Space Occupying Lesions in the Fetal Chest Evaluated by MRI

BACKGROUND: The most common space occupying lesions of the fetal thorax are congenital diaphragmatic hernia (CDH), congenital cystic adenomatoid malformation (CCAM), and bronchopulmonary sequestration (BPS). Although applications of prenatal MRI have been vastly improved in the recent years, its use in the assessment of space occupying lesions of the fetal chest differs among centers. OBJECTIVES: To evaluate MRI findings in the diagnosis and follow-up of space-occupying lesions in the fetal chest with the review of relevant literature. PATIENTS AND METHODS: The fetuses with space-occupying lesions of the chest were retrieved from our 1.5T fetal MRI database of 347 patients. MRI features including the shape, signal characteristics, feeding artery, margin, mass effect, affected organ parts and anatomic location were reviewed. The results were correlated with the pathology results, follow-up and surgical findings. RESULTS: Nineteen MR images of 17 fetuses (mean gestational age, 23.8 weeks) with spaceoccupying lesions (5 CCAMs including one involuted case), 2 BPSs, 2 hybrid lesions, 8 CDH) were evaluated. One case of CCAM completely involuted in utero, four newborns were operated, and the resulting 12 fetuses were terminated. The surgical and pathological findings were in accordance with MRI findings. CONCLUSION: MRI can reliably differentiate CDH from CCAM and BPS in utero. Follow-up is of utmost importance as lesions may involute or progress in utero. Prenatal MRI findings help postnatal decision-making, surgical planning and parental counseling.