Ureterovesical obstruction and megaloureter: diagnosis by real-time US.

Forty infants and children were accurately diagnosed with real-time ultrasound (US) as having megaloureter secondary to ureterovesical junction (UVJ) obstruction by an adynamic, distal ureteral segment. Characteristic US findings were dilatation of the distal ureter, often disproportionate to the appearance of the upper collecting system; lower ureteral hyperperistalsis; and a sharply tapered, incurving, distal adynamic segment, 1-3 cm long. Real-time US, used routinely in preliminary evaluation of the urinary tract in children, can facilitate early diagnosis of UVJ obstruction and thus prevent significant loss of renal function.