By definition, antenatal MRI is the MR imaging during state of gestation without causing any significant risk to ongoing pregnancy and the fetus. MRI is in a unique advantageous position during antenatal period where ultrasound often provides limited information and CT is usually avoided due to radiation-related risks. The indications of antenatal MRI can be sub-divided into fetal indications, maternal obstetric indications and maternal non-obstetric indications. Antenatal MRI offers better anticipation of prognosis and facilitates parental counseling by accurate characterization of disease process and detection of concomitant anomalies. Ultrasound will however, remain the primary fetal imaging modality and MRI is not likely to replace its role in fetal imaging because of the proven utility, widespread availability and relatively low cost of ultrasound. But under specific clinical conditions, where Ultrasound does not provide adequate information, MRI is bliss and is a useful adjunct to ultrasound.

The specific clinical indications where MRI proved to be more useful include fetal anomaly screening in high risk/precious pregnancy, oligohydramnios / maternal obesity, fetal CNS assessment, characterization of fetal mass, assessment of fetal spine, delineation of fetal alimentary tract and other abdominal viscera, conjoint twin assessment, prior to antenatal intra-uterine fetal surgery or ex-utero intrapartum procedure. MRI indications which are presently at relatively experimental stage include non-invasive MR spectroscopy to detect antenatal fetal hypoxia and lung maturity status. Apart from this, the role of Diffusion-weighted MRI in antenatal imaging of placenta and fetal kidneys/lungs is also likely to emerge in near future. In addition, antenatal MRI also evaluates the maternal pelvis and provides vital information about fetal-pelvic disproportion.

By virtue of recent advances in MR technology and the need to practice evidence-based medicine, antenatal MRI is now rapidly moving from the realms of select academic medical centers into community practice in India. The article provides a brief update on antenatal MRI in routine clinical practice.