Evaluation of Hydronephrosis in Pregnancy using Ultrasound and Renography

Abstract

The value of ultrasound and 131-Hippuran renography for diagnosing hydronephrosis during pregnancy was investigated. In a control series of 31 symptom-free pregnant women the ultrasonographically measured renal pelvic diameters in the three trimesters were 5, 10 and 12 mm on the right side and 3, 4 and 5 on the left, respectively. In ten healthy non-pregnant women the pelvic diameter varied from 3 to 9 mm on the right side and from 2 to 6 mm on the left side when measured during antidiuresis and water diuresis. Out of 35 pregnant women complaining of flank pain, 31 showed an increased renal pelvic diameter. These 35 women also underwent renography on the same day as the ultrasound examination. In 6 of 27 pregnant women with right-sided pain and in 3 of 8 with left-sided pain, diuresis renography indicated acute ureteral obstruction and in 6 of these 9 patients impairment of renal parenchymal function was also evident. In some cases the impaired renal function was fully reversed after surgical intervention. It is concluded that ultrasound investigation of the kidney is a valuable method for screening prior to renography. Since the negative prediction value of using 17 mm as the upper limit of the pelvic diameter was 100%, patients with a smaller pelvic diameter may not need to be referred further for renography or urography, and radiation will thus be minimized. On the other hand, renography is indicated when the pelvic diameter is more than 17 mm in patients complaining of flank pain. Renography provides information not only concerning acute uretral obstruction but also with regard to parenchymal function, which is valuable for the decision regarding surgical intervention.