Radiological signs of hydatid cysts

 Unruptured cysts: 

 1) Daughter Cysts (Multivesicular Cysts): Smaller cysts (daughter vesicles) are seen within the larger mother cyst. This can create various appearances like 

 2) Honeycomb, Wheel Spoke, Rosette, Racemose pattern, Cartwheel appearance

 3) Double-Line Sign (US):, USG of  unruptured cysts may show a double-layered wall representing the pericyst and the laminated cyst membrane.

4) Hydatid Sand/snowstorm sign: Fine echogenic foci within the cyst, representing protoscolices, may be seen on ultrasound, sometimes described as a when they settle dependently with patient repositioning.

 Partially or Completely Ruptured Cysts:

5) Air Crescent Sign: A crescent-shaped rim of air seen at the superior aspect of the cyst, typically when the cyst erodes into an adjacent bronchus or bronchiole, and air becomes trapped between the pericyst and the laminated membrane of the endocyst.

 6) Cumbo Sign/Onion Peel/ Double Arch Sign: Curvilinear membranes outlined by air both inside the endocyst and a crescent of air between the endocyst and pericyst.

 7) Water Lily Sign (Camalote Sign): Collapsed or detached membranes floating at the air-fluid interface within the cyst, resembling a water lily. This indicates complete rupture and degeneration of the cyst.

 8) Empty (Dry) Cyst Sign: An air-filled cavity remaining after the expectoration of membranes and fluid.

 9) Serpent Sign (Snake Sign): Wavy, detached membranes floating within the cyst, appearing like a snake or twisted ribbon.

 10) Whirl Sign (Spin Sign): Twisting membranes within the cyst, indicating partial rupture.

 11) Ball of Wool (Yarn, Congealed Water Lily, Mass within a Cavity) Sign: A solid conglomeration of membranes settled in the dependent portion of the cyst