Table 1.

MRI evaluation for disc degeneration, central stenosis, and facet joint degeneration.

Classification of disc degeneration
Grade	Signal intensity	Structure	Distinction of nucleus and anulus
I	Hyperintense, isointense to CSF	Homogeneous, bright white	Clear
II	Hyperintense, isointense to CSF	Inhomogeneous with or without horizontal bands	Clear
III	Intermediate	Inhomogenous, gray	Unclear
IV	Intermediate to hypointense	Inhomogenous, gray to black	Lost
V	Hypointense	Inhomogenous, black	Lost
Classification of central canal stenosis
Grade	Definition
0	No lumbar stenosis without obliteration of anterior CSF space
1	Mild stenosis with separation of all cauda equina
2	Moderate stenosis with some cauda equine aggregated
3	Severe stenosis with none of the cauda equine separated
Classification of facet joint degeneration
Grade	Criteria
0	Normal facet joint space (2-4mm width)
1	Narrowing of the facet joint space (< 2mm) and/or small osteophyte and/or mild hypertrophy of the articular process
2	Narrowing of the facet joint space and/or moderate osteophyte and/or moderate hypertrophy of the articular process and/or mild subarticular bone erosions
3	Narrowing of the facet joint space and/or large osteophytes and/or severe hypertrophy of the articular process and/or severe subarticular bone erosions and/or subchondral cysts

CSF: cerebrospinal fluid.