Contrast-enhanced ultrasound of the carotid artery in patients with large vessel vasculitis: Correlation with positron emission tomography findings

To assess the findings of contrast-enhanced ultrasound (CEUS) of carotid arteries in patients with large vessel vasculitis (LVV) and to compare them with those observed using 18F-FDG positron emission tomography (FDG-PET). METHODS: 31 consecutive patients with LVV (14 with Takayasu, 17 with giant cell arteritis with large vessel involvement) underwent both PET/CT and carotid artery colour Doppler ultrasonography (CDUS) for a total of 35 combined assessments. Right carotid artery CEUS was performed after CDUS in all assessments. Kerr's criteria, complete clinical examination and acute phase reactants were simultaneously evaluated. Intensity of vascular uptake and vascularization of carotid artery wall were compared. RESULTS: Ten FDG/PET scans showed active vascular 18F-FDG uptake (visual grade ≥2) in the right carotid artery. CEUS demonstrated severe vascularization (grade 2) within the right carotid artery wall in 12 examinations. Carotid CEUS vascularization grade significantly correlated with vascular 18F-FDG uptake (p<0.001) and max standardized uptake value (SUV) in right carotid artery/mean SUV in superior vena cava (p=0.001). When active vascular 18F-FDG uptake (≥2) was considered the gold standard for defining vascular inflammation, carotid CEUS had a sensitivity of 100% (95%CI 65%,100%) and a specificity of 92% (95%CI 72%, 99%). The positive LR was 12.5 (95%CI 3.3, 47.2). Severe vascularization at CEUS and active vascular 18F-FDG uptake were significantly more frequent in active disease according to Kerr's criteria compared to inactive (p = 0.001 and p = 0.002, respectively). CONCLUSIONS: Carotid CEUS vascularization grade and grade of vascular inflammation on FDG-PET were correlated in patients with LVV