CT and CTA on the Same Day – OK to Code? The Answer is More Complex Than You May Think.

“Can we code and bill for both a CT and CTA on the same day?”

This is one of the most frequently asked questions when we talk about diagnostic imaging. The answer? Technically, yes, and yet the answer is not that straightforward. With many situations there’s generally a ‘but’ with these types of answers and here the documentation needs to be crystal clear in order to submit codes for both exams.

Before we get to those documentation requirements, a quick review.

CT and CTA – What’s the Difference?

Computed tomography (CT) scans take cross-sectional images of soft tissues or skeletal anatomy. Computed tomography angiography (CTA) takes the CT scan a step further by creating cross-sectional images of soft tissues, skeletal anatomy, and vascular structures. After the scan is complete, computer post-processing is used to create 3D images.

This 3D post-processing is the key distinction between a standard CT and a CTA.

The imaging of the vessels alone is not necessarily considered a CTA for coding purposes. To report a CTA code, 3D post-processing must be done to evaluate the vessels – if there is no 3D reformatting performed to evaluate the vessels, then the exam should be coded as a CT and not a CTA. If the details in the documentation are unclear as to whether the exam should be coded as a CTA vs. a CT, it’s always best to request clarification. Even though a physician may identify a procedure as a CTA, that’s not always the case from a coding perspective.

Code selections should be made based on the services provided and detailed in the documentation.

CT and CTA Performed on the Same Day

For situations where a CT and a CTA are performed on the same day, the NCCI Policy Manual for Medicare Services says the following in Chapter IX, Section D:

“Computed tomography (CT) and computed tomographic angiography (CTA) procedures for the same anatomic location may be reported together in limited circumstances. If a single technical study is performed which is used to generate images for separate CT and CTA reports, only one procedure, either the CT or CTA, for the anatomic region may be reported. Both a CT and CTA may be reported for the same anatomic region if they are performed at separate patient encounters or if two separate and distinct technical studies, one for the CT and one for the CTA, are performed at the same patient encounter. The medical necessity for the latter situation is uncommon.”

But there are some important things to consider before coding a CT and CTA together.

First, if the intent was to perform a CTA, then only the CTA should be coded. Any non-contrast CT images taken during a CTA (i.e., for localization purposes) are considered a part of the CTA and should not be coded separately.

Second, CT and CTA can both be coded and billed only if separate full and complete studies are done.

  • What constitutes a distinct, separate technical study?

A separate set-up and separate acquisition would be one in which the patient position in the scanner is different from the first study and different acquisition parameters are used.

Documentation should clearly indicate and account for the separate technical studies performed and there should be medical necessity for each before coding for both a CT and a CTA.

A scenario where it would be appropriate to report both a CT and a CTA on the same day are for patients where a stroke is suspected, and a full and complete CT is done of the head along with CTA of the brain and/or the neck.

Clinical Examples in Radiology (Volume 4, Issue 3, Summer 2008) also offers an example where a CT reveals a tumor on the head of the pancreas and a CTA is recommended and performed on the same day for further evaluation. Of course, documentation must clearly support that the studies were full, separate and complete. And remember, just because we are able to code for it doesn’t necessarily mean everything will be paid, that is going to be based on payer policies.

So, can we code and bill for a CT and a CTA on the same day? Yes, but be sure the documentation clearly indicates full, separate studies were performed and modify as necessary.

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