Table 1.

Pfirrmann grading system of lumbar disc degeneration

Grade	Structure	Distinction of nucleus and annulus	Signal intensity	Disc height
I	Homogeneous, bright white	Clear	Hyperintense, isointense to CSF	Normal
II	Inhomogeneous with or without horizontal bands	Clear	Hyperintense, isointense to CSF	Normal
III	Inhomogeneous, gray	Unclear	Intermediate to CSF	Normal to slightly decreased
IV	Inhomogeneous, gray to black	Lost	Intermediate to hypointense to CSF	Normal to moderately decreased
V	Inhomogeneous black	Lost	Hypointense to CSF	Collapsed

CSF cerebrospinal fluid