To evaluate the diagnostic value of the plasma level of Echinococcus multilocularis cell-free DNA (Em-cfDNA) and contrast-enhanced ultrasound (CEUS) in hepatic alveolar echinococcosis (HAE).

40 patients with HAE admitted to the Affiliated Hospital of Qinghai University from June 2019 to December 2020 were recruited. The informed consents of all patients were obtained and the local ethical committee approval was received. Among them, 16 patients were male and24 female, aged from 8 to 65 years, with a median age of 34 years. The lesion diameter was measured from 2.1 to 17.4 cm, with a median diameter of 8.5 cm. 26 patients were diagnosed with single lesion and 14 cases of multiple lesions. 8 cases were diagnosed with early-stage lesions, 28 cases with moderate-stage lesions and 4 cases with advanced-stage lesions. The plasma Em-cfDNA levels of were determined by the next-generation sequencing and CEUS were performed in all patients. Postoperative pathological results were taken as the diagnostic gold standard to evaluate the diagnostic value of two methods for HAE. The diagnostic accuracy rates of two methods were compared by Chi-square test. The correlation between lesion diameter and plasma Em-cfDNA level was assessed by Mann-Whitney U test.

The positive rate of plasmaEm-cfDNA was 95%(38/40). The plasma level of Em-cfDNA in patients with HAE lesion diameter ≥5 cm was276(677) reads, significantly higher than 40(72) reads in patients with lesion diameter <5 cm (Z=-2.502, P<0.05). The diagnostic accuracy rate of CEUS for HAE was 90%(36/40), significantly higher compared with 70%(28/40) of conventional ultrasound (χ²=5.000, P<0.05), whereas no significant difference was noted when compared with 95%(38/40) of plasma Em-cfDNA (χ²=0.180, P>0.05).

Both CEUS and plasmaEm-cfDNA are effective diagnostic approaches for HAE.