Imaging features of primary mediastinal cysts with clinical and histopathologic correlation / 中华放射学杂志

ABSTRACT

Objective To characterize the imaging features of mediastinal cysts and gain a better understanding of atypical manifestations of various mediastinal cysts and improve the level of diagnosis. Methods The CT and/or MR images(CT n=28, MRI n=26, CT and MRI n=10), surgical information, and pathologic material in 44 histopathologically proved cases of mediastinal cyst were retrospectively reviewed. Results The mediastinal cysts were located in the anterior mediastinum(n=13), middle mediastinum(n=18), anterior-middle mediastinum (n=2) and posterior mediastinum(n=11). Bronchogenic cysts and pericardial cysts were atypically located in 7/20(35%)and 5/6 respectively. The density of 42.9% cysts on CT was close to that of water. Each of the cysts had a high signal intensity that was equal to or greater than cerebrospinal fluid on T_2-weighted MR images. One cyst showed marked loss of signal on MR hydrography. The signal intensities of the cysts were variable on T_1-weighted images. The signal intensity of MRI was not homogeneous in 5 and the reasons were different. Fourteen cases were misdiagnosed. Conclusion 1.The cysts with soft-tissue attenuation on CT in the anterior and posterior mediastinum may be easily misdiagnosed as neoplasm. Pericardial cysts located in the paratrachea may be easily misdiagnosed as bronchogenic cysts .2. MRI can be used to diagnose the cysts with high density on CT.3. Heterogeneous signal on MRI and loss of signal on MR hydrography might be the reasons for misdiagnosis.