Hydatid disease of the urinary tract: evaluation of diagnostic methods.

Eight patients with histologically proven hydatid disease of the urinary tract underwent eosinophil count, ultrasonography (US) and computed tomography (CT). The findings were compared with those in 8 age-matched controls with simple renal cysts. Eosinophilia was not significantly different in the 2 groups. Mixed echogenicity on US and multivesicular cyst with mixed density on CT were the diagnostic features of hydatid cysts. Using these factors, both US and CT could diagnose or exclude hydatid disease in a significant number of patients with renal cysts. However, CT was more sensitive (88 vs 50%) and accurate (94 vs 75%) than US in the diagnosis of urinary tract hydatid disease. Retrograde pyelography confirmed communicating renal hydatid cysts in 2 patients. A practical algorithm for the investigation of urinary tract hydatid disease is suggested.