Whitaker test is done for diagnosing which of the following condition?

Whitaker test is used to diagnose hydronephrosis. In this test a percutaneous puncture is made through the loin and fluid is infused at a constant rate with monitoring of intrapelvic pressure. If there is an abnormal rise in pressure that indicates presence of obstruction which accounts for the hydrocephalus. Ultrasound is the least invasive method of diagnosing hydrocephalus, and is used to diagnose pelviureteral junction obstruction in utero. Excretion urography is helpful in diagnosing if the obstructed kidney is still functioning. Isotope renography is the most helpful test to establish that dilatation of the renal collecting system is due to obstruction. Ref: Bailey and Love's sho practice of Surgery, 24th edn, Page 1315