Computed tomography of mediastinal bronchogenic cysts.

The computed tomographic (CT) findings in seven cases of mediastinal bronchogenic cysts were reviewed. Two showed homogeneous high density masses with CT numbers of 97 and 89 Hounsfield units (HU). One had a CT number of 40 HU. Four cases had low density masses with CT numbers ranging from -3 to 20 HU; however, two of these four low density masses had either high density outer walls or deposits. All but one of the patients' chest radiographs revealed similar water density masses. Radiographic evidence of calcium deposits was previously considered rare, but its demonstration with CT appears to be common in mediastinal bronchogenic cysts.