Easily remember coding PI and PS modifier for PET scan

PET scan CPT code (Positron emission tomography) is coded very frequently in Radiology facility coding. PET scan is done to diagnose a condition or to check how condition is developing. Neoplasm can be in there initial stage or Restaging phase. These exams are not painful. PET exams help in diagnosing cancer, heart disease and epilepsy. The best advantage of PET stage compared to CT or MRI is it can tell how the patient’s body is functioning rather than just how it looks. We are here just to learn the different modifiers used with PET scan CPT code used for initial and restaging.

Modifiers for PET scan CPT code

Two modifiers PI and PS are used with PET scan CPT codes. These Modifiers are used to denote whether the disease is at initial or Restage. The study is mostly on cancer cells. The two modifier used are PI (initial staging) and PS (Restaging). There are few PET scan CPT Codes used for coding. Below are the CPT codes.

78811– Positron emission tomography (PET) imaging; limited area (eg, chest, head/neck)

78812– Positron emission tomography (PET) imaging; Skull base to Mid-thigh

78813– Positron emission tomography (PET) imaging; Whole body

78814– Positron emission tomography (PET) with computed tomography (CT); limited area (eg, chest, head/neck)

78815– Positron emission tomography (PET) with computed tomography (CT); Skull base to Mid-thigh

78816– Positron emission tomography (PET) with computed tomography (CT); Whole Body

Cpt Codes are divided as limited, skull base to mid – thigh and whole body. There is PET scan CPT Code with CT as well from 78814-16. These exams help for in getting good results. PI and PS modifiers are used with all these PET scan CPT code. It’s easy to differentiate between these codes and easy to code as well.

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Criteria f0r PI and PS to code with PET scan CPT Code

Initial staging PI modifier is added when there are signs of growth of cancer disease. For example, lung nodule, chest mass, bone lesion etc. When we have such indications for PET scan, we should use PI modifier with PET scan cpt code. For Restaging PS modifier, the report mostly mentions Restaging in the indication. But, if there is no mention of Restaging, one can check any comparison of PET given with the report. If there is a comparison given for PET report done previously we can go ahead and give PS modifier for PET scan. Since, earlier exam of PET suggest presence of initial stage previously. So, now it is again restaging. If there is no comparison, we can blindly code PI modifier with PET scan CPT Code.

Sample chart for PET scan CPT code

CPT 78815-PI

INDICATION: Carcinoma of unknown primary


HISTORY: Carcinoma of unknown Primary

COMPARISON: Chest CT from 01/18/2010.

TECHNIQUE: Prior to administration of F18-fluorodeoxyglucose (FDG), the fasting glucose level measured by the glucometer was 107 mg/dL. Approximately one hour after the intravenous administration of 16.2 mCi of F18-FDG and oral administration of contrast, emission PET images of the body were obtained from the skull base to the mid thigh. Non- contrast CT images were obtained for attenuation correction and are not of diagnostic quality and are not used to diagnose disease independently of the PET images.


Head/neck: No foci of abnormally increased FDG metabolism.

Chest: A focal area of increased FDG metabolism corresponding to distal esophagus, SUVmax 5. 8. Abdomen/pelvis: No foci of abnormally increased FDG metabolism.

Osseous structures: Multiple foci of abnormally increased FDG metabolism are noted in the visualized osseous structures including the skull base, SUVmax 10.2, right lateral mass of C2, SUVmax 14.9, posterior and lateral right rib, SUVmax 9.8 and 14.8, respectively. Expansile lytic lesion in the right lateral 2 nd rib, SUVmax 14. 8. Posterior left fourth rib, SUVmax 11. 8. T4 vertebral body, SUVmax 11. 8. Multiple additional areas of increased FDG metabolism is noted in the visualized osseous structures. Low dose CT scan was performed for attenuation correction and localization purposes. Review of the low-dose CT scan demonstrates calcified atherosclerosis in the aorta. There is thickening of the distal rectum, although no high metabolic activity is noted on the PET portion of the exam.

IMPRESSION: Multiple hypermetabolic lytic lesions involving the visualized osseous structures. There is near complete destruction of the T4 vertebral body. A tiny focus of increased FDG metabolism in the distal esophagus may be physiologic although a small neoplasm cannot be excluded with certainty.