Diagnosis of Echinococcosis Imaging Serologic testing Examination of cyst fluid CT, MRI, and ultrasound findings of the abdomen can be pathognomonic for cystic echinococcosis in the liver if daughter cysts and hydatid sand (protoscolices and debris) are present, but simple hydatid cysts may be difficult to differentiate from benign cysts, abscesses, or benign or malignant tumors.