Post #30 Use the correct CT Extremity codes to Avoiding Peer-to-Peer calls

While working as a medical director for a Radiology Benefits Manager (RBM), I was amazed how some requests were denied simply because the wrong imaging code had been requested. For example, physicians’ office representatives often requested a CT without and with contrast, when they intended to ask for only a CT without contrast. MRIs of the shoulder or knee may be needed, but the office staff asked for an MRI of the humerus or femur by mistake. Denials resulted over and over again with the very same reason for the same requesting doctor. While performing peer-to-peer calls with these providers, I often tried to teach them a few coding tips, but time was limited and physicians needed to get back to their patients. Coding for imaging studies of the musculoskeletal (MS) system falls into this coding trap. This post will provide a mini-coding course I hope will put a stop to many of your peer-to-peer calls.

CT Scanning for MS conditions

In most cases of MS imaging, MRI is the preferred imaging study because it is superior for imaging soft tissue and can define edema, loss of circulation and increased vascularity that are not demonstrated by CT scanning. However, there are times in which a CT is a better study. Obviously, patients who cannot undergo an MRI due to a pacemaker or metal in the body must settle for a CT scan. Additionally, CT renders better images of cortical bone anatomy so it is preferred for complex fractures, dislocations, and assessing delayed union or nonunion.

CT coding for the extremity


There are only 3 CPT codes for the upper extremity and 3 for the lower.

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73200, 01, and 02 may refer to any portion of the arm.

As with MRI coding, there is no way to tell from the CPT code if the imaging desired is to image the shoulder, humerus, elbow, radius/ulna, wrist or hand unless the clinical information specifies.


CPT codes for CT scans of the extremities, unlike coding for MRI, do not differentiate between joints and “other than joints.”

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73700, 01, 02 may refer to any portion of the leg

There is no way to tell from the CPT code if the imaging desired is for the CT of the hip, femur, knee, tibia/fibula, ankle or foot unless the clinical information specifies.

Additional Tips on CT Coding for the Lower Extremity

Most CT scans of the extremities are performed without contrast. Indications for CT lower extremity with contrast (CT arthrogram) are few but include suspected labral tear and suspected osteochondral fracture in patients injury who cannot have an MRI. As noted in a previous post, advanced imaging (either CT or MRI) authorization almost always requires a recent prior plain x-ray.

Radionuclide bone scans may be the preferred imaging of the extremities for suspected metastatic disease with CT or MRI scans reserved for focal lesions that appear on the bone scan.

Musculoskeletal imaging in children are selected based on unique criteria. Because the time-frame to complete an MRI may be as much as 1 hour, children often require sedation to minimize movement artifact. Physicians may not want to subject young patients to the additional expense of sedation, so when either an MRI or CT could be performed, the CT is chosen. Alternatively, CT is associated with radiation exposure that is not present with MRI scans, and this may enter into decision making.

Lesson #30: A common reason for denials and peer-to-peer phone conversations is incorrect coding for advanced imaging. If uncertain as to which test and which contrast modality would by approved, refer to the evidence-based guidelines found on radiology benefits management websites.