Parallel echogenic "stripes", caused by contact between the parasitic ectocyst and the pericyst of the host, are very suggestive of an echinococcal origin, and usually occur with undamaged or viable cysts. If the parallel stripes disappear and the parasitic membranes collapse (serpent sign), the hydatid cyst is damaged. In contrast-enhanced CT, secondary abscess formation may be recognized if there is ring enhancement of the pericyst or if air bubbles are present within the lesion or its surroundings.

Ultrasound and CT have been used to monitor the progress of hydatid cysts undergoing medical therapy. During treatment, the cyst may be seen to undergo a metamorphosis, changing from an anechoic to a complex, and finally a "pseudosolid" pattern on sonography, owing to degradation of the cyst membranes (matrix formation) and the release of proteinaceous material. Under the effects of therapy, cysts may shrink notably and calcify, as demonstated by sonography or CT.

Magnetic resonance imaging is not as accurate in discovering calcification as compared to nonenhanced CT or ultrasound, especially if the calcification is minimal. However, the previously noted typical signs of hydatid disease can be clearly demonstrated on T1- and T2-weighted MRI. A low-intensity rim on T2-weighted images is suggestive but not pathognomonic of hydatid disease. In selected cases, contrast-enhanced studies may be done.

Early discovery of hydatid disease of the kidneys or urinary system, and differentiation from tumors or tuberculosis, is important because endocystectomy or partial nephrectomy with preservation of kidney function may be possible. When surgery is contra-indicated, chemotherapy may help to control the disease.