Table 2.

The grading system for degenerative disc disease (modified from²¹)

Grade for study	Grade from paper	Signal from nucleus and inner fibres of anulus	Distinction between inner and outer fibres of anulus at posterior aspect of disc	Height of disc
1	1	Uniformly hyperintense (=CSF)	Distinct	Normal
1	2	Hyperintense (>presacral fat;<CSF) ± hypointense intranuclear cleft	Distinct	Normal
1	3	Hyperintense (<presacral fat)	Distinct	Normal
2	4	Mildly hyperintense (slightly >outer fibres of anulus)	Indistinct	Normal
2	5	Hypointense (=outer fibres of anulus)	Indistinct	Normal
3	6	Hypointense	Indistinct	<30% reduction disc height
4	7	Hypointense	Indistinct	30–60% reduction disc height
4	8	Hypointense	Indistinct	>60% reduction disc height

CSF, cerebrospinal fluid.