AB1550 UTILITY OF WHOLE-BODY 18F-FDG PET-CT IN THE DIAGNOSIS OF NEUROSARCOIDOSIS

Abstract

BackgroundNeurosarcoidosis (NS) is one of the most severe manifestations of sarcoidosis [1].NS diagnosis is difficult since clinical features and cranial imaging findings are often unspecific and central nervous system biopsy is unfrequently performed. Flourine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET-CT) is emerging as a powerful tool for the evaluation of sarcoidosis. Data on the role of 18F-FDG PET-CT in NS is scarce.ObjectivesTo assess the utility of 18F-FDG PET-CT in patients with suspected NS.MethodsPatients diagnosed with sarcoidosis at a University hospital in Northern Spain, between January 1999 and December 2019 were assessed. Sarcoidosis was diagnosed according to ATS/ERS/WASOG criteria as follows: compatible clinical and radiological presentation, histopathologic confirmation, and exclusion of other granulomatous diseases. NS was diagnosed according to the NS Consortium Consensus Group [2].Receiver Operating Characteristic (ROC) curve for Chest Computed Tomography (CT) and 18F-FDG PET-CT were compared.ResultsNS was suspected in 30 (19 women/11 men) patients out of 384 (7.8%) (mean age; 55.0±15.8 years). The underlying neurological manifestations were chronic headache (n=13; 43.4%), peripheral neuropathy (n=6, 20%), cranial neuropathy (n=5, 16.7%), spinal cord abnormalities (n=3, 10%) and aseptic meningitis (n=3, 10%). Complementary study’s findings are described inTable 1.18F-FDG PET-CT was performed in 10 (33.4%) patients. 18F-FDG PET-CT were abnormal in 9 (90%) patients. Abnormalities suggestive of NS were found in 7 (70%) patients. These were located in lymph nodes (n=7, 100%), parotid gland (n=1, 14.3%) and bone (n=1, 14.3%). Other abnormalities were found in 2 (20%) patients in vocal cord (n=1, 50%) and rectum (n=1, 50%). Only 1 (10%) patient had no abnormalities in 18F-FDG PET-CT. All patients (n=2, 100%) in which chest radiography and chest CT were negative, had pathological findings suggestive of NS in 18F-FDG PET-CT. After whole-body 18F-FDG PET-CT, all patients with accessible abnormalities suggestive of sarcoidosis underwent biopsy in lymph node (n=5, 71.4%), parotid gland (n=1, 14.3%) and skin (n=1, 14.3%). In all of them non-necrotizing granulomas were found. 18F-FDG PET-CT and chest CT diagnostic ability was compared (Figure 1). 18F-FDG PET-CT had a higher Area Under the Curve (AUC) (0.94 [95% CI: 0.78-1]) than chest CT (0.75 [95% CI: 0.28-1]).Conclusion18F-FDG PET-CT seems to be a useful tool in the evaluation of patients with suspected NS specially when the chest CT is negative or inconclusive.