Fig. 7

Advantages of CT and MRI. (a) Supplementary CT and (b-f) MRI of the patient shown in Fig. 1. CT demonstrates erosion not only at the base of the dens, but also at the tip and at the atlanto-axial and atlanto-occipital joints, which are difficult to visualise by radiography. MRI, (b) sagittal STIR and (c) sagittal T1 of the entire cervical spine and post-contrast T1FS images of the atlanto-axial region, (d) sagittal, (e) coronal and (f) axial. Oedematous voluminous pannus surrounding the dens is seen on the STIR and T1 images (black arrows) in addition to C4/5 and C5/6 disc degeneration with posterior protrusion of the disc at C4/5. The post-contrast T1FS images confirm the presence of vascularised enhancing pannus around the dens (white arrows) and demonstrate improved anatomical delineation compared with the STIR image. There is no sign of spinal cord compression