Fig. 2
From: Spectrum of MRI features of ganglion and synovial cysts
a, b. Lumbar facet synovial cyst in a 50-year-old man with a history of spinal surgery due to spondylolisthesis 20Â years earlier, presenting with low back pain. Axial (a) and sagittal (b) T2-weighted images show a mildly hyperintense extradural rounded lesion (dashed arrows) arising from the right L4/L5 facet joint, which presents marked degenerative changes and fluid (asterisk). Note the compression of the thecal sac, displaced posteriorly (arrow in b) and to the left side (arrow in a). Case courtesy of Dr. Carlos Casimiro. Neuroradiology Department, Centro Hospitalar de Lisboa Norte. Lisbon, Portugal