Purpose: To characterize the imaging features of bronchogenic cysts.
Materials and methods: The computed tomographic (CT) and/or magnetic resonance (MR) or ultrasonographic images in 68 histopathologically proved cases of bronchogenic cyst in 38 male and 30 female patients, aged newborn to 72 years (mean, 22 years), were retrospectively reviewed.
Results: There were 58 mediastinal and 10 extramediastinal cysts. At CT (n = 62), 60 cysts were sharply marginated with smooth (n = 35) or lobulated (n = 25) borders. Twenty-five cysts were of water attenuation, 25 were of soft-tissue attenuation, two were air filled, two had an air-fluid level, and two had dependent milk of calcium. On T1-weighted MR images (n = 23), 18 cysts were hyperintense and five were isointense to cerebrospinal fluid. On T2-weighted MR images (n = 18), 17 cysts were isointense or hyperintense to cerebrospinal fluid. Of the 25 soft-tissue-attenuation lesions at CT, 11 appeared cystic because of internal homogeneity, lack of internal enhancement, mural enhancement, and characteristic location. Fourteen appeared solid based on morphology and attenuation. MR imaging of nine of the latter showed marked hyperintensity on T2-weighted images.
Conclusion: CT of bronchogenic cysts typically shows sharply marginated mediastinal masses of soft-tissue or water attenuation. Most appear cystic. A minority appear solid and can be confused with other lesions; MR imaging can be useful for elucidating the cystic nature of these lesions.