Logo: to the web site of Uppsala University

Abstract 

Background: Vasculitis is a heterogeneous group of autoimmune diseases that involve inflammation of the blood vessel walls. The inflammation affects the cranial and extracranial sites, which can cause headaches, fatigue, pain in the jaw muscles and, in more severe cases, aneurysm.

Aim: This retrospective study examined 37 patient cases from 1/2023 - 1/2024 and aimed to apply the Meller scale in the diagnosis of vasculitis. This study will form the basis for a future study in which a group of patients with vasculitis issue will carry out the examination one hour and three hours respectively after the injection of the tracer.

Method: The disease is diagnosed with the 18F-FDG PET/CT method by taking images after the injection of the radioactive tracer for 180 minutes. Inflammatory cells require more energy, therefore they will take up more radioactive sugar and accumulate there, which makes it possible to detect inflammation. 

Results: The results showed that the method18F-FDG PET/CT with positive vasculitis grade 2 and 3 had 100% sensitivity and 70% specificity, while results with only positive vasculitis as grade 3 showed sensitivity 50% and specificity 96%. 

Conclusion: 18F-FDG PET/CT is an effective method for evaluating vasculitis, but the diagnosis is challenging and requires consideration of several factors such as ongoing steroid treatment and atherosclerosis. Further studies with a larger number of patients are needed to optimize the timing of image acquisition and avoid false positive and negative results.