Contrast-Enhanced Ultrasound of the Carotid Artery in Patients With Large Vessel Vasculitis: Correlation With Positron Emission Tomography Findings.

OBJECTIVE: 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 18 F-fluorodeoxyglucose-positron emission tomography (18 FDG-PET).

METHODS: A total of 31 consecutive patients with LVV (14 with Takayasu arteritis, 17 with giant cell arteritis with large vessel involvement) underwent both PET/computed tomography and carotid artery color Doppler ultrasound (CDUS) for a total of 35 combined assessments. Right carotid artery CEUS was performed after CDUS in all assessments. Kerr's criteria, a complete clinical examination, and acute phase reactants were simultaneously evaluated. The intensity of vascular uptake and vascularization of the carotid artery wall were compared.

RESULTS: Ten 18 F-FDG/PET scans showed active vascular 18 F-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. The carotid CEUS vascularization grade significantly correlated with vascular 18 F-FDG uptake (P < 0.001) and maximum standardized uptake value (SUV) in the right carotid artery/mean SUV in the superior vena cava (P = 0.001). When active vascular 18 F-FDG uptake (≥2) was considered the gold standard for defining vascular inflammation, carotid CEUS had a sensitivity of 100% (95% confidence interval [95% CI] 65-100) and a specificity of 92% (95% CI 72-99). The positive likelihood ratio was 12.5 (95% CI 3.3-47.2). Severe vascularization at CEUS and active vascular 18 F-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).

CONCLUSION: Carotid CEUS vascularization grade and the grade of vascular inflammation on 18 F-FDG-PET were correlated in patients with LVV.