Determination of vitality if liver lesions by alveolar echinococcosis Comparison of parametric contrast enhanced ultrasound (SonoVue®) with quantified 18F-FDG-PET-CT

Objective of our study is qualitative and quantitative comparison of contrast enhanced ultrasound (CEUS) and F-18-FDG PET-CT in monitoring hepatic alveolar echinococcosis (HAE). Parasitic liver lesions were examined regarding number, size, morphology, vascularization and metabolic activity. Patients, methods: 36 patients with medicallytreated HAE were included in this prospective clinical study. Abdominal ultrasound and CEUS were carried out using ultrasound contrast amplifier SonoVue(R). As part of monitoring, patients were examined by F-18-FDG-PET-CT. Quantitative analysis of CEUS was performed using the Software VueBox(TM) Quantification Toolbox. Maximum contrast enhancement in lesions peak enhancement (PE) was used as parameter. For quantification of F-18-FDG PET-CT, maximum Standardized Uptake Value (SUVmax) of lesions was specified and statistically compared with PE. Results: F-18-FDG uptake in parasitic liver lesions was diagnosed by F-18-FDG PET-CT in 32 of 36 patients. Vascularization of liver lesions was detected by CEUS in 22 of 32 FDG-positive patients with sensitivity of 69% and specificity of 100%. Mean maximum diameter of lesions was 69.5mm in CEUS and 63.7mm in B-scan ultrasound (p < 0.0001). No significant correlation was found between SUVmax and PE (p = 0.8879). Conclusion: In comparison to FDG PET-CT, the gold standard for detecting viable lesions by depicting metabolism, CEUS detects viable lesions with high specificity and moderate sensitivity by showing vascularization. CEUS must be regarded as an important tool in monitoring HAE. Dimensions of parasitic lesions are displayed more precisely through CEUS than in B-scan. With currently available methods, CEUS quantification has no benefit in monitoring HAE lesions in daily clinical practice.