Fetal MRI: abdominal cystic lesions.

Fetal MRI has become an essential tool for evaluating abdominal cystic lesions detected on prenatal ultrasound, offering superior soft tissue contrast and multiplanar imaging capabilities. This observational case series, conducted at Quironsalud Madrid University Hospital, analyzed fetuses diagnosed with abdominal cystic lesions who underwent fetal MRI. Lesions were classified into gastrointestinal, genitourinary, teratomatous, and syndromic categories. Fetal MRI allowed for precise lesion characterization, differentiating cystic masses from solid or mixed lesions, and identifying associated structural abnormalities. MRI findings were correlated with fetal ultrasound and, when available, postnatal imaging or surgical outcomes, demonstrating complementary information and improved diagnostic confidence compared to ultrasound alone. This improved accuracy has direct clinical implications, aiding in prenatal counseling, optimizing perinatal management, and guiding postnatal surgical planning. Our results reinforce the role of fetal MRI as a complementary imaging modality for refining the diagnosis of congenital abdominal cystic lesions and improving neonatal outcomes. CRITICAL RELEVANCE STATEMENT: This article critically evaluates the role of fetal MRI, in conjunction with prenatal ultrasound, in characterizing abdominal cystic lesions, highlighting its diagnostic advantages over ultrasound and its clinical impact on prenatal counseling, perinatal management, and postnatal surgical planning in radiological practice. KEY POINTS: Abdominal cystic lesions are frequently detected on prenatal ultrasound, but their characterization and differentiation remain challenging. Fetal MRI characterizes lesions, assesses their extent, improves classification and diagnosis, and offers superior soft tissue contrast for evaluating complex anomalies. Fetal MRI complements prenatal ultrasound, allowing a more precise assessment of lesion characteristics and facilitating prenatal counseling and perinatal planning.