Radiology Coding Alert

To succeed at interventional coding, you have to be on high alert to catch every little detail. Whether the radiologist works on the patient's right or left side can make all the difference in your code choice -- and could put an extra $105 in your practice's pocket. Work your way through the sample scenario below to learn why.

Scenario: Using femoral access and common carotid placement, the radiologist images the right common carotid and right internal carotid. The radiologist documents normal anatomy and states there are no abnormalities in the common carotid, but she finds stenosis in the internal carotid.

The scenario raises several questions: Which diagnosis code should you use? How should you code catheter placement? Should you report imaging for both the common carotid and internal carotid arteries?

Depending on the documentation, the appropriate ICD-9 code for stenosis in the internal carotid alone is 433.1x (Occlusion and stenosis of precerebral arteries; carotid artery), says Jeff Fulkerson, BA, CPC, CIRCC, senior certified coder with the Department of Radiology, Emory Healthcare, in Atlanta. You must add a fifth digit to the code, basing that digit on whether the radiologist documents cerebral infarction.

You'll choose from the following options:

• 0 -- without mention of cerebral infarction

• 1 -- with cerebral infarction.

If the radiologist's dictation doesn't specifically state cerebral infarction is present, you should report 433.10, says Fulkerson. Inform the radiologist that being "as specific as possible in identifying the location of a stenosis, embolism, thrombosis, or occlusion" will aid you in selecting the proper code, such as choosing between 433.1x and 434.xx (Occlusion of cerebral arteries ...), Fulkerson adds.

To choose the proper catheter placement code, you need to identify whether the radiologist worked in the left or right carotid arteries. In the scenario above, the radiologist placed the catheter in the patient's right common carotid.

Impact: The right common carotid originates from the innominate artery which branches from the aorta. Therefore, the innominate is the first order catheterization and the right common carotid is a second order catheterization. On the other hand, the patient's left common carotid originates from the aorta in a patient with normal anatomy and is therefore a first order catheterization. (See Figure 1.)

Because of these anatomical differences, the appropriate code for a right common carotid cath placement, as described in the above scenario, is second order code 36216 (Selective catheter placement, arterial system; initial second order thoracic or brachiocephalic branch, within a vascular family), says Michele Midkiff, CPC-I, PCS, RCC, executive director of Coding Affiliates Inc., an interventional coding service in Mountain View, Calif.

On the other hand, for a left common carotid cath placement, you would report first order code 36215 (...each first order thoracic or brachiocephalic branch, within a vascular family) for a patient with a normal anatomy, Midkiff says.

Payoff: If your sharp eyes catch that you should code right carotid placement rather than left, you're in for some good news. Medicare's national nonfacility rate for 36216 ($1212) is $105 more than the rate for 36215 ($1107), using a conversion factor of 36.0846. Or if you're coding a service performed in a facility, 36216 will earn you $32 more than 36215.

Bonus tip: When coding left common carotid services,the reference to "normal anatomy" lets you know that the patient does not have what is commonly called a "bovine arch" anomaly. In that anomaly, the left common carotid becomes a second order vessel because it originates from the innominate or shares a common origin from the aorta with the innominate. (See Figure 2.)

The scenario indicates catheter placement terminated in the common carotid, but the radiologist imaged both the common and internal carotid arteries. Assuming your documentation supports it, you will be able to report imaging for both the common and internal carotid arteries.

This imaging of both vessels is possible because contrast flows upward, says Midkiff. As a result, radiologists can inject contrast at the common carotid artery and "render the interpretation of not only the common carotid bifurcation, specifying what is seen ([for example,] the common carotid bifurcation was clean and free of disease)," but also intracranial segments of the internal carotid artery, specifically findings in the cavernous, petrous, and supraclinoid segments, Midkiff explains.For the unilateral common (cervical) carotid artery angiography, you should report 75676 (Angiography, carotid, cervical, unilateral, radiological supervision and interpretation), Midkiff says. You should apply 75665 (Angiography, carotid, cerebral, unilateral, radiological supervision and interpretation) for unilateral intracranial (cerebral) carotid artery angiography, she says.

But remember to verify that the radiologist's documentation for the scenario above supports reporting the cerebral code (based on what she performed and the recorded findings) in addition to the cervical code, Fulkerson says.

Tip: The radiologist may note external carotid findings, but the radiologist must place the catheter in the external carotid(s) for you to report external carotid angiography code 75660 (Angiography, external carotid, unilateral, selective, radiological supervision and interpretation) or 75662 (Angiography, external carotid, bilateral, selective, radiological supervision and interpretation).

Smart move: Using job aids that show anatomic vasculature and the corresponding selective catheterization and angiography codes can help you keep the more complex coding scenarios straight, Midkiff says.