A round lesion with peripheral signal lower than that of CSF is located
posterior to the L4-5 disk space on sagittal T2 images through the lumbar
spine. Note that the central portion of the lesion is high in signal.
Axial PD (3, 5) and T2 (4, 6) images through the lesion demonstrate its
extradural location adjacent to the facet joint. Note that the outer rim
of the lesion is of low signal intensity.
Key words: mri degenerative