2024 ARRS ANNUAL MEETING - ABSTRACTS

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E3421. Not Just Cancer! A Review of Nononcologic Applications of FDG PET/CT Imaging
Authors
  1. Gregory Cavanagh; The Warren Alpert Medical School of Brown University
  2. Eric Dietsche; The Warren Alpert Medical School of Brown University
  3. Jason Halpern; The Warren Alpert Medical School of Brown University
  4. Don Yoo; The Warren Alpert Medical School of Brown University
  5. Elizabeth Dibble; The Warren Alpert Medical School of Brown University
Background
On 1/1/22, the umbrella national coverage determination for Positron Emission Tomography (PET) scans by Centers for Medicare & Medicaid Services (CMS) was removed. This led the reimbursement status of PETs performed for nononcologic indications to be at the discretion of local Medicare Administrative Contractors. This presentation will review the major nononcologic uses of FDG PET given the changing coverage landscape.

Educational Goals / Teaching Points
The educational goals are to become familiar with recent changes to coverage for nononcologic PET, review the major nononcologic uses of FDG PET/CT, and recognize important imaging findings on nononcologic FDG PET/CT through representative cases.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
In 2022, CMS removed the exclusionary language from NCD 220.6 PET scans, providing an avenue for potential coverage in appropriate candidates for nononcologic PETs. We discuss the implications regarding this ruling on when PET is likely to be covered by insurance. The major nononcologic uses of FDG PET include: evaluation of fever of unknown origin (FUO), diagnosing site of infection, diagnosing and monitoring inflammatory conditions, and diagnosis and evaluation of neurologic conditions. FDG PET is useful in FUO in localization of inflammation, infection, or other fever-associated pathology when initial diagnostics have failed. We will discuss its utility in the context of a case of vasculitis. In diagnosing site of infection, FDG PET is used to identify location and sites of metastatic infection to guide further procedures/treatment. We will show illustrative cases of bacteremia with disseminated infection, active infective endocarditis, and marantic endocarditis. FDG PET proves beneficial for inflammatory conditions in identifying extent of disease and demonstrating response to treatment, and we use cases of cardiac sarcoidosis and brown tumors/hyperparathyroidism to illustrate this. For neurologic conditions, FDG PET is useful in identifying seizure foci and characteristic patterns of pathologic uptake in neurodegenerative diseases. We cover cases of Alzheimer’s disease, frontotemporal dementia, and Dementia with Lewy bodies. Compared to other nuclear medicine studies, FDG PET has benefits such as shorter examination time, high interobserver agreement, and lower radiopharmaceutical cost. Drawbacks of FDG PET include limited availability in many parts of the world and high out of pocket cost.

Conclusion
The removal of umbrella national coverage determination for PET scans by CMS in 2022 has provided an avenue for coverage of nononcologic PET scans. The major nononcologic uses of PET include evaluation of FUO, diagnosing site of infection, diagnosis and monitoring of inflammatory conditions, and diagnosis of neurologic conditions. Benefits and drawbacks to FDG PET exist compared to other nuclear medicine studies, which clinical providers and radiologists must be aware of.