The role of PET in the management of sarcoidosis

Abstract

Purpose of review: PET has emerged as method to determine the location and extent of disease activity in sarcoidosis. As most clinicians do not routinely utilize PET in the management of sarcoidosis, an understanding of the imaging technique is needed to comprehend the impact that PET abnormalities have on diagnosis, prognosis, and treatment.

Recent findings: Although PET can detect inflammation because of sarcoidosis throughout the body, it is most often utilized for the diagnosis of cardiac sarcoidosis for which it may provide information about prognosis and adverse events. Whenever PET is combined with cardiac magnetic resonance (CMR), clinicians may be able to increase the diagnostic yield of imaging. Furthermore, PET abnormalities have the potential to be utilized in the reduction or augmentation of therapy based on an individual's response to treatment. Although various biomarkers are used to monitor disease activity in sarcoidosis, an established and reproducible relationship between PET and biomarkers does not exist.

Summary: PET has the potential to improve the diagnosis of sarcoidosis and alter treatment decisions but prospective trials are needed to define the role of PET while also standardizing the performance and interpretation of the imaging modality.

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FIGURE 1

Axial and coronal views of PET scan in patient with cardiac sarcoidosis. Methods: this is an original PET image from the authors’. Results: panel a shows disease activity in the left apical (SUV of 22.6) and septum (SUV of 21.6). Panel b shows a reduction in SUV after treatment (SUV 4.2 and 5.7 respectively). Panel c shows apical and septal disease in the coronal view.

FIGURE 2

Pulmonary parenchymal changes because of sarcoidosis on computed tomography and corresponding PET findings. Methods: this is an original PET image from the authors. Results: the top image was obtained from computed tomography and shows parenchymal architectural changes while the bottom image shows increase FDG uptake by PET in the corresponding location.

FIGURE 3

FDG-PET findings in multisystem sarcoidosis. Methods: this is an original PET image from the authors. Results: the image on the left demonstrated FDG uptake in the heart while the image on the right reveals multisystem disease involving the liver, spleen, right acetabular bone, and lymph nodes in the low cervical, supraclavicular, mediastinal, and hilar regions. Both images are from the same individual at different rime intervals of the disease course.

FIGURE 4

Consecutive FDG-PET scans in patient with multisystem sarcoidosis. Methods: this is an original PET image from the authors’. Results: this figure shows three consecutive FDG-PET performed in a patient with progressively more aggressive therapy for sarcoidosis.