Ultrasonography in the diagnosis of hydronephrosis in patients with normal renal function

In order to define the sensitivity and specificity of ultrasonography (US) in the diagnosis of hydronephrosis, 125 patients with normal renal function were examined after urography using high-resolution real-time scanning. The overall diagnostic accuracy of US in detecting hydronephrosis was 85.2%, with a specificity of 84.4% and a sensitivity of 89.9%. It is concluded that US may be considered the screening test of choice for the diagnosis of hydronephrosis. However, urography is still required for the evaluation of renal function, site, and nature of the obstruction when US shows a dilated collecting system and in the patient with a normal US but renal colic.