The contribution of fetal MR imaging to the assessment of oesophageal atresia.

OBJECTIVE: Present challenges are to improve the diagnosis rate of oesophageal atresia (OA) and evaluate as completely as possible a fetus affected by OA, specifically the type of OA and the length of the gap. Our aim was to evaluate the accuracy of fetal MR imaging (fMRI) for diagnosis of OA.

METHODS: We reviewed fMRI performed because of sonographic suspicion of an OA. The signs reviewed included stomach size, "pouch sign", bowing of the trachea and visualization of the lower oesophageal lumen. The fetuses were assigned by consensus as having or not having EA, as well as having a tracheaoesophageal fistula (TOF). All findings were correlated with postnatal data. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated.

RESULTS: Se, Sp, PPV and NPV of the technique were respectively 91%, 100%, 100% and 88%. The presence of the pouch sign yielded corresponding values of 82%, 100%, 100% and 78%. Mid-tracheal bowing was correlated positively with EA. The type of atresia was correctly evaluated in 90% of patients.

CONCLUSION: fMRI is useful for the diagnosis of EA through the visualization of the oesophageal pouch or through associated signs such as tracheal bowing. Visualization of the lower oesophageal lumen seems to be a good sign of TEF.

KEY POINTS: • Challenges are to improve the prenatal diagnosis of EA and associated malformations. • fMRI is able to diagnose EA through demonstration of the pouch sign. • Tracheal bowing is a promising indirect sign of EA. • Tracheoesophageal fistula can also be suspected thanks to fMRI. • Obstetrical US, fMRI and fetal CT are complementary for assessing associated malformations.