B-Scan Ultrasound in the Diagnosis of Hydronephrosis

Thirty-four kidneys in 26 patients demonstrating all grades of hydronephrosis were examined with B-scan ultrasound. In moderate hydronephrosis, the pelvic echo pattern has a C, ring, or ovoid shape. Severe hydronephrosis may be recognized by (a) a series of cyst-like echo patterns radiating from the pelvis or (b) the development of a featureless, sonolucent sac. In ureteropelvic junction obstruction, a “figure 8” double-circle pattern may occur.