Comparison of magnetic resonance imaging and ultrasonography in the prenatal diagnosis of congenital thoracic abnormalities.

OBJECTIVES

To evaluate prenatal MRI in the diagnosis of fetal thoracic abnormalities and to determine whether MRI provides useful information in addition to that of ultrasonography (US).

METHODS

Ultrafast MR scanning was performed in 7 pregnant women in whom US was suspicious of fetal congenital anomalies of the thorax [3 cases of congenital diaphragmatic hernia (CDH), 3 cases of chylothorax and 1 case of congenital cystic adenomatoid malformation (CCAM) type III]. The presence, position, size and characteristics of the congenital lesions were determined and compared with postnatal diagnoses.

RESULTS

The MRI diagnoses were 3 cases of CDH, 2 of chylothorax and one each of esophageal atresia and CCAM type III. The results of MRI were in agreement with those of US in 6 cases and in disagreement in 1 case of esophageal atresia. Final diagnoses were confirmed at surgery or autopsy in all fetuses. Combined use of MR and US imaging enabled a correct diagnosis in 5 cases and led to an error in the diagnosis of 1 fetus with bronchial stenosis, which had been diagnosed as CCAM type III by US and MRI. MRI led to a correct diagnosis in 1 fetus with esophageal atresia, in whom US had been equivocal in the prenatal diagnosis.

CONCLUSION

MRI helped further characterize the fetal thoracic lesions and confirmed or changed the prenatal diagnosis based on US. MRI seems to be powerful in the prenatal diagnosis of thoracic lesions that are atypical or complicated by multiple abnormalities.