Prenatal diagnosis of genital anomalies with MRI: A case series

Introduction: Fetal magnetic resonance imaging (MRI) is commonly used as an adjunct to prenatal ultrasound (US) in identifying genitourinary abnormalities, but there is no data regarding its accuracy when identifying genital anomalies. To address this gap, this study reviewed our experience with identification of genital anomalies on fetal MRI and the correlation between fetal MRI findings and postnatal diagnosis. Case Series: An Institutional Review Board (IRB) approved retrospective review was conducted for patients with genital abnormalities noted on fetal MRI. Patients were excluded if the anomaly required no perinatal management steps, such as an isolated foreshortened phallus or due to an unrelated anomaly such as bladder exstrophy. The data collected included patient and maternal demographics, gravida status, prenatal ultrasound and fetal MRI findings, postnatal diagnosis, early postnatal course, and subsequent management. In this series of five patients with clinically significant genital findings on fetal MRI, two patients’ fetal MRI findings were confirmed by postnatal physical exam and/or imaging. Among the two patients with hypospadias in this series, only one was correctly diagnosed on fetal MRI and received postnatal follow-up by urology. Ambiguous genitalia were read in three patients’ fetal MRI with one of those confirmed postnatally. Two of these three patients underwent early rule-out congenital adrenal hyperplasia based on fetal MRI. Conclusion: A low percentage of patients with genital abnormalities received accurate prenatal diagnosis by fetal MRI. Fetal MRI may not provide an accurate diagnosis for prenatally detected genital findings but may serve as an additional data point to inform early postnatal diagnostics and level of care for patients with syndromic findings, such as ambiguous genitalia associated with congenital adrenal hyperplasia.