RT Journal Article SR Electronic T1 Diagnosis of vasculitis with F-18 FDG-PET/CT: Quantification of arterial wall activity in vasculitis patients and controls JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 224P OP 224P VO 48 IS supplement 2 A1 Mark Mueller A1 Jörg Henes A1 Christina Pfannenberg A1 Roland Bares A1 Matthias Reimold YR 2007 UL http://jnm.snmjournals.org/content/48/supplement_2/224P.4.abstract AB 1069 Objectives: F-18-FDG-PET-CT has been shown to be suitable for the diagnosis of vasculitis. To estimate the metabolic activity of the arterial wall, a visual score in comparison to the liver uptake has been proposed. This study evaluates quantitative PET methods. Methods: Vasculitis group (VASC): 21 Patients (20–80 ys., 18f) with proven or suspected vasculitis and elevated FDG uptake in arterial walls. Control group (CONT): 20 oncologic patients (25-79 ys., 14f) without pathologic PET findings. Visual score: 0:Arterial wall not visible; 1:wall<liver; 2:wall=liver; 3:wall>liver. Quantification: SUV of the arterial wall and ratios to liver or blood pool (right atrium). 70% isocontour (3D) in the aortic arch(AA), thoracic and abdominal aorta (TA, AbA), carotic and vertebral arteries (CA), subclavian arteries and brachiocephalic trunc (SA), iliacal, and femoral arteries (IA, FA). Because of a lack of a gold standard,the SUV of VASC and CONT was compared (rank sum test). Results: In the VASC and CONT, an overlapping range of SUV was found for most of the arterial regions (except AA, p<0.05 and AS, p< 0.01, higher SUV in VASC). A better separation could be achieved when liver ratios where used (p<0.05 or less in all areas, VASC higher) or with blood pool ratios for the aorta (p<0.05 or less,VASC higher). A strong correlation was found between visual score with SUV in the arteries, with liver ratios and blood pool ratios (rho>0.8 AA each method). Conclusions: For the detection of vasculitis liver ratios appear to be particularly helpful. A positive correlation between arterial wall and liver uptake in the CONT (AA:R2=0.54) and not in the VASC (AA:R2=0.0008) contributes to this finding. Differences of liver uptake between patients and controls should be analyzed because they might reduce the reliability of liver ratios and the visual score. Use of SUV of arterial walls alone can lead to a high rate of a false positive diagnoses of vasculitis. The reliability of different quantitative methods for therapy monitoring has to be evaluated.