OP21.06: Fetal renal pelvis volume assessed by three‐dimensional ultrasonography and neonatal outcome: initial experience

Abstract

The aim of this study was to evaluate fetal renal pelvis volume measurements in hydronephrotic kidneys using three-dimensional (3D) ultrasonography as a predictor of neonatal urological malformations and the need for surgery. In this prospective study the fetal renal pelvis volume was measured using 3D ultrasonography in 88 kidneys of 49 fetuses with hydronephrosis (anteroposterior diameter > 4 mm) in the third trimester of pregnancy. After volume acquisition, volume calculation with manual delineation of the fetal renal pelvis was assessed using the Virtual Organ Computer-aided AnaLysis (VOCAL™) program. Two postnatal groups were defined: (1) no surgery required or no significant uropathies, (2) significant uropathies and/or surgery required. Positive predictive values on the risk of surgical intervention or uropathies were calculated. In 36 neonates (73%) the diagnosis of hydronephrosis was excluded postnatally or no significant uropathies were diagnosed. Eight (16%) neonates had significant uropathies and surgical intervention was needed in five (10%) of the infants. Fetal renal volume measurement > 5.0 cc demonstrates a positive predictive value of 100% of cases in need of surgery and allows identification of 63% of the cases with significant uropathies. These preliminary data on 3D fetal renal pelvis volume measurements using the VOCAL™ program are the first presented to our knowledge and indicate that it is potentially an accurate method for the assessment of fetal renal pelvis volume as a predictor for the risk of surgical treatment or significant uropathies postnatally. It seems that postnatal follow-up is warranted if fetal renal pelvis volume is > 5.0 cc in the third trimester of pregnancy. An additional (already planned) control group can identify the best cut-off value to further optimize these novel data.