ARRS 2022 Abstracts

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E2133. Role of PET/CT in the Imaging of Aortic Diseases
Authors
  1. Meng Geng; Cedars Sinai Medical Center
  2. Susan Win; Cedars Sinai Medical Center
  3. Kavish Gupta; Cedars Sinai Medical Center
  4. Kevin Hoang; Cedars Sinai Medical Center
Background
Aortic diseases include acute aortic syndromes, aortic aneurysms, atherosclerosis, inflammatory diseases, and aortic tumors. While PET/CT is the mainstay in evaluation and staging of malignancy, there is emerging role for this imaging modality in evaluation of aorta. In addition to CT, which is the standard imaging for evaluation of aortic disease, addition of the PET component provides function and molecular information that can help in evaluating the etiology and severity of underlying disease. There is increased metabolic activity, which can be seen in platelet activation or inflammatory activity. It has high sensitivity for detecting active inflammation in patients with elevated inflammatory markers and can be helpful in patients where there is high degree of clinical suspicion for vasculitis with nondiagnostic biopsy results. Additionally, it is helpful in detecting arterial territories and extra-vascular involvement. Follow-up imaging with PET/CT can help monitor therapeutic responsiveness and disease relapse, thereby playing a valuable in dictating clinical management.

Educational Goals / Teaching Points
The educational goals for this presentation are to review the different pathologies that can affect aorta; review the common imaging modalities used for evaluation of aorta; recognize findings on PET/CT of these pathologies and most importantly; and elucidate the role of PET/CT in the diagnosis, prognosis, and monitor of treatment response.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
For PET/CT, there is increased uptake of 18-FDG in WBC, which can be seen in platelet activation or inflammatory activity. In acute aortic syndrome, PET/CT is typically not the initial imaging modality of choice due to the time to acquisition. However, it can provide useful information in detecting underlying inflammatory activity as elevated metabolic activity is associated with increased risk of disease progression. In patient status post-aneurysmal repair, PET/CT can also be used to follow aneurysm progression. In large vessel vasculitis, PET/CT can be used to check for arterial territories involved and extra-arterial involvement. In rheumatoid vasculitis, there is diffuse increased uptake throughout the entire aorta and bilateral subclavian, carotid, iliac, and femoral arteries, suggestive of extensive vasculitis. Some limitations of PET/CT include reimbursement fees, limited spatial resolution, which can limit visualization of small vessel involvement, and prolonged scan time.

Conclusion
In conclusion, PET/CT combines the high resolution of CT with functional information of PET, thereby providing valuable structural and molecular activity information. PET/CT should be indicated when an inflammatory or neoplastic process is suspected. It can also be valuable in acute aortic syndromes outside of emergency settings. This can help elucidate the underlying etiology, prognosticate, and monitor progression or treatment response.