The utility of renal medullary pyramidal thickness measurements on the first and second postnatal ultrasound in infants with congenital hydronephrosis.

For the group overall, a smaller PT on both the first and second ultrasound was associated with increased risk of pyeloplasty, however, a PT obtained on an ultrasound prior to 3 days of life was not demonstrated to be predictive. Of note, PT was predictive in this same group of patients on their second ultrasound. A PT of <3 mm on an ultrasound obtained beyond 3 days of life was associated with higher risk of pyeloplasty. The PT ratio of hydronephrotic to normal contralateral kidney of the children who had their first ultrasound after 3 days of life was also significant in predicting the odds of having surgery. In addition, a decreasing PT between the first and second ultrasound was also identified as a risk factor for pyeloplasty.