Sonographic double patterns in hepatic alveolar echinococcosis according to the echinococcosis multilocularis ultrasound classification

Alveolar echinococcosis (AE) is a rare but severe zoonosis caused byEchinococcus multilocularis that predominantly affects the liver. While previous studies have focused on single ultrasound patterns, the significance of hepatic double pattern lesions is not yet fully understood. The aim of this study is to investigate the prevalence, characteristics and combinations of sonographic double patterns in AE. Based on data from Germany's national echinococcosis database (n=825),40 patients with AE and confirmed double pattern were analysed retrospectively. Inclusion criteria were patients with at least two hepatic lesions of different patterns on reference ultrasound (US). US images were evaluated using the Echinococcosis Multilocularis Ulm Classification (EMUC)-US classification, with the analysis conducted by independent, blinded sonographers. Overall, a double pattern was detected in 4.8 % of patients (n=40). Ten different pattern combinations between two different patterns were observed, with the hailstorm and ossification patterns being the most common combination (52.2 %). Pattern combinations of up to four patterns were found in a single patient. A statistically significant correlation between the pattern combination and lesion activity, as determined by ¹⁸FDG-PET/CT and serological markers, could not be demonstrated. Sonographic double pattern manifestations of AE are rare. Currently, the occurrence of specific patterns and their combinations does not correlate with lesion activity. Further studies with larger sample sizes are needed to better understand the significance of double patterns and their potential prognostic value.