Radiology Coding Alert

Polish your skills by covering everything from modifiers to radiopharmaceuticals.

Coding positron emission tomography (PET) scans is an integral part of nuclear medicine coding, and may be a component of some diagnostic radiology coder workloads as well. However, all diagnostic radiology coders should ensure that if and when the time comes, they are more than capable of coding PET scans.

To get that process kick-started, you’re going to cover some basic principles of PET scan coding that include CPT^® codes, modifiers, and guidelines. As you’ll see, there’s a whole lot of variables and logistics to take into account that might not extend into your usual realm of diagnostic radiology coding.

Get all your pressing questions answered by working your way through this helpful tutorial on PET scan coding.

Define Terminology

A PET scan differs from other imaging services such as computed tomography (CT) and magnetic resonance imaging (MRI) scans in that it images the metabolic activity in a pathological area of affected tissue within the patient’s body. This is achieved by performing cross-sectional 3D imaging of tissue by means of an injected radiopharmaceutical agent.

This radiopharmaceutical tracer, also known as fluorodeoxyglucose (FDG), works so well at pinpointing areas of cancerous growth because of its inability to be metabolized within the cell. This results in the tracer highlighting localized areas of tissue that are higher in chemical activity. These areas of high metabolic activity typically indicate some form of disease, such as cancer. On a PET scan dictation report, you’ll see the physician make a note of the “intensity” of FDG uptake through a measurement known as standard uptake value (SUV). For example, the body of a PET scan report might reveal “markedly hypermetabolic activity in the left masseter muscle with SUV 12.6.” The radiologist may go on to elaborate as to whether a mass is associated with the hypermetabolic activity.

Compare and Contrast Code Sets

When coding for PET scans, you’ll want to take three main components into account: the PET scan, the radiopharmaceutical tracer, and the respective modifier.

For the purpose of this article, you’ll be homing in on PET body scans as represented in code range 78811-78816.

Starting with code selection, you’ve first got to confirm whether the dictation report includes a PET scan on its own or a PET scan with a concurrently acquired CT scan. For concurrently acquired CT scans, the dictation report should be clear in its elaboration that both respective scans were performed. For singular PET scans, you’ll be choosing between the following limited or whole-body codes:

• 78811 (Positron emission tomography (PET) imaging; limited area (eg, chest, head/neck))
• 78812 (…skull base to mid-thigh)
• 78813 (… whole body).

Similarly, you’ll pick between the following code set for PET scans with concurrent CT scans:

• 78814 (Positron emission tomography (PET) with concurrently acquired computed tomography (CT) for attenuation correction and anatomical localization imaging; limited area (eg, chest, head/neck))
• 78815 (… skull base to mid-thigh)
• 78816 (… whole body).

In some instances, the radiologist may perform a PET/CT fusion, or a singular PET, in addition to a separate CT scan of a localized anatomic site. In these cases, you report the respective code for the PET and/or PET/CT fusion scan in addition to the separate CT scan. While you should expect a separate report for a non-fusion PET scan performed at the same encounter as a district CT scan, you shouldn’t rule out the possibility of the separate CT existing on the same report as the PET/CT fusion. That’s because those circumstances are not entirely dissimilar from that of an ordered CT chest, abdomen, and pelvis — which you’ll often see as one fluid report.

“Because the contrast bolus is supplied just one time, there exists a very small window of time to obtain images when the contrast flows into the imaged areas of the chest, abdomen, and pelvis,” says Sabrina Goddard, CPC, billing manager at Open Imaging in Salt Lake City, Utah. “While this converts to two billing studies — CT chest and CT abdomen/pelvis — we will typically receive one report due to the fact that the image file was sent and read as a whole. This then requires another step by the coder to distinguish between the respective scans,” Goddard explains.

As you can see, these sets of codes are not only distinguished by imaging modality, but also the extent of the anatomy scanned. However, you’ve got to use extra caution when evaluating the dictation report. PET scan dictation report templates are known to cause trouble for inexperienced coders. This note of caution specifically applies to PET scans performed from the skull to the mid-thighs. Providers may use wording such as the following to describe codes 78812 and 78815, respectively:

Whole body PET scan is performed in 3 planes from the skull to the mid-thighs.

Delayed whole body Fusion PET/CT scan is performed in 3 planes from the skull to the mid-thighs.

When the provider explicitly states a whole-body scan, you should not be reporting a whole-body PET or PET/ CT fusion code if the imaging only extends to the mid-thighs. Instead, you’ll need documentation that states the following in order to report 78813 and 78816:

Delayed whole body fusion PET/CT scan is performed in 3 planes from the skull base to the distal lower extremities.

Coder’s note: Most PET and PET/CT fusion scans will be performed from the skull to the mid-thigh. For melanoma screenings or current diagnoses of melanoma, the radiologist will opt for a whole-body scan.

Take Radiopharmaceutical Code, Modifiers Into Consideration

Next, you’ve got to report the correct HCPCS code for the radiopharmaceutical tracer. These codes range from A9515-A9598. Most often, you’ll report code A9552 (Fluorodeoxyglucose F-18 FDG, diagnostic, per study dose, up to 45 millicuries) when the physician documents an FDG (fluorodeoxyglucose) injection. Most clinical encounters do not warrant the injection of more than 20 mCi (millicuries) of FDG. Since this code covers up to 45 mCi, you should report one unit.

Keep in mind: It may require a few extra steps in the billing process in order to ensure reimbursement for the radiopharmaceutical code. In Box 19 of the CMS 1500 form, you should include the invoice price in addition to the shipping price. Some payers may have more stringent requirements on how to proceed with radiopharmaceutical billing.

Finally, you’ve got to append the appropriate modifier to the respective PET or PET/CT CPT^® code. For initial treatment strategies, you’ll append modifier PI (Positron emission tomography (pet) or pet/computed tomography (ct) to inform the initial treatment strategy of tumors that are biopsy proven or strongly suspected of being cancerous based on other diagnostic testing). For subsequent treatment strategies, you’ll append modifier PS (Positron emission tomography (pet) or pet/computed tomography (ct) to inform the subsequent treatment strategy of cancerous tumors when the beneficiary’s treating physician determines that the pet study is needed to inform subsequent anti-tumor strategy).