Pictorial review of hepatic echinococcosis: Ultrasound imaging and differential diagnosis

Table 2 Sonographic features of hepatic cystic echinococcosis

WHO standardized classification	Disease course and prevalence	Sonographic features
CL	Uncertain, infertile cysts	Fundamental sign: Cystic occupations with indistinct cystic walls
Type CE1	Active, brood capsules; 21%-43%	Special sign: Double cyst wall. Secondary sign: Snowflake
Type CE2	Active, brood capsules; 4%-12%	Special signs: Nested cysts/daughter cysts (wheel-, petal-, or honeycomb-like)
Type CE3a	Transitional, the cysts begin to degenerate; 2%-8%	Special signs: Water lily, cuff sign, and ribbon
Type CE3b	Transitional, the cysts begin to degenerate; 2%-8%	Cystic and solid mass with mixed echogenicity
Type CE4	Inactive, most do not contain viable protoscolex; 10%-27%	Special signs: Ball of wool and cerebral gyri
Type CE5	Inactive, most do not contain viable protoscolex; 1%-11%	Special sign: Eggshell calcified wall

WHO: World Health Organization; CL: Cystic lesions; CE: Cystic echinococcosis.