Usefulness of bubble study in echocardiographic diagnosis of contained rupture of hydatid cyst in the right ventricular outflow tract.

We describe an adult female presenting with dyspnea in whom both transthoracic and transesophageal echocardiography detected a mobile sac-like structure in the right ventricular outflow tract (RVOT) containing a heterogenous echogenic mass. This sac-like structure markedly changed its shape and size during the cardiac cycle. These findings and the fact that the patient lived in a rural area raised the possibility that this was a hydatid cyst. A bubble study using normal saline was useful in detecting a contained rupture of the cyst. Bubble echoes were noted within the sac-like structure but did not penetrate the inner wall of the cyst which contained echogenic material, indicating that the rupture was confined only to the outer layers. At surgery, a 0.5 cm communication was noted between the cyst and the RVOT and pathology confirmed the diagnosis of hydatid cyst.