Imaging · Knee

MRI of a lower extremity joint (hip, knee, or ankle) performed without contrast material.

Verified May 8, 2026 · 5 sources ↓

Medicare: $204.41
Total RVUs: 6.12
Global, days
Region: Knee

Drawn from CMSA2zbillingsMtnmedical

Documentation requirements

What must appear in the operative or office note to support the claim.

Source · Editorial brief grounded in 5 cited references ↓

Clinical indication documenting medical necessity — diagnosis or symptom driving the order (e.g., meniscal tear, ligament injury, joint pain unresponsive to conservative treatment)
Explicit confirmation that no contrast was administered; note must distinguish the study as without-contrast to support 73721 over 73722 or 73723
Specific joint imaged (hip, knee, or ankle) with laterality when required by payer
Ordering provider's written or electronic order referencing the clinical indication
Radiologist's interpretation report addressing the structures evaluated and findings relevant to the clinical question
Prior authorization number if required — many commercial payers require pre-auth for outpatient MRI

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

26 Professional component 59 Distinct service 76 Repeat, same physician 77 Repeat, another physician LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 5 cited references ↓

CPT 73721 covers a non-contrast MRI of any lower extremity joint — hip, knee, or ankle. The study captures bone, cartilage, ligament, tendon, and soft-tissue structures without administration of contrast dye. It sits in a three-code family: 73721 (without contrast), 73722 (with contrast), and 73723 (without and with contrast in the same session). Billing the wrong code in that family — most often 73721 when contrast was actually given — triggers downcoding or outright denial.

The global period is XXX, meaning no global surgical package applies; each study is billed as a standalone service. When a radiologist reads the scan at a facility that owns the equipment, billing splits into modifier 26 (professional component) and TC (technical component). Some payers — particularly Medicare Advantage and commercial plans — require laterality modifiers LT or RT for knee and ankle studies. Confirm payer-specific requirements before submission.

RVU & reimbursement

Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	1.32
Practice expense RVU	4.71
Malpractice RVU	0.09
Total RVU	6.12
Medicare national rate	$204.41
Global period	days

Payment by site of service

Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.

Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026

Setting	Medicare rate (national)
Office (PFS non-facility) Procedure performed in physician's office	$204.41
HOPD (APC 5523) Hospital outpatient department	$243.77

Common denial reasons

The recurring reasons claims for CPT 73721 get rejected.

Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓

Wrong contrast code selected — 73721 billed when contrast was administered; payer downcodes or denies
Missing or insufficient medical necessity documentation; payer cannot establish that conservative treatment was attempted or that the clinical indication meets coverage criteria
Laterality modifier absent when payer policy requires LT or RT for knee or ankle studies
Prior authorization not obtained or not linked to the claim on submission
Component billing error — facility and professional component both billed globally when the split-billing arrangement requires modifier 26 and TC

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01When should I use 73721 versus 73722 versus 73723?

73721 is without contrast only. 73722 is with contrast only. 73723 is without and with contrast in the same session. If contrast was injected at any point during the study, 73721 is wrong. Verify the imaging order and the radiology report before selecting the code.

02Do I need laterality modifiers LT or RT for 73721?

Not universally — Medicare fee-for-service does not require laterality for 73721, but many commercial payers and Medicare Advantage plans do. Check each payer's claim editing requirements. Missing a required laterality modifier is a common, easily preventable rejection.

03How does component billing work for 73721?

When a radiologist interprets at a hospital or independent imaging center that owns the MRI equipment, the physician bills 73721-26 for interpretation and the facility bills 73721-TC. A private practice that owns its own equipment and employs the radiologist bills the global code with no modifier.

04Is prior authorization required for 73721?

It depends on the payer. Most commercial plans and many Medicare Advantage plans require prior auth for outpatient MRI. Medicare traditional fee-for-service does not require prior auth but does require documented medical necessity. Confirm before scheduling.

05Can 73721 be billed the same day as a knee arthroscopy or injection?

Yes, but expect scrutiny. If an orthopedic surgeon orders the MRI on the same day as an E/M or procedure, medical necessity for same-day imaging must be clearly documented. Some payers bundle diagnostic imaging obtained for pre-procedure planning into the procedure itself — check NCCI edits and payer-specific policies before submitting.

06What is the global period for 73721?

XXX — no global surgical period applies. Each study is billed independently with no pre- or post-service period attached.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira AI Scribe

Mira's AI scribe captures the specific joint imaged, laterality, confirmation that no contrast was used, and the clinical indication driving the order — all from dictation. That prevents the most common denial trigger: a claim where the contrast status or joint site is ambiguous and the payer defaults to a lower-paying code or rejects outright.

See how Mira captures CPT 73721 documentation