Figure 2. Interspinous fluid with L4-5 one level stenosis on T2 sagittal magnetic resonance imaging (MRI) studies.
A: L5-S1 large interspinous hyperintense fluid (two solid white arrows) with no ligamentous enlargement. L4-5 minimal ligamentous enlargement posteriorly (dashed white arrow) with early canal stenosis. L4-5 intervertebral disc has early signs of T2 signal desiccation.
B: Narrowed and dessicated intervertebral disc at L4-5 with annular bulge (dashed black arrow) with minimal dorsal posterior spinal cyst (dashed white arrow) causing posterior central canal stenosis connected to interspinous fluid (solid white arrows).
C: Grade 1 spondylolisthesis at L4-5 (dashed black arrow), posterior fibrous ligamentum flavum hypertrophy (dashed white arrow) and fluid in interspinous space (solid white arrows).
D: Degenerated narrowed L4-5 intervertebral disc with annular bulge and grade 1 spondylolisthesis (superior dashed black arrow). Grade 2 spondylolisthesis at L5-S1 with marked endplate degeneration (inferior dashed black arrow). Posterior interspinous cyst (solid red arrow) with marked ligamentous hypertrophy and stenosis at L4-5 (two dashed white arrows). Marked edema and displacement of cauda equina roots.