Introduction Fetal MRI began to be used as an imaging modality in 1983 and was introduced as part of research in 1998 in this tertiary centre. Most papers suggest that fetal MRI is a valuable adjuvant to ultrasound imaging. This is the first known research study from the UK and is the only five years duration retrospective review in literature assessing the impact of fetal MRI on antenatally suspected renal anomalies.

Methodology This retrospective study on fetal MRI was based at the Fetal MRI department of a tertiary referral centre. The study was conducted from October 2015 to December 2016 and included all referrals for fetal MRI, from October 2011 to September 2015. A total of 578 patients were identified and out of which 80 were referrals due to renal concerns in the fetus on antenatal ultrasound scan. The results of the fetal MRI scan, antenatal and postnatal ultrasound were compared with assess the impact on the outcome of the pregnancy. The gold standard of comparison was postnatal renal ultrasound imaging.

Results Out of the 80 referrals, there were four terminations, three stillbirths, nine neonatal deaths and of the rest of the 64 referrals, outcome data was available in 27 pregnancies. Comparable results between antenatal ultrasound imaging and fetal MRI were provided in 26% of the pregnancies. Fetal MRI changed the diagnoses in 31.25% and also provided additional information in 42.5% compared with those who had antenatal ultrasound imaging. In 12.5%, the additional information provided by fetal MRI could have impacted the management of these pregnancies and of these almost 90% provided additional information on nonrenal related systems. Of the 7 pregnancies where antenatal USG diagnoses differed from postnatal diagnoses, 4 had accurate fetal MRI diagnoses. The positive predictive value for fetal MRI in this study was 88.9% compared with 74% for antenatal ultrasound renal imaging.

Conclusion Fetal MRI is thought to have led to a major impact on the outcome of the pregnancies by leading to a change in the diagnosis in 31.25% of the study cohort and by providing additional information that could have impacted on the management of 12.5% of the pregnancies.