Magnetic resonance imaging diagnosis of severe fetal renal anomalies.

OBJECTIVE: The purpose of this study was to describe magnetic resonance imaging (MRI) findings in fetuses with severe renal anomalies.

STUDY DESIGN: This was a case-control study that compared MRI findings in fetuses with suspected severe renal anomalies with gestational age-matched control fetuses. MRI was performed with T2-weighted single-shot fast-spin echo sequences. Each MRI was reviewed by an investigator who was blinded to clinical information.

RESULTS: There were 2 cases of bilateral renal agenesis, 2 cases if bilateral multicystic dysplastic kidney disease, 2 cases if unilateral renal agenesis and contralateral multicystic dysplastic kidney disease, 2 cases if polycystic kidney disease, and 2 cases of early membrane rupture/normal kidneys. Fetuses with lethal renal anomalies had a characteristic bladder appearance (signal void [dark]), whereas control fetuses had bright signal in both bladder and renal pelvis (P < .001). Both cases of early membrane rupture/normal kidneys had bright bladder signal, but 1 case did not have bright signal in the renal pelvis.

CONCLUSION: Fetuses with lethal renal anomalies had signal void in the bladder region on MRI.