Diagnosis of Horseshoe Kidney Not Shown on Ultrasound But Clearly Visualized by Renal Scintigraphy

Nephrosonography was performed on a 4-day-old boy, which showed a small right kidney but did not visualize the left kidney. Renal scintigraphy was requested to assess congenital absence or ectopia of the left kidney. Renal scintigraphy with Tc-99m MAG3 revealed both kidneys, which were fused inferiorly (i.e., a horseshoe kidney). Other investigators have reported that renal scintigraphy is more accurate than sonography in identifying ectopic renal tissue.