Ultrasonography of cystic renal dysplasia.

Cystic renal dysplasia, classified by Osathanondh and Potter as renal cystic disease types II and IV, is probably the result of urinary tract obstruction in fetal life. Since these kidneys function poorly, sonography plays a more significant role in their diagnosis than excretory urography. Familiarity with the sonographic spectrum of cystic renal dysplasia will help the physician to make an accurate diagnosis, and may obviate the need for unnecessary invasive procedures.