Summary & Overview
CPT 73721: MRI of Lower Extremity Joint, without Contrast
CPT 73721 denotes a non-contrast magnetic resonance imaging study of any joint in the lower extremity. As a widely used diagnostic imaging service in orthopedics and sports medicine, this code is central to evaluating knee, ankle, hip, and related joint complaints, informing surgical planning and conservative management decisions. Nationally, non-contrast joint MRI is a common, high-value diagnostic tool given its soft-tissue resolution and lack of ionizing radiation.
Major payers addressed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication provides a concise overview of coverage considerations and billing practices tied to 73721, highlights common clinical indications, and clarifies the typical outpatient hospital setting where these studies occur. Readers will find benchmarks for utilization context, comparisons to contrast-enhanced alternatives, and notes on documentation and coding relationships relevant to billing workflows. When specific input elements were unavailable, the text notes "Data not available in the input." The aim is to give coding, billing, and compliance professionals a clear, actionable summary of what 73721 represents, where it is commonly performed, and how it fits into diagnostic imaging for lower-extremity joint conditions.
CPT Code Overview
CPT 73721 describes magnetic resonance (proton) imaging of any lower extremity joint performed without intravenous contrast material. This procedure falls under Diagnostic Radiology (Diagnostic Imaging) Procedures of the Lower Extremities and is typically performed in an Outpatient Hospital (POS 22) setting. The code captures non-contrast MRI studies focused on joints of the lower limb to evaluate structural, degenerative, and traumatic conditions.
Clinical & Coding Specifications
Clinical Context
A middle-aged outpatient presents to an outpatient hospital radiology department with focal knee pain and mechanical symptoms after a twisting injury. The orthopedic clinic orders diagnostic imaging to evaluate for internal derangement. The patient checks in at the outpatient hospital (POS 22) and undergoes a non-contrast magnetic resonance imaging study of the affected lower extremity joint to assess ligaments, menisci, articular cartilage, and periarticular soft tissues. Imaging is performed by the hospital radiology technologist, interpreted by a radiologist, and results are communicated to the referring orthopedic surgeon for management planning.
Coding Specifications
Modifier 26 - Professional Component
- Use when reporting the radiologist’s interpretation and report separate from the technical service.
Modifier TC - Technical Component
- Use when reporting the facility/technical portion only (equipment, technician, and technical staff services).
Modifier 59 - Distinct Procedural Service
- Use when a separate, distinct imaging procedure or service is performed that is not usually reported together, to indicate a service unrelated to other services performed on the same day.
Associated provider taxonomies
| Taxonomy Code | Taxonomy Name |
|---|---|
| Data not available in the input. | Data not available in the input. |
Related Diagnoses
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M25.561- Pain in right knee- Relevant as an indication for diagnostic MRI of the knee to evaluate internal derangement or other causes of localized pain.
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M25.562- Pain in left knee- Relevant as an indication for diagnostic MRI of the knee to evaluate internal derangement or other causes of localized pain.
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M17.11- Unilateral primary osteoarthritis, right knee- Relevant as a chronic degenerative condition that may be evaluated with MRI when clinical correlation or surgical planning requires detailed assessment of cartilage and menisci.
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M17.12- Unilateral primary osteoarthritis, left knee- Relevant as a chronic degenerative condition that may be evaluated with MRI when clinical correlation or surgical planning requires detailed assessment of cartilage and menisci.
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S83.511A- Sprain of anterior cruciate ligament of right knee, initial encounter- Relevant as an acute ligamentous injury commonly evaluated by MRI to assess the anterior cruciate ligament and associated internal derangements.
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S83.512A- Sprain of anterior cruciate ligament of left knee, initial encounter- Relevant as an acute ligamentous injury commonly evaluated by MRI to assess the anterior cruciate ligament and associated internal derangements.
Related CPT Codes
73722 - Magnetic resonance imaging, any joint of lower extremity; with contrast material
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73722describes the same anatomic study performed with intravenous contrast. It is an alternative when contrast-enhanced evaluation is clinically indicated. -
In clinical workflow,
73721(without contrast) is commonly performed first;73722may be used when additional contrast-enhanced sequences are required. -
These codes are alternatives for the same modality and anatomic region; they are not reported together for the same study.
National Reimbursement Benchmarks
Medicare mean allowed rate is substantially lower than the BUCA commercial mean, with Medicare at $141.91 versus BUCA at $257.09 nationally for CPT 73721. This reflects a roughly $115.18 gap between Medicare and the average commercial benchmark represented by BUCA.
Rate dispersion (P75 minus P25) varies across payers. Cigna shows one of the widest interquartile spreads (330.00 - 147.00 = $183.00), followed by Blue Cross Blue Shield (328.00 - 182.00 = $146.00). Aetna and UnitedHealth Group have moderate dispersion (Aetna: $141.83; UHC: $161.33), while BUCA is tighter (304.49 - 180.00 = $124.49). Medicare has a smaller absolute spread (197.50 - 66.00 = $131.50) compared with many commercial payers.
The table and chart below present the full payer-level breakdown of mean rates and key percentiles for CPT 73721.
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