanned |
| 50 | Bilateral procedure | Both left and right lower extremity joints scanned |
| 59 | Distinct procedural service | Separate imaging services same day |
| 76 | Repeat procedure by same provider same day | Repeat MRI for clinical/technical reasons |
| 77 | Repeat procedure by a different provider same day | Repeat MRI by different radiologist |
| 52 | Reduced services | Partial/incomplete procedure |
| 53 | Discontinued procedure | Procedure terminated early for patient safety |
What is the difference between CPT code 73721 and 73718?
The main difference between CPT code 73721 and CPT code 73718 lies in the anatomical focus of the MRI scans:
CPT 73721: This code is used for magnetic resonance imaging (MRI) of any joint of the lower extremity (such as hip, knee, ankle, or foot) without contrast material. It specifically addresses joint imaging to diagnose ligament tears, bone fractures, arthritis, and other joint abnormalities.
CPT 73718: This code is for MRI of the lower extremity, other than the joint, also without contrast. It includes imaging of the thigh, lower leg, or foot bones (long bones) and soft tissues surrounding those bones, excluding the joints. It is used to evaluate muscle, tendon, bone, and soft tissue problems that are not directly involving the joint itself.
Both codes are commonly used for diagnostic imaging in the lower extremities but differ in whether the scan targets the joint structures (73721) or the non-joint anatomical areas like long bones and soft tissues (73718).
What is the CPT code for knee imaging?
Knee imaging CPT codes vary by the type of imaging, such as X-ray or MRI, and the number of views or contrast used. For example, 73560-73564 are used for knee X-rays, with different codes for 1-2, 3, or 4+ views, while 73721 is for an MRI of the knee joint.
X-Ray Knee Imaging Codes
These codes depend on the number of X-ray views taken:
- 73560: Knee, 1 or 2 views
- 73562: Knee, 3 views
- 73564: Knee, complete, 4 or more views
- 73565: Bilateral standing knees
MRI Knee Imaging Codes
- 73721: This code is for an MRI of the lower extremity joints, including the knee.
- 73723: This code is for an MRI with both without contrast and then with contrast.
Other Imaging Types
- 73580: This code is for radiological supervision and interpretation of a knee arthrography.
Important Considerations
- Type of Study: Always identify whether the imaging is an X-ray, MRI, or arthrogram.
- View Count (X-ray): For X-rays, the specific number of views determines the correct code.
- Contrast (MRI): For MRI, you need to specify if contrast material was used.
- Bilateral vs. Unilateral: Some codes, like 73565, specify “bilateral” for both knees.
- Professional vs. Technical Component: CPT codes can represent the technical component (the imaging itself) or the professional component (the interpretation by the radiologist).
Is CPT code 73721 bilateral?
No, CPT code 73721 is not a bilateral code; it is a unilateral code for a single lower extremity joint (hip, knee, or ankle) MRI without contrast, and requires separate coding for each joint and each side. To report bilateral imaging or multiple joints, you should report the code once for each joint and consider using the modifier 59 or LT/RT modifiers depending on the payer’s requirements.
How to bill CPT 73721 bilaterally?
Payer-specific instructions
Common billing methods for bilateral radiology procedures include:
- Use of anatomical modifiers (LT and RT): The code is listed on two separate lines on the claim form, with one line appended with the
-LTmodifier (left side) and the other with the-RTmodifier (right side).- Example:
73721-LTon one line and73721-RTon another.
- Example:
- Use of modifier 50: Some payers may accept the bilateral modifier
-50. For these payers, the code is typically billed on a single claim line with one unit of service and the-50modifier appended. - Use of a “2” in the units field: Some payers have a policy that requires the code to be listed as a single entry with “2” in the units field to indicate both sides were treated.
General Medicare guidance:
-50 is generally not recommended. The standard practice is to use the anatomical modifiers -RT and -LT on separate claim lines. 