Grade Structure

Distinction of the nucleus and annulus

Signal intensity

Height of the intervertebral disk

I: Homogeneous, bright white

Clear

Hyperintense, isointense to CSF

Normal

II: Heterogeneous with or without horizontal bands

Clear

Hyperintense, isointense to CSF

Normal

III: Heterogeneous, gray

Unclear

Intermediate

Normal to slightly decreased

IV: Heterogeneous, gray or black

Lost

Intermediate or hypointense

Normal to moderately decreased

V: Heterogeneous, black

Lost

Hypointense

Collapsed disk space