Diagnostic value of fetal MRI in evaluating fetal urinary anomalies

Abstract

Purpose: To detect the accuracy of fetal MRI in diagnosing urinary tract anomalies in comparison with ultrasonographic findings and fetal outcome. Methods: We examined 30 fetuses with sonographically suspected congenital urinary tract anomalies by 2D/3D ultrasound and MRI. The gestational age range was 18–36 weeks. 43% of the women were in the second trimester. The diagnosis was confirmed by postnatal ultrasound, cystogram and biopsy in born babies and autopsy in still born or abortus fetuses. Results: We found different urinary tract anomalies including: bilateral autosomal recessive polycystic kidney disease (n = 8), unilateral autosomal recessive polycystic kidney disease (n = 1), dilated collecting system (n = 8), renal agenesis (n = 3), bilateral enlarged multicystic dysplastic kidneys (n = 5), unilateral enlarged multicystic dysplastic kidney (n = 4) and renal dysplasia (n = 1). MRI changed the US diagnosis in 6 cases and added information in 4 cases. MRI changed the patient’s management in 3 cases. MRI confirmed US diagnosis in 20 fetuses. Ultrasound was superior to MRI in one case of renal failure. Associated extrarenal anomalies were detected in 9 cases (30%). MRI showed 96% accuracy in diagnosis. Mortality rate reached 56%. Conclusion: Fetal MR imaging may be used as a complementary modality to US in diagnosing inconclusive or equivocal fetal urinary abnormality.

Keywords

• Fetal MRI
• Urinary anomalies
• Prenatal US
• Multicystic kidney
• Infantile autosomal recessive kidney disease