Innovations in Imaging: 18F-Fluorodeoxyglucose PET/CT for Assessment of Cardiovascular Infection and Inflammation

Abstract

Purpose of review: ¹⁸F-Fluorodeoxyglucose positron emission tomography (PET) combined with computed tomography (CT), referred to as ¹⁸F-FDG PET/CT, plays a significant role in the diagnosis and management of patients with systemic infectious and inflammatory conditions. This review provides an overview of ¹⁸F-FDG PET/CT in systemic infectious and inflammatory conditions, including infective endocarditis (IE), cardiac implantable electrical device (CIED)/left ventricular assist device (LVAD) infection, sarcoidosis, and large-vessel vasculitis (LVV).

Recent findings: This review highlights the past and present literature in the increasing role of ¹⁸F-FDG PET/CT in cardiovascular inflammation and infection, including diagnostic and prognostic findings. They key aspects of this paper are to highlight the importance of ¹⁸F-FDG PET/CT in cardiovascular infection and inflammation, and to provide illustrations of how it can contribute to patient diagnosis and management.

Keywords: 18F-FDG; Cardiac Imaging; Cardiovascular Infection; Inflammation; Nuclear Cardiology; PET/CT.

Fig. 1

Aortic prosthetic valve infective endocarditis. A 52-year-old female presented with fever and bacteremia in the context of a mechanical aortic valve. A ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET/CT imaging study was acquired, obtaining images from the vertex of the skull through the toes, followed by a dedicated cardiac bed acquisition. Fusion and PET images are displayed, images A and B correspond to the axial plane, images C and D correspond to the coronal plane, and images D and E are images oriented to the aortic valve plane. There is intense semi-concentric uptake along the ring of the mechanic aortic valve, higher along the left portion of the valve, concerning for mechanical aortic valve infective endocarditis (white arrows on fusion images and black arrows on PET images). Additionally, there is increased bone marrow and splenic uptake, most likely related to the underlying inflammatory/infectious systemic process (white asterisks on images C and D)

Fig. 2

CIED pocket and lead infection diagnosed by ¹⁸F-FDG PET/CT. Coronal PET images (panel A) show multiple areas of focal, heterogeneous, intense ¹⁸F-FDG uptake surrounding the ICD generator (standardized uptake value, SUV_max 4.8, red arrow), along the ICD leads (SUV_max 6, green arrow) and associated with the ICD leads in the right atrium (SUV_max 5.9, blue arrow). Uptake persisted on non-attenuation corrected images (not shown). Fusion with CT (panel B) confirm the anatomic localization. These findings confirmed CIED deep pocket infection with lead involvement. (Adapted from Bourque et al. Journal of Nuclear Cardiology. 2024(34):101786, with permission from Elsevier) [6]

Fig. 3

Serial ¹⁸F-FDG PET/CT imaging to diagnose cardiac sarcoidosis and assess response to therapy. A 67-year-old female with a history of pulmonary sarcoidosis presents with an episode of paroxysmal ventricular tachycardia after three weeks of dyspnea on exertion and orthopnea. She underwent positron emission tomography/computed tomography with ¹⁸F-fluorodeoxyglucose (FDG) to assess inflammation and ¹³N-ammonia to evaluate perfusion (A). Imaging revealed a high concern for active inflammation from cardiac sarcoidosis with prominent heterogeneous ¹⁸F-FDG uptake in the apical to basal anteroseptum, inferoseptum, and inferior walls and associated perfusion defect in the same territory. She was started on prednisone and transitioned to mycophenolate mofetil and heart failure goal-directed medical therapy. She had resolution of her symptoms. Repeat imaging at 3 months showed complete resolution of her ¹⁸F-FDG uptake consistent with disease remission (B). She was able to taper off therapy successfully

Fig. 4

Active large vessel vasculitis. A 63-year-old female with a recent diagnosis of giant cell arteritis had an ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET/CT performed to assess for extent/activity of disease elsewhere. A Vasculitis FDG PET/CT was performed from vertex of the skull through the mid thighs, with a dedicated head and neck bed acquisition. Panel 1: Fusion and PET images are displayed, images A and B correspond to the axial plane at the level of ascending and descending aorta, while images C and D are oriented to the thoracoabdominal aorta. There is concentric FDG uptake along all the segments of the aorta (Images A-D, white arrows on fusion images and black arrows on PET images), consistent with active vasculitis. Panel 2: Fusion and PET images of the head and neck are displayed, images E and F correspond to the axial plane at the level of common carotid arteries, while images G and H correspond to the coronal plane. There is abnormal FDG uptake along the common carotid arteries (Images E-H, white arrows on fusion images and black arrows on PET images), consistent with active vasculitis of the common carotid arteries in the context of known giant cell arteritis