Ultrasonic diagnosis of renal vein thrombosis in neonates.

Ultrasound findings in four neonates with renal vein thrombosis are described. Three of the patients had unilateral involvement and one had bilateral involvement. Gray scale ultrasonograms showed the affected kidney to be enlarged. Either medium level echoes were distributed evenly throughout the kidney, or there were distinct clumps of echoes randomly scattered within the kidney, sometimes surrounding echofree spaces. The ultrasound findings, combined with appropriate clinical findings, should allow diagnosis of renal vein thrombosis without requiring invasive vascular studies.