The modified Pfirrmann classification is an adaptation of the original Pfirrmann classification for grading lumbar intervertebral disc degeneration into 8 different grades[^1].
Classification
Grade | Signal of the nucleus pulposus and the inner fibers of the annulus fibrosus | Demarcation between the inner and outer fibers of the annulus fibrosus in the dorsal portion of the intervertebral disc | Intervertebral disc height |
1 | Uniformly hyperintense, equivalent to Cerebrospinal fluid (CSF) | Clearly demarcated | Normal |
2 | Hyperintense (> presacral fat and < CSF) ± hypointense intranuclear cleft | Clearly demarcated | Normal |
3 | Hyperintense, but < presacral fat | Clearly demarcated | Normal |
4 | Slightly hyperintense (signal of the inner fibers > signal of the outer fibers of the annulus) | Poorly demarcated | Normal |
5 | Hypointense (= signal of the outer fibers of the annulus) | Poorly demarcated | Normal |
6 | Hypointense | Poorly demarcated | < 30 % reduction in intervertebral disc height |
7 | Hypointense | Poorly demarcated | 30-60 % reduction in intervertebral disc height |
8 | Hypointense | Poorly demarcated | > 60 % reduction in intervertebral disc height |
