Ultrasound imaging in cystic echinococcosis. Proposal of a new sonographic classification.

The ultrasonography permits the study of the natural history of cystic echinococcosis (CE) and evaluation of stages of the parasitic pathology. The evolution of abdominal CE was studied in 54 patients suffering from 97 abdominal cysts treated with albendazole, in 20 patients suffering from 20 hepatic cysts treated with echoguided percutaneous ethanol injection and in 39 patients suffering from 42 abdominal cysts, but left untreated. A new sonographic classification is suggested. Type I: Simple CE; (a) overall echofree; (b) with fine echos. Type II: Multiple CE; (a) multiple contiguous; (b) multiseptated with rosette, honeycomb and wheel-like pattern. Type III: With detachment of endocyst CE; (a) with double layer image; (b) with water-lily sign. Type IV: Mixed type CE; with fluid and solid aspect. Type V: Heterogeneous CE; (a) with ball of wool pattern; (b) with hypoechogenic image. Type VI: Hyperechoic CE; (a) with snow-storm pattern; (b) with dyshomogeneous aspect. Type VII: Calcified CE; (a) with advanced calcification of the layer only; (b) with calcification of overall cyst. This classification appears more appropriate to the natural history of CE and permits a better differential diagnosis and more suitable treatment.