MRI findings in a case of unilateral fetal renal vein thrombosis in a MCDA twin after fetoscopic laser photocoagluation

Fetal MRI is increasingly used to confirm prenatal ultrasound findings or to provide additional relevant information in cases of abnormal ultrasound results. Most commonly, MRI is performed to evaluate suspected central nervous system lesions. However, other fetal anomalies may also warrant further assessment with MRI. We present MRI findings in a case of unilateral fetal renal vein thrombosis (RVT) in a monochorionic diamniotic (MCDA) twin pregnancy complicated by twin-twin transfusion syndrome (TTTS). Following laser photocoagulation, a unilateral renal abnormality was detected in one of the twins during follow-up ultrasound, prompting fetal MRI. MRI findings led to the diagnosis of unilateral RVT, which was subsequently confirmed on postnatal ultrasound.