To investigate the diagnostic value of ultrasound and MRI in fetal bronchopulmonary sequestration (BPS).

The 7 pregnant women with suspected fetal BPS were examined with a 1.5 T MR unit within 24 h after prenatal ultrasound in Hubei Maternal and Children's Hospital during July 2013 to February 2015. The imaging protocol included half-fourier acquisition single shot turbo SE (HASTE), true fast imaging with steady state precession (True FISP) in axial, frontal and sagittal planes relative to the fetal thorax. Prenatal MRI findings have been compared with postnatal enhanced computed tomography or biopsy.

The locations of BPS were in left side in 5 cases and in right side in 2 cases. One case was complicated with congenital cystic adenomatoid malformation (CCAM) of lung. Ultrasound showed the intrathoracic mass as a hyperechoic lesion and the feeding artery could be found by Doppler ultrasonography. T₂WI could reveal not only the hyperintense lesions with clear boundary, but also the hypointense feeding artery originating from systemic circulation. Compared with pathological examination or enhanced CT, both of the ultrasound and the MRI could locate the lesions; however 2 feeding arteries were misjudged.

Prenatal ultrasound is the first-choice diagnostic modality for BPS. MRI can demonstrate the location, morphology and the feeding arteries of the fetal BPS, and also estimate the volume of normal lungs, which could be an important supplement to prenatal ultrasound in prenatal diagnosis and prognostic prediction of BPS.