Can Fetal Renal Artery Doppler Studies Predict Postnatal Renal Function in Morphologically Abnormal Kidneys? A Preliminary Report

Abstract

Purpose The diagnosis of multicystic kidney in utero can be made with reasonable reliability with real-time sonography. However, a cystic hydronephrotic kidney may be difficult to distinguish from a multicystic kidney, necessitating postnatal renography. We report our preliminary observations of Doppler waveform variation in normal and cystic fetal kidneys. Materials and Methods Five consecutive fetuses with a unilateral cystic kidney, and one with a unilateral hydronephrotic duplex kidney and cystic upper moiety were evaluated in utero with color Doppler renal sonography. Results Doppler signal on serial ultrasound was consistently absent in the ipsilateral cystic kidney, while normal renal artery Doppler waveforms with a systolic and diastolic component were obtained from the contralateral and unaffected moieties. Postnatal renography confirmed nonfunction in all cystic moieties. The hydronephrotic noncystic moiety of the duplex kidney showed a normal Doppler waveform and good function. Conclusions Absence of renal artery Doppler waveforms in fetal cystics kidneys correlates with renal nonfunction. If this observation can be further confirmed by additional cases, fetal Doppler sonography would become an additional too to diagnose confidently a multicystic kidney in utero, which may allow us to dispense with postnatal renography.