Imaging findings in renal hydatid disease

The aim of this work is to describe the image findings of renal hydatid disease, especially on MR. Four cases of echinococcal involvement of the kidney were retrospectively reviewed. All patients had intravenous urography (IVU) and US performed. Computed tomography examination was available in three patients and MR in two cases. Intravenous urography demonstrated communication of the cyst to the collecting system in one case. Ultrasound revealed multicystic appearance in three cases and unilocular in one case. Computed tomography demonstrated unilocular thick-walled or multilocular cysts with well-defined walls, calcified in one case. In multilocular cysts the CT densities of the fluid of daughter cysts was significantly lower than the fluid of mother cysts. This typical appearance was present in three of our cases. The presence of a hypointense rim and a multicystic appearance were distinctive in MR imaging. The combined findings of these different imaging modalities aid greatly in establishing the correct diagnosis. Magnetic resonance imaging is of value in determining the presence of a characteristic rim and enables the evaluation of anatomical relationships.