Abstract
18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) can detect vascular inflammation in large-vessel vasculitis (LVV). Clinical factors that influence distribution of FDG into the arterial wall and other tissues have not been characterized in LVV. Understanding these factors will inform analytic strategies to quantify vascular PET activity. Patients with LVV (n = 69) underwent 141 paired FDG-PET imaging studies at one and two hours per a delayed image acquisition protocol. Arterial uptake was quantified as standardized uptake values (SUVMax). SUVMean values were obtained for background tissues (blood pool, liver, spleen). Target-to-background ratios (TBRs) were calculated for each background tissue. Mixed model multivariable linear regression was used to identify time-dependent associations between FDG uptake and selected clinical features. Clinical factors associated with FDG distribution differed in a tissue- and time-dependent manner. Age, body mass index, and C-reactive protein were significantly associated with arterial FDG uptake at both time points. Clearance factors (e.g. glomerular filtration rate) were significantly associated with FDG uptake in background tissues at one hour but were weakly or not associated at two hours. TBRs using liver or blood pool at two hours were most strongly associated with vasculitis-related factors. These findings inform standardization of FDG-PET protocols and analytic approaches in LVV.
Highlights
Recent consensus guidelines on the role of FDG-positron emission tomography (PET) in large-vessel vasculitis (LVV) offered few evidence-based recommendations about the use of semiquantitative analysis to measure vascular FDG uptake[8]
Inter- and intra-rater reliability was excellent for contouring of the arterial wall and all background tissues: blood pool, liver, and spleen (Supplementary Figs 1 and 2)
This study is unique in that factors associated with FDG distribution were studied in a time-dependent and tissue-specific manner in a cohort of patients with LVV
Summary
Recent consensus guidelines on the role of FDG-PET in LVV offered few evidence-based recommendations about the use of semiquantitative analysis to measure vascular FDG uptake[8]. Most evidence supporting these recommendations was based on studies in atherosclerosis rather than LVV8,15. Recommendations included normalization of arterial FDG uptake to blood pool and acquisition of images at a minimum of 60 minutes after radiotracer injection. This study employed a unique design; whereby, sequential FDG-PET images were obtained in the same patients one and two hours after a single injection of FDG
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
