Authors’ Response to Letter: “Diagnosis of Hepatic Hydatid Cysts by Contrast-Enhanced Ultrasound”
24 October 2019 (online)
We read the Letter to The Editor entitled “Diagnosis of Hepatic Hydatid Cysts by Contrast-Enhanced Ultrasound” relating to our recently published single-center study with appreciation . Echinococcus granulosus, causing cystic echinococcosis (CE), is a neglected zoonosis of global prevalence, with endemic distribution in the Mediterranean countries, China and Russia, parts of Africa, South America, Eastern Europe, leading to relevant socio-economic burden, high morbidity and mortality . According to the Foodborne Disease Burden Epidemiology Reference Group 2007–2015 of the World Health Organization, 19 300 deaths and about 871 000 disability-adjusted life years (DALYs) are attributed to echinococcosis annually. The resulting costs total US$ 3 billion per year . The diagnostic workup comprises sonography and serological analysis.
The purpose of our study was to evaluate the diagnostic accuracy and safety of the off-label application of CEUS during pregnancy. CEUS facilitated differentiation between various liver lesions without registration of fetal or maternal adverse effects. Doubtless, 1 case of CE in 6 included pregnant patients in the referred study is a high proportion, especially within the non-endemic area around Munich, Germany, but the included cases of rare disease conditions affecting young pregnant women at a university hospital do not represent the usual prevalence.
In previous studies it was reported that CEUS allowed for visualization of perilesional contrast enhancement as a sonomorphological correlate of perilesional inflammation indicating potentially viable manifestations of (infiltrating) alveolar echinococcosis (AE)  . To our knowledge, pericystic contrast enhancement of CE has not been described so far, which might be due to the cystic configuration with adjacent granulomatous and later fibrous tissue of CE lesions juxtaposed to the infiltrative nature of AE lesions. The different sonomorphological pattern on CEUS might be useful for differentiating CE and AE manifestations but still needs to be validated in comprehensive clinical trials. The suggested conclusion by the authors to further use CEUS in the context of abdominal screening programs for echinococcosis would exceed the scope and intention of our single-center study. As previously shown, CEUS helps to differentiate between various hepatic lesions. Whether CEUS might bring additional value in the context of echinococcosis screening programs in endemic regions with respect to the additional increasing costs needs to be evaluated on an interdisciplinary basis before being conducted.
It is essential to maintain large-scale programs including anthelminthic treatment of dogs, vaccination of lambs, culling of old and infected sheep, health education and medical surveillance, which still need to be selectively conducted and expanded in endemic areas in order to achieve prevention and elimination of CE in the future.
- 1 Schwarze V. et al. Single-Center Study: Evaluating the Diagnostic Performance and Safety of Contrast-Enhanced Ultrasound (CEUS) in Pregnant Women to Assess Hepatic Lesions. Ultraschall in Med 2019; DOI: 10.1055/a-0973-8517. . [Epub ahead of print]
- 2 Brunetti E. et al. Expert consensus for the diagnosis and treatment of cystic and alveolar echinococcosis in humans. Acta Trop 2010; 114: 1-16
- 3 WHO. Estimates of the Global Burden of Foodborne Disease, Foodborne Disease Burden Epidemiology Reference Group 2007–2015, World Health Organization. https://apps.who.int/iris/bitstream/handle/10665/199350/9789241565165_eng.pdf
- 4 Kaltenbach TE. et al. Determination of vitality of liver lesions by alveolar echinococcosis. Comparison of parametric contrast enhanced ultrasound (SonoVue(R)) with quantified 18F-FDG-PET-CT. Nuklearmedizin 2015; 54: 43-49
- 5 Schwarze V. et al. The use of contrast-enhanced ultrasound (CEUS) for the diagnostic evaluation of hepatic echinococcosis. Clin Hemorheol Microcirc 2018; 70: 449-455 . doi:10.3233/CH-189310