Background Multidetector CT is currently the best imaging method for detecting tracheal diverticulum (TD). Compared with CT, MRI is radiation-free and has higher resolution. However, the MRI characteristics of this disease have not been previously reported. The present retrospective study compared the MR and CT imaging features of TD, aiming to examine the role of MRI in TD diagnosis and management. Methods Imaging data were collected in 26 TD patients divided into two groups, including the uninfected and infected groups. The MR and CT imaging features (size/wall/channel) of uninfected patients were compared. The performances of MRI and CT in diagnosing and monitoring therapeutic efficacy in infected TD patients were comparatively assessed. Results The uninfected group comprised 25 cases with 25 lesions confirmed by CT, including 23 lesions (92%) detected by MRI, with an average diameter of 8.5 mm (range from 3 to 15 mm). Meanwhile, the average diameter was 7.8 mm as measured by CT (range from 2.8 mm to 14.7 mm). The lesion diameters of the two cases not detected by MRI were 2.3 mm and 2 mm. MRI detected walls of all the 23 lesions (23/23), while CT detected no wall (0/23). CT showed channels in 18 lesions (18/23) versus3 for MRI (3/23). The infected case presented with a paratracheal abscess; MRI clearly showed a relationship between the abscess and the trachea, while CT could not show the lesion source. MRI also sensitively showed the whole process of lesion absorption. Conclusions MRI can be used as a supplementary method for TD diagnosis, providing information about the wall that cannot be obtained by CT. MRI is superior to CT in diagnosing infected TD cases presenting with a paratracheal abscess, and in monitoring therapeutic efficacy in these patients.