Positron emission tomography (PET) is a nuclear medicine study that creates cross-sectional tomographic (3D) images of the metabolic activity in the patient’s tissues. The scan is performed after intravenous injection of a radiopharmaceutical. The most commonly used agent is a form of radioactive glucose known as 2-[F-18] fluoro-D-glucose or FDG. Cancers can cause abnormalities of blood flow or metabolism before structural changes are visible, and for this reason PET can often detect cancer at an earlier stage than CT or MRI. Because of their clinically proven value, most organizations have either acquired their own PET scanner or have contracted to have one located at their facility.
Because PET images do not provide anatomic detail, they are usually fused with CT taken at the same time. This allows the radiologist to pinpoint the areas of abnormal activity. CT and PET images can be fused (electronically combined) to create an image that shows the precise anatomic location of any hot spots. It is possible to fuse images that were taken on different scanners and/or at different encounters, but the image is of better quality when the patient is in the exact same position for both scans.
PET-CT scanners incorporate a PET scanner and a CT scanner in a single unit. All new PET scanners include an integrated CT scanner. The two scans are performed while the patient remains on the same table in the same position, and then sophisticated software fuses the images. There are machines that incorporate MRI images, but this article will focus solely on coding for CT technology.
The majority of oncology PET studies are reported with codes 78811-78816. The code selection is based on the extent of the scan, the type of equipment utilized and/or the use of separate and distinct imaging studies (e.g., CT). PET studies without concurrent CT are reported with codes 78811-78813. PET-CT studies are reported with codes 78814-78816.
The specific codes are shown in the quick reference table below:
The big question is can you bill for a diagnostic CT during the same encounter as a PET scan? In most cases the CT scan performed as part of a PET-CT study is used only for anatomic localization and attenuation correction. However, PET-CT scanners are capable of producing CT scans of diagnostic quality, the equivalent of a study performed on a stand-alone CT scanner, and sometimes the ordering physician will request a diagnostic CT scan in addition to the PET-CT.
The imaging facility and the interpreting physician can bill for a diagnostic CT scan together with the PET scan when:
- The diagnostic CT scan is medically necessary.
- The diagnostic CT scan is ordered by the treating physician.
- There is a separate CT acquisition (dataset) for the diagnostic CT scan. According to Clinical Examples in Radiology (Summer 2017), this typically involves administration of IV contrast and potentially multiple CT data acquisitions.
- The radiologist dictates a separate interpretation for the diagnostic CT scan. This should include the clinical indications for the diagnostic study.
Beginning in the 2018 National Correct Coding Initiative Policy Manual CMS issued a new policy on coding for diagnostic CT with PET-CT. In short, they stated when a diagnostic CT scan is performed on the PET-CT scanner, the provider must report the PET scan using a code from series 78811-78813. These codes represent PET without concurrently acquired CT. The diagnostic CT scan can be reported with the appropriate CT code, and modifier 59 or XU can be applied to the CT code. The guidance also states a CT code should not be assigned together with a PET-CT code unless the PET-CT and the diagnostic CT are performed on “separate pieces of equipment.” So, when this scenario occurs you should report the PET/CT scan with the appropriate 78814-78816 code and the diagnostic CT code. •
Melody W. Mulaik, MSHS, CRA, RCC, RCC-IR, CPC, COC, FAHRA, is the president of Revenue Cycle and Coding Strategies Inc.